Benzene: Toxic, volatile, flammable liquid hydrocarbon byproduct of coal distillation. It is used as an industrial solvent in paints, varnishes, lacquer thinners, gasoline, etc. Benzene causes central nervous system damage acutely and bone marrow damage chronically and is carcinogenic. It was formerly used as parasiticide.Benzene DerivativesSorbic Acid: Mold and yeast inhibitor. Used as a fungistatic agent for foods, especially cheeses.Toluene: A widely used industrial solvent.HydroquinonesXylenes: A family of isomeric, colorless aromatic hydrocarbon liquids, that contain the general formula C6H4(CH3)2. They are produced by the destructive distillation of coal or by the catalytic reforming of petroleum naphthenic fractions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Phenol: An antiseptic and disinfectant aromatic alcohol.Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Petroleum: Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.Catechols: A group of 1,2-benzenediols that contain the general formula R-C6H5O2.Air Pollutants, Occupational: Air pollutants found in the work area. They are usually produced by the specific nature of the occupation.Maximum Allowable Concentration: The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (From Lewis Dictionary of Toxicology, 1st ed)Hydrocarbons, Aromatic: Organic compounds containing carbon and hydrogen in the form of an unsaturated, usually hexagonal ring structure. The compounds can be single ring, or double, triple, or multiple fused rings.Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.HydrocarbonsChemical Industry: The aggregate enterprise of manufacturing and technically producing chemicals. (From Random House Unabridged Dictionary, 2d ed)Cyclohexanes: Six-carbon alicyclic hydrocarbons.ChlorobenzenesPhenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Black Widow Spider: A venomous New World spider with an hourglass-shaped red mark on the abdomen.Liability, Legal: Accountability and responsibility to another, enforceable by civil or criminal sanctions.Malpractice: Failure of a professional person, a physician or lawyer, to render proper services through reprehensible ignorance or negligence or through criminal intent, especially when injury or loss follows. (Random House Unabridged Dictionary, 2d ed)Judicial Role: The kind of action or activity proper to the judiciary, particularly its responsibility for decision making.CaliforniaLawyers: Persons whose profession is to give legal advice and assistance to clients and represent them in legal matters. (American Heritage Dictionary, 3d ed)Hexachlorobenzene: An agricultural fungicide and seed treatment agent.Ustilaginales: An order of basidiomycetous fungi; some species are parasitic on grasses (POACEAE) and maize.Hydrocarbons, Chlorinated: Hydrocarbon compounds with one or more of the hydrogens replaced by CHLORINE.Fungicides, Industrial: Chemicals that kill or inhibit the growth of fungi in agricultural applications, on wood, plastics, or other materials, in swimming pools, etc.Triticum: A plant genus of the family POACEAE that is the source of EDIBLE GRAIN. A hybrid with rye (SECALE CEREALE) is called TRITICALE. The seed is ground into FLOUR and used to make BREAD, and is the source of WHEAT GERM AGGLUTININS.Skiing: A snow sport which uses skis to glide over the snow. It does not include water-skiing.United States Occupational Safety and Health Administration: An office in the Department of Labor responsible for developing and establishing occupational safety and health standards.National Institute for Occupational Safety and Health (U.S.): An institute of the CENTERS FOR DISEASE CONTROL AND PREVENTION which is responsible for assuring safe and healthful working conditions and for developing standards of safety and health. Research activities are carried out pertinent to these goals.United States Department of Veterans Affairs: A cabinet department in the Executive Branch of the United States Government concerned with overall planning, promoting, and administering programs pertaining to VETERANS. It was established March 15, 1989 as a Cabinet-level position.Visual Prosthesis: Artificial device such as an externally-worn camera attached to a stimulator on the RETINA, OPTIC NERVE, or VISUAL CORTEX, intended to restore or amplify vision.tert-Butyl AlcoholUnited States Government Agencies: Agencies of the FEDERAL GOVERNMENT of the United States.Nisin: A 34-amino acid polypeptide antibiotic produced by Streptococcus lactis. It has been used as a food preservative in canned fruits and vegetables, and cheese.Judgment: The process of discovering or asserting an objective or intrinsic relation between two objects or concepts; a faculty or power that enables a person to make judgments; the process of bringing to light and asserting the implicit meaning of a concept; a critical evaluation of a person or situation.Reference Standards: A basis of value established for the measure of quantity, weight, extent or quality, e.g. weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy.National Institutes of Health (U.S.): An operating division of the US Department of Health and Human Services. It is concerned with the overall planning, promoting, and administering of programs pertaining to health and medical research. Until 1995, it was an agency of the United States PUBLIC HEALTH SERVICE.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Cycloaddition Reaction: Synthetic organic reactions that use reactions between unsaturated molecules to form cyclical products.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Cyclohexenes: Six-carbon alicyclic hydrocarbons which contain one or more double bonds in the ring. The cyclohexadienes are not aromatic, in contrast to BENZOQUINONES which are sometimes called 2,5-cyclohexadiene-1,4-diones.Alkenes: Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)Acetylene

Methodological issues in biomonitoring of low level exposure to benzene. (1/773)

Data from a pilot study on unmetabolized benzene and trans,trans muconic acid (t,t-MA) excretion in filling station attendants and unexposed controls were used to afford methodological issues in the biomonitoring of low benzene exposures (around 0.1 ppm). Urinary concentrations of benzene and t,t-MA were measured by dynamic head-space capillary GC/FID and HPLC, respectively. The accuracy of the HPLC determination of t,t-MA was assessed in terms of inter- and intra-method reliability. The adequacy of urinary t,t-MA and benzene as biological markers of low benzene exposure was evaluated by analysing the relationship between personal exposure to benzene and biomarker excretion. Filling station attendants excreted significantly higher amounts of benzene, but not of t,t-MA, than controls. Adjusting for occupational benzene exposure, smokers excreted significantly higher amounts of t,t-MA, but not of unmetabolized benzene, than nonsmokers. A comparative analysis of the present and previously published biomonitoring surveys showed a good inter-study agreement regarding the amount of t,t-MA and unmetabolized benzene excreted (about 0.1-0.2 mg/l and 1-2 micrograms/l, respectively) per unit of exposure (0.1 ppm). For each biomarker, based on the distribution of parameters observed in the pilot study, we calculated the minimum sample size required to estimate the population mean with given confidence and precision.  (+info)

The alkene monooxygenase from Xanthobacter strain Py2 is closely related to aromatic monooxygenases and catalyzes aromatic monohydroxylation of benzene, toluene, and phenol. (2/773)

The genes encoding the six polypeptide components of the alkene monooxygenase from Xanthobacter strain Py2 (Xamo) have been located on a 4.9-kb fragment of chromosomal DNA previously cloned in cosmid pNY2. Sequencing and analysis of the predicted amino acid sequences indicate that the components of Xamo are homologous to those of the aromatic monooxygenases, toluene 2-, 3-, and 4-monooxygenase and benzene monooxygenase, and that the gene order is identical. The genes and predicted polypeptides are aamA, encoding the 497-residue oxygenase alpha-subunit (XamoA); aamB, encoding the 88-residue oxygenase gamma-subunit (XamoB); aamC, encoding the 122-residue ferredoxin (XamoC); aamD, encoding the 101-residue coupling or effector protein (XamoD); aamE, encoding the 341-residue oxygenase beta-subunit (XamoE); and aamF, encoding the 327-residue reductase (XamoF). A sequence with >60% concurrence with the consensus sequence of sigma54 (RpoN)-dependent promoters was identified upstream of the aamA gene. Detailed comparison of XamoA with the oxygenase alpha-subunits from aromatic monooxygenases, phenol hydroxylases, methane monooxygenase, and the alkene monooxygenase from Rhodococcus rhodochrous B276 showed that, despite the overall similarity to the aromatic monooxygenases, XamoA has some distinctive characteristics of the oxygenases which oxidize aliphatic, and particularly alkene, substrates. On the basis of the similarity between Xamo and the aromatic monooxygenases, Xanthobacter strain Py2 was tested and shown to oxidize benzene, toluene, and phenol, while the alkene monooxygenase-negative mutants NZ1 and NZ2 did not. Benzene was oxidized to phenol, which accumulated transiently before being further oxidized. Toluene was oxidized to a mixture of o-, m-, and p-cresols (39.8, 18, and 41.7%, respectively) and a small amount (0.5%) of benzyl alcohol, none of which were further oxidized. In growth studies Xanthobacter strain Py2 was found to grow on phenol and catechol but not on benzene or toluene; growth on phenol required a functional alkene monooxygenase. However, there is no evidence of genes encoding steps in the metabolism of catechol in the vicinity of the aam gene cluster. This suggests that the inducer specificity of the alkene monooxygenase may have evolved to benefit from the naturally broad substrate specificity of this class of monooxygenase and the ability of the host strain to grow on catechol.  (+info)

Benzene-induced uncoupling of naphthalene dioxygenase activity and enzyme inactivation by production of hydrogen peroxide. (3/773)

Naphthalene dioxygenase (NDO) is a multicomponent enzyme system that oxidizes naphthalene to (+)-cis-(1R,2S)-1,2-dihydroxy-1, 2-dihydronaphthalene with consumption of O2 and two electrons from NAD(P)H. In the presence of benzene, NADH oxidation and O2 utilization were partially uncoupled from substrate oxidation. Approximately 40 to 50% of the consumed O2 was detected as hydrogen peroxide. The rate of benzene-dependent O2 consumption decreased with time, but it was partially increased by the addition of catalase in the course of the O2 consumption by NDO. Detailed experiments showed that the total amount of O2 consumed and the rate of benzene-induced O2 consumption increased in the presence of hydrogen peroxide-scavenging agents, and further addition of the terminal oxygenase component (ISPNAP) of NDO. Kinetic studies showed that ISPNAP was irreversibly inactivated in the reaction that contained benzene, but the inactivation was relieved to a high degree in the presence of catalase and partially relieved in the presence of 0.1 mM ferrous ion. Benzene- and naphthalene-reacted ISPNAP gave almost identical visible absorption spectra. In addition, hydrogen peroxide added at a range of 0.1 to 0.6 mM to the reaction mixtures inactivated the reduced ISPNAP containing mononuclear iron. These results show that hydrogen peroxide released during the uncoupling reaction acts both as an inhibitor of benzene-dependent O2 consumption and as an inactivator of ISPNAP. It is proposed that the irreversible inactivation of ISPNAP occurs by a Fenton-type reaction which forms a strong oxidizing agent, hydroxyl radicals (. OH), from the reaction of hydrogen peroxide with ferrous mononuclear iron at the active site. Furthermore, when [14C]benzene was used as the substrate, cis-benzene 1,2-dihydrodiol formed by NDO was detected. This result shows that NDO also couples a trace amount of benzene to both O2 consumption and NADH oxidation.  (+info)

Adenosylcobalamin-mediated methyl transfer by toluate cis-dihydrodiol dehydrogenase of the TOL plasmid pWW0. (4/773)

We identified and characterized a methyl transfer activity of the toluate cis-dihydrodiol (4-methyl-3,5-cyclohexadiene-cis-1, 2-diol-1-carboxylic acid) dehydrogenase of the TOL plasmid pWW0 towards toluene cis-dihydrodiol (3-methyl-4,5-cyclohexadiene-cis-1, 2-diol). When the purified enzyme from the recombinant Escherichia coli containing the xylL gene was incubated with toluene cis-dihydrodiol in the presence of NAD+, the end products differed depending on the presence of adenosylcobalamin (coenzyme B12). The enzyme yielded catechol in the presence of adenosylcobalamin, while it gave 3-methylcatechol in the absence of the cofactor. Adenosylcobalamin was transformed to methylcobalamin as a result of the enzyme reaction, which indicates that the methyl group of the substrate was transferred to adenosylcobalamin. Other derivatives of the cobalamin such as aquo (hydroxy)- and cyanocobalamin did not mediate the methyl transfer reaction. The dehydrogenation and methyl transfer reactions were assumed to occur concomitantly, and the methyl transfer reaction seemed to depend on the dehydrogenation. To our knowledge, the enzyme is the first dehydrogenase that shows a methyl transfer activity as well.  (+info)

Determination of the urinary benzene metabolites S-phenylmercapturic acid and trans,trans-muconic acid by liquid chromatography-tandem mass spectrometry. (5/773)

To investigate how various levels of exposure affect the metabolic activation pathways of benzene in humans and to examine the relationship between urinary metabolites and other biological markers, we have developed a sensitive and specific liquid chromatographic-tandem mass spectrometric assay for simultaneous quantitation of urinary S-phenylmercapturic acid (S-PMA) and trans,trans-muconic acid (t,t-MA). The assay involves spiking urine samples with [13C6]S-PMA and [13C6]t,t-MA as internal standards and clean up of samples by solid-phase extraction with subsequent analysis by liquid chromatography coupled with electrospray-tandem mass spectrometry-selected reaction monitoring (LC-ES-MS/MS-SRM) in the negative ionization mode. The efficacy of this assay was evaluated in human urine specimens from smokers and non-smokers as the benzene-exposed and non-exposed groups. The coefficient of variation of runs on different days (n = 8) for S-PMA was 7% for the sample containing 9.4 microg S-PMA/l urine, that for t,t-MA was 10% for samples containing 0.07 mg t,t-MA/l urine. The mean levels of urinary S-PMA and t,t-MA in smokers were 1.9-fold (P = 0.02) and 2.1-fold (P = 0.03) higher than those in non-smokers. The mean urinary concentration (+/-SE) was 9.1 +/- 1.7 microg S-PMA/g creatinine [median 5.8 microg/g, ranging from not detectable (1 out of 28) to 33.4 microg/g] among smokers. In non-smokers' urine the mean concentration was 4.8 +/- 1.1 microg S-PMA/g creatinine (median 3.6 microg/g, ranging from 1.0 to 19.6 microg/g). For t,t-MA in smokers' urine the mean (+/-SE) was 0.15 +/- 0.03 mg/g creatinine (median 0.11 mg/ g, ranging from 0.005 to 0.34 mg/g); the corresponding mean value for t,t-MA concentration in non-smokers' urine was 0.07 +/- 0.02 mg/g creatinine [median 0.03 mg/g, ranging from undetectable (1 out of 18) to 0.48 mg/g]. There was a correlation between S-PMA and t,t-MA after logarithmic transformation (r = 0.41, P = 0.005, n = 46).  (+info)

Metabolism of [14C]phenol in the isolated perfused mouse liver. (6/773)

A previous report from this laboratory focused on the metabolism of [14C]benzene (BZ) in the isolated, perfused, mouse liver (C. C. Hedli, et al., 1997, Toxicol. Appl. Pharmacol. 146, 60-68). Whereas administration of BZ to mice results in bone marrow depression (R. Snyder et al., 1993, Res. Commun. Chem. Pathol. Pharmacol. 20, 191-194), administration of phenol (P), the major metabolite of BZ, does not. It was, therefore, of interest to determine whether the metabolic fate of P produced during BZ metabolism differed from that of P metabolized in the absence of BZ. Mouse livers were perfused with a solution of [14C]P in both the orthograde (portal vein to central vein) and retrograde (central vein to portal vein) direction to investigate the metabolic zonation of enzymes involved in P hydroxylation and conjugation. Perfusate samples were collected, separated by HPLC, and tested for radioactivity. Unconjugated metabolites were identified by comparing their retention times with nonradiolabeled standards, which were detected by UV absorption. Conjugated metabolites were identified and collected on the basis of radiochromatogram results, hydrolyzed enzymatically, and identified by co-chromatography with unlabeled BZ metabolites. The objective was to compare and quantify the metabolites formed during the perfusion of P in the orthograde and retrograde directions and to compare the orthograde P-perfusion results with the orthograde BZ results reported previously. Regardless of the direction of P perfusion, the major compounds released from the liver were P. phenylgucuronide, phenylsulfate, hydroquinone (HQ), and HQ glucuronide. A comparison of the results of perfusing P in the orthograde versus the retrograde direction showed that more P was recovered unchanged and more HQ was formed during retrograde perfusion. The results suggest that enzymes involved in P hydroxylation are generally closer to the central vein than those involved in conjugation, and that during retrograde perfusion, P metabolism may be limited by the sub-optimal conditions of perfusion. Comparison of the orthograde perfusion studies of P and BZ revealed that a larger percentage of the radioactivity released from the liver was identified as unconjugated HQ after BZ perfusion than after P perfusion. In addition, the amount of radioactivity covalently bound to liver macromolecules was measured after each perfusion and determined to be proportional to the amount of HQ and HQG detected in the perfusate samples.  (+info)

Environmental exposure to volatile organic compounds among workers in Mexico City as assessed by personal monitors and blood concentrations. (7/773)

Benzene, an important component in gasoline, is a widely distributed environmental contaminant that has been linked to known health effects in animals and humans, including leukemia. In Mexico City, environmental benzene levels, which may be elevated because of the heavy traffic and the poor emission control devices of older vehicles, may pose a health risk to the population. To assess the potential risk, portable passive monitors and blood concentrations were used to survey three different occupational groups in Mexico City. Passive monitors measured the personal exposure of 45 workers to benzene, ethylbenzene, toluene, o-xylene and m-/p-xylene during a work shift. Blood concentrations of the above volatile organic compounds (VOCs), methyl tert-butyl ether, and styrene were measured at the beginning and the end of a work shift. Passive monitors showed significantly higher (p > 0.0001) benzene exposure levels among service station attendants (median = 330 microg/m3; range 130-770) as compared to street vendors (median = 62 microg/m3; range 49-180) and office workers (median = 44 microg/m3, range 32-67). Baseline blood benzene levels (BBLs) for these groups were higher than those reported for similar populations from Western countries (median = 0.63 microg/L, n = 24 for service station attendants; median = 0.30 microg/L, n = 6 for street vendors; and median = 0.17 microgr;g/L, n = 7 for office workers). Nonsmoking office workers who were nonoccupationally exposed to VOCs had BBLs that were more than five times higher than those observed in a nonsmoking U.S. population. BBLs of participants did not increase during the work shift, suggesting that because the participants were chronically exposed to benzene, complex pharmacokinetic mechanisms were involved. Our results highlight the need for more complete studies to assess the potential benefits of setting environmental standards for benzene and other VOCs in Mexico.  (+info)

Microbial communities associated with anaerobic benzene degradation in a petroleum-contaminated aquifer. (8/773)

Microbial community composition associated with benzene oxidation under in situ Fe(III)-reducing conditions in a petroleum-contaminated aquifer located in Bemidji, Minn., was investigated. Community structure associated with benzene degradation was compared to sediment communities that did not anaerobically oxidize benzene which were obtained from two adjacent Fe(III)-reducing sites and from methanogenic and uncontaminated zones. Denaturing gradient gel electrophoresis of 16S rDNA sequences amplified with bacterial or Geobacteraceae-specific primers indicated significant differences in the composition of the microbial communities at the different sites. Most notable was a selective enrichment of microorganisms in the Geobacter cluster seen in the benzene-degrading sediments. This finding was in accordance with phospholipid fatty acid analysis and most-probable-number-PCR enumeration, which indicated that members of the family Geobacteraceae were more numerous in these sediments. A benzene-oxidizing Fe(III)-reducing enrichment culture was established from benzene-degrading sediments and contained an organism closely related to the uncultivated Geobacter spp. This genus contains the only known organisms that can oxidize aromatic compounds with the reduction of Fe(III). Sequences closely related to the Fe(III) reducer Geothrix fermentans and the aerobe Variovorax paradoxus were also amplified from the benzene-degrading enrichment and were present in the benzene-degrading sediments. However, neither G. fermentans nor V. paradoxus is known to oxidize aromatic compounds with the reduction of Fe(III), and there was no apparent enrichment of these organisms in the benzene-degrading sediments. These results suggest that Geobacter spp. play an important role in the anaerobic oxidation of benzene in the Bemidji aquifer and that molecular community analysis may be a powerful tool for predicting a site's capacity for anaerobic benzene degradation.  (+info)

An extremely well-conducted meta-analysis by researchers from the Netherlands has clearly shown that occupational benzene exposure is associated with lymphoid cancers.. The researchers performed meta-analyses of occupational cohort studies for five different lymphoma categories: Hodgkin lymphoma (HL), non-Hodgkin lymphoma (NHL), multiple myeloma (MM), acute lymphocytic leukemia (ALL), and chronic lymphocytic leukemia (CLL). They assessed three study quality dimensions to evaluate the impact of study quality variations on meta-relative risks (mRR): year-of-start of follow-up, strength of the reported AML association, and quality of benzene exposure assessment. Data synthesis mRRs for MM, ALL, and CLL increased with increasing study quality, regardless of the study quality dimension. mRRs for NHL also increased with increasing study quality, although less pronounced. The investigators concluded that their meta-analysis provides support for an association between occupational benzene exposure and ...
The research is to evaluate benzene metabolism after exposure at levels that can be found in the environment, such as the higher end concentrations in the air inside cars and buses while being driven in heavy traffic and inside private and public parking garages. To do so breath, urine, and blood samples prior to, during and after being exposed to benzene as well as benzene levels and benzene metabolites present are measured. The exposures take place in the Controlled Environmental Facility operated by the Environmental and Occupational Health Sciences Institute (EOHSI). This allows us to control the exact benzene air level and to use benzene containing 13C, a stable (non-radioactive) form of carbon, one of the atoms that make up benzene. Isotopes are different forms of the same atom. Using 13C will allow us to tell the difference between the benzene and the compounds it changes to in the body that come from our experiment compared to what is present in your body from other sources. In addition ...
Evaluation of benzene-induced hematotoxicity following exposure to low concentration is important for understanding mechanisms of toxicity and determining the dose response at benzene levels close to the current occupational exposure limit (1 ppm). Male B6C3F1 mice were exposed to 0, 1, 10, 100, or 200 ppm benzene by inhalation for 6 hr/day, 5 days/week, for 1, 2, 4, or 8 weeks. At each sampling time, we evaluated primitive and committed progenitor cells, differentiating and maturing lineage-specific cells, and stromal cells in the bone marrow; T and B lymphocytes of the spleen and thymus; micronucleated reticulocytes and erythrocytes; and standard blood parameters. At 100 and 200 ppm benzene, there were rapid and significant reductions in number of reticulocytes in the blood, B lymphocytes in the bone marrow and spleen, and an increased frequency of micronucleated reticulocytes in the bone marrow. At 10 ppm, the only parameter affected was a transient reduction in the number of splenic B ...
Meta-analysis on benzene exposure and non Hodgkin lymphoma June 30 2009 Gerard M H Swaen1 Shan P. Tsai2 Carol Burns1 1 Department of Epidemiology, The Dow Chemical Company, Midland, Michigan USA. 2 Shell Health, Shell Oil Company, Houston Texas, USA. Corresponding Author: Gerard M H Swaen, The Dow Chemical Company, P.O. Box 444, 4530 AK Terneuzen, The Netherlands 31-(0)43-3626042. E- mail: [email protected] Key words: benzene, non Hodgkin lymphoma, epidemiology, meta- analysis, occupation, risk Sir, A recent meta-analysis on benzene exposure and non Hodgkin lymphoma (NHL) concluded that the reviewed epidemiological studies provide "new evidence that benzene causes NHL." 1 The meta-analysis conducted by Steinmaus et al differed from the others in several aspects. Firstly, it selected subgroups with the highest putative exposure to avoid dilution. Secondly, cohort studies were adjusted for the Healthy Worker Effect (HWE) by considering the NHL deaths as cases and all other deaths as controls. A HWE ...
TY - JOUR. T1 - Pressure-induced oligomerization of benzene at room temperature as a precursory reaction of amorphization. AU - Shinozaki, Ayako. AU - Mimura, Koichi. AU - Kagi, Hiroyuki. AU - Komatu, Kazuki. AU - Noguchi, Naoki. AU - Gotou, Hirotada. PY - 2014. Y1 - 2014. N2 - Oligomerization of benzene at high pressures up to 16 GPa was investigated at room temperature using an opposed-anvil type pressure apparatus. The recovered samples were analyzed using GC-MS to identify and quantify the products after the high-pressure experiments. Some structural isomers of benzene dimer as well as biphenyl, naphthalene, and terphenyl isomers were detected at pressures higher than 13 GPa. The molar yield of the polycyclic aromatic hydrocarbons increased concomitantly with increasing pressure, although benzene still remained. The oligomerization is likely to occur when the neighbor distance of the benzene molecules exceeds the threshold of the reaction distance. The oligomerization is regarded as a ...
Benzene is a known leukemogen and may cause lymphoma as well, but its ability to , cause these conditions below 10 parts per million (ppm) in air are unclear. It is currently regulated in the United States at 1 ppm as an 8-hour time-weighted average and at a 5 ppm short-term exposure level for 15 minutes. There is a critical need to assess risks related to benzene exposure under 10 ppm because it is widely used industrially and a ubiquitous contaminant in the environment.. The National Cancer Institute (NCI) and the Chinese Academy of Preventive Medicine (CAPM), whose name was recently changed to the China Center for Disease Control (CDC) previously established a cohort of 75,000 workers exposed to benzene in 12 cities in China and 35,000 unexposed comparison workers, to investigate the relationship between benzene exposure and cancer risk, from 1972 to 1987. We followed up each worker using factory records and reported results suggesting that benzene exposure under 10 ppm may be associated with ...
Gas phase photocatalysis is an effective way for decomposing toxic organics, but the studies on benzene decomposition are relatively little. Our objective was to assess the capability of TiO 2 to decompose benzene and establish reaction mechanism for the photocatalytic oxidation of benzene. The photocatalytic oxidation of benzene in gas phase was performed in a recirculation photoreactor including a UV lamp emitting around 254 nm and TiO 2 coated glass plate. When the initial mass concentration of benzene was 50 mg/m 3, it was almost decomposed completely after 460 min on 0 1 g of TiO 2 and 0 013 m 2 area of catalyst layer activated by ultraviolet. The reaction time was reduced from 460 to 240 min when the irradiated area was 0 026 m 2. At ambient temperature, the adsorption of benzene on TiO 2 surface was not obvious, but the intermediate reaction product had very good adsorptivity, occupied the active sites and deactivated the catalyst. The IR results showed that the intermediate product
The Benzene attorneys at Nadrich & Cohen LLP have long been committed to defending individuals and the families of individuals who have suffered or died as a result of benzene exposure. Benzene is a highly dangerous chemical which has been known for decades to contain carcinogens, and millions of people every year come into contact with dangerous levels of benzene. Mary Johnson was one such victim, who tragically died after excessive benzene exposure.. Now we have reports that Johnsons children have brought a wrongful death suit against Total Petrochemicals & Refining USA, one of the worlds leading petrochemical companies. The suit alleges that Total Petrochemicals exposed Johnson to benzene, ultimately contributing to her untimely death.. The suit was filed on November 9, 2012, in Jefferson County District Court. The plaintiffs, James, Robert and Richard Johnson, seek justice for their mother, a former employee of Finas Port Arthur Refinery. It was there that she allegedly come into contact ...
Urine samples were collected from 64 men and 88 women in shoe factories and printing plants at the end of a seven hour day shift in the latter half of a week in spring. Urine samples were also taken from 43 men and 88 women in the same factories but who were not exposed to solvents. Exposure to benzene during the shift was monitored by passive dosimeters. Both phenol in urine and benzene in activated carbon were analysed with FID gas chromatographs. The urinary concentrations of phenol were linearly related to the time weighted average concentrations of benzene in the breathzone air; the variation was so small that those exposed to 10 ppm benzene could be separated from the non-exposed at least on a group basis when the phenol concentration was corrected either for creatinine concentration or for specific gravity. The urinary phenol concentrations corresponding to 10 ppm benzene were 47.5 mg/l (as observed), 57.9 mg/g creatinine, or 46.6 mg/l (specific gravity 1.016).. ...
Resonance in benzene - Resonance form of a compound is nothing but another way of representing Lewis dot structure of that compound. Benzene shows resonance as it has more than one way to place double bonds in the ring. Benzene shows 2 resonating structures. Resonance forms or resonating structures only differ in arrangement of electrons. So, resonance structure of benzene differs only in arrangement of electrons, number of carbon atoms and hydrogen atoms in benzene remain same. Double bonds present in benzene rotates in resonating structures of benzene and provide stability to benzene. Resonance structure shows possible structures of a compound. Resonance structures of benzene ring or benzene ring resonance structure - ...
Vacuum ultraviolet (VUV) lamps were used to enhance photocatalytic degradation of gaseous benzene. A series of transition metal modified TiO2 were developed to improve benzene removal efficiency and eliminate ozone byproduct. Among the prepared catalysts, Mn/TiO2 obtained the best catalytic activity toward benzene oxidation due to its superior capacity for ozone decomposition. The catalysts with better capacity for ozone decomposition have higher benzene removal efficiency. Photocatalytic oxidation efficiency of benzene under VUV irradiation reached 58%, which is over 20 times higher than that under 254nm UV irradiation. In addition, ozone can be completely eliminated by Mn/TiO2. Benzene degradation was greatly enhanced by ozone via catalytic ozonation. Water vapor played a dual role in benzene oxidation in the VUV-PCO process. Catalytic ozonation is mainly responsible for benzene abatement at low humidity while 185nm photooxidation is the dominant pathway at high humidity. © 2014 Elsevier B.V ...
Exposure to benzene, a known leukemogen and probable lymphomagen, has been demonstrated to result in oxidative stress, which has previously been associated with altered telomere length (TL). TL specifically has been associated with several health outcomes in epidemiologic studies, including cancer risk, and has been demonstrated to be altered following ... read more exposure to a variety of chemical agents. To evaluate the association between benzene exposure and TL, we measured TL by monochrome multiplex quantitative PCR in 43 workers exposed to high levels of benzene and 43 age and sex-matched unexposed workers in Shanghai, China. Benzene exposure levels were monitored using organic vapor passive dosimetry badges before phlebotomy. The median benzene exposure level in exposed workers was 31 ppm. The mean TL in controls, workers exposed to levels of benzene below the median (≤31 ppm), and above the median (,31 ppm) was 1.26±0.17, 1.25±0.16, and 1.37±0.23, respectively. Mean TL was ...
A pending lawsuit alleges that Texaco and Chevron are responsible for the death of a former employee who was exposed to dangerous levels of the chemical compound benzene while on the job. The dangerous, carcinogenic properties of benzene have been observed for nearly a century, and the California Benzene lawyers at Nadrich & Cohen have dedicated years to tirelessly defending the victims of benzene exposure. If you or someone you love has been affected by benzene, give us a call today at 1-800-722-0765.. The case involving Chevron and Texaco was filed by four plaintiffs: Keith Gebauer, Ronnie Gebauer, Lajunda Williams and Gaytha Guillot. The plaintiffs filed their suit on August 31, 2011, in Jefferson County District Court, claiming that their father-Fred Gebauer-died from lymphoma which he developed after a long career that involved working in close proximity to benzene and benzene-containing products.. The plaintiffs allege that the oil giants are legally responsible for their fathers death, ...
Author(s): Smith, Martyn T.; Yager, J; Steinmetz, K; Eastmond, D | Abstract: The metabolism of two of benzenes phenolic metabolites, phenol and hydroquinone, by peroxidase enzymes has been studied in detail. Studies employing horseradish peroxidase and human myeloperoxidase have shown that in the presence of hydrogen peroxide phenol is converted to 4,4-diphenoquinone and other covalent binding metabolites, whereas hydroquinone is converted solely to 1,4-benzoquinone. Surprisingly, phenol stimulates the latter conversion rather than inhibiting it, an effect that may play a role in the in vivo myelotoxicity of benzene. Indeed, repeated coadministration of phenol and hydroquinone to B6C3F1 mice results in a dramatic and significant decrease in bone marrow cellularity similar to that observed following benzene exposure. A mechanism of benzene-induced myelotoxicity is therefore proposed in which the accumulation and interaction of phenol and hydroquinone in the bone marrow and the peroxidase-dependent
Benzene is an organic chemical compoond wi the molecular formula C6H6. The benzene molecule is componed o sax caurbon atoms jynt in a ring wi ane hydrogen atom attached tae ilk. As it conteens anerly caurbon an hydrogen atoms, benzene is clessed as a hydrocaurbon. Benzene is a naitural constituent o crude ile an is ane o the elementar petrochemicals. Due tae the cyclic conteenous pi bond atween the caurbon atoms, benzene is clessed as an aromatic hydrocarbon, the seicont [n]-annulene ([6]-annulene). It is whiles abbreviatit PhH. Benzene is a colourless an heichly flammable liquid wi a sweet smell, an is responsible for the aroma aroond petrol stations. It is uised primarily as a precursor tae the manufacture o chemicals wi mair complex structur, uic as ethylbenzene an cumene, o that billions o kilogrammes are produced annually. As benzene haes a heich octane nummer, aromatic derivatives lik toluene an xylene teepically comprise up tae 25% o petrol. Benzene itsel haes been leemitit tae less than ...
Learn about industries that increase the risk of benzene exposure. Contact a lawyer at (866) 588-0600 to see if you have a benzene exposure lawsuit.
Benzene exposure has serious health effects. Breathing high levels of the substance can result in death, while low levels can cause drowsiness, dizziness, rapid heart rate, headaches, tremors, confusion, and unconsciousness. Eating or drinking foods containing high levels of benzene can cause vomiting, stomach irritation, dizziness, sleepiness, convulsions, rapid heart rate, and death.. The major effect of benzene from chronic (long-term) exposure is on the blood. Benzene damages the bone marrow and can cause a decrease in the production of red blood cells, leading to anemia. It can also cause excessive bleeding and may depress the immune system, increasing the chances of infection.. It has been reported that some women who breathed high levels of benzene for many months had irregular menstrual periods and a decrease in the size of their ovaries. It is not known whether benzene exposure affects the developing fetus in pregnant women or fertility in men.. Animal studies have shown low birth ...
Work operations where the only exposure to benzene is from liquid mixtures containing 0.5 percent or less of benzene by volume, or the vapors released from such liquids until September 12, 1988; work operations where the only exposure to benzene is from liquid mixtures containing 0.3 percent or less of benzene by volume or the vapors released from such liquids from September 12, 1988, to September 12, 1989; and work operations where the only exposure to benzene is from liquid mixtures containing 0.1 percent or less of benzene by volume or the vapors released from such liquids after September 12, 1989; except that tire building machine operators using solvents with more than 0.1 percent benzene are covered by paragraph (i) of this section ...
Segment 13, 14 and 15, Benzene and Its Derivatives deals channel, wholesalers, merchants, traders, Exploration Discoveries and End, appendix and data source.. Browse Full Global Benzene and Its Derivatives Market Report : www.intenseresearch.com/report/162993. Additionally, the global Benzene and Its Derivatives market is segmented on the basis of the region as well. It employs some practical tools to assess the expansion of the global Benzene and Its Derivatives market in the upcoming time. The global Benzene and Its Derivatives market report also offers a synopsis of the market on a global level that helps users in the decision-making processes, which in turn helps to boost their businesses. This synopsis incorporates the index growth as well as the competitive framework of the global Benzene and Its Derivatives market over the projected period.. The highlight of the global Benzene and Its Derivatives market research report is the in-depth market segmentation {Chlorobenzene, Toluene, ...
1-Methoxy-4-(2-propenyl)benzene, also known as methylchavicol or estragol, belongs to the class of organic compounds known as anisoles. These are organic compounds containing a methoxybenzene or a derivative thereof. 1-Methoxy-4-(2-propenyl)benzene is an extremely weak basic (essentially neutral) compound (based on its pKa). 1-Methoxy-4-(2-propenyl)benzene is a sweet, alcohol, and anise tasting compound. Outside of the human body, 1-Methoxy-4-(2-propenyl)benzene is found, on average, in the highest concentration within a few different foods, such as anises, fennels, and sweet basils and in a lower concentration in cumins, tarragons, and parsley. 1-Methoxy-4-(2-propenyl)benzene has also been detected, but not quantified in, several different foods, such as citrus, chinese cinnamons, caraway, fats and oils, and cloves. This could make 1-methoxy-4-(2-propenyl)benzene a potential biomarker for the consumption of these foods. 1-Methoxy-4-(2-propenyl)benzene, with regard to humans, has been linked to ...
Abstract : Benzene, toluene and p-xylene are derivatives of benzene, generally produced from crude petroleum and have numerous applications in industry. The aim of the present study was to evaluate the impact of biofield treatment on isotopic abundance of these benzene derivatives by gas chromatography-mass spectrometry (GC-MS). Benzene, toluene and p-xylene samples were divided into two parts: control and treatment. Control part was remained as untreated and treatment part was subjected to Mr. Trivedis biofield treatment. Control and treated samples were characterized using GC-MS. GC-MS data revealed that isotopic abundance ratio of 13C/12C or 2H/1H (PM+1/PM) of treated samples were significantly increased from un-substituted to substituted benzene rings (where, PM- primary molecule, PM+1- isotopic molecule either for 13C/12C and/or 2H/1H). The isotopic abundance ratio of 13C/12C or 2H/1H (PM+1/PM) in benzene was decreased significantly by 42.14% as compared to control. However, the isotopic ...
Manufacturing Science and Technology, AEMT2011: Synthesis, Properties and Application in Optical Memory of a Photochromic Diarylethene Based on Benzene Ring
Information about benzene and industries that use asphalt. Contact a lawyer for lawsuit info to see if you have a Benzene Exposure Lawsuit.
Benzene naturally occurs in crude oil and is used to make plastics, resins, synthetic fibers, dyes, detergents, additives and coatings, and pesticides. It is a widely used aromatic hydrocarbon which constitutes 1-2% of gasoline and other fuels. While benzene is a very useful hydrocarbon that offers diverse applications, it is also a known human carcinogen. Occupational Safety and Health Administration (OSHA) lists the PEL-TWA at 1 ppm, and the American Conference of Governmental Industrial Hygienists (ACGIH) have the TLV-TWA at 0.5 ppm. Industry requires a means to measure low concentrations of benzene (typically below 1 ppm) in the presence of various hydrocarbons, often 100 to 1000X the concentration of benzene.. Uniphos Envirotronic Inc., a recognized leader in colorimetric detection tubes, has developed a PID pre-filter tube for selective determination of benzene in air containing a mixture of volatile organic compounds (e.g. toluene, xylene, ethyl benzene, octane, etc.). The measuring range ...
Summary: Benzene is a colorless liquid with a sweet odor. It evaporates into the air very quickly and dissolves slightly in water. It is highly flammable and is formed from both natural processes and human activities.. Benzene is widely used in the United States; it ranks in the top 20 chemicals for production volume. Some industries use benzene to make other chemicals which are used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline, and cigarette smoke. ...
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Benzene law firm provides side effects of Benzene exposure information including, Acute Myelogenous Leukemia, Non-Hodgkins Lymphoma, and other leukemia and blood related diseases. Benzene exposure attorneys and lawyers at The Schmidt Firm, PLLC are handling Benzene lawsuits in all 50 states.
TY - JOUR. T1 - The effect of Ce ion substituted OMS-2 nanostructure in catalytic activity for benzene oxidation. AU - Hou, J.T.. AU - Li, Y.Z.. AU - Mao, M.Y.. AU - Zhao, X.J.. AU - Yue, Yuanzheng. PY - 2014. Y1 - 2014. U2 - 10.1039/c4nr04142a. DO - 10.1039/c4nr04142a. M3 - Journal article. VL - 6. SP - 15048. EP - 15058. JO - Nanoscale. JF - Nanoscale. SN - 2040-3364. IS - 24. ER - ...
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Benzene. Computer model of a molecule of benzene. Atoms are represented as spheres and are colour- coded: carbon (blue) and hydrogen (gold). Benzene is a highly flammable colourless liquid with a characteristic smell. It is obtained commercially from petroleum. Benzene is used as an additive in petrol, to manufacture other chemicals, and as a solvent for many simple organic compounds. Benzene is a carcinogen, with long-term exposure causing leukaemias (cancers of blood cells). - Stock Image A705/0072
Benzene concentrations in Hamilton, 2003-16 - Ministry for the Environment | | GIS Map Data - Download GIS data as Shapefile (SHP), DWG, MapInfo, CSV, Google Earth (KML).
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Cyclic polyene with six carbon atoms (benzene) is very stable, whereas cyclic polyene with four carbon atoms (cyclobutadiene) is extremely unstable. The electron-withdrawing pentafluorophenyl group of a substituted cyclobutadiene lowers the energy of the lowest unoccupied molecular orbital, greatly increasing its reactivity as a diene in Diels-Alder reactions with acetylene, ethylene and even benzene. Here we show that the reaction with benzene occurs cleanly at the relatively low temperature of 120 °C and results in the formal fragmentation of benzene into C2H2 and C4H4 units, via a unique Diels-Alder/retro-Diels-Alder reaction. This is a new example of the rare case where breaking the C-C bond of benzene is possible with no activation by a transition metal.
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Benzene has been associated with acute leukemia since 1928. If you were occupationally exposed to benzene, make sure your doctor is aware of your work history because initial symptoms of leukemia may be vague and hard to diagnose. Contact us if you have been diagnosed leukemia and were exposed to benzene in New York.
HOUSTON (AP) - National Guard troops have been called in and residents are being told to say inside after elevated levels of benzene were detected near a Houston-area petrochemicals storage facility that caught fire this week.
Air pollution, containing high-level of ultrafine particles (UFP) and benzene, is a prominent environmental health problem in many cities of the World. We investigated the level of oxidative DNA damage in mononuclear blood cells (MNBC) by the comet assay as DNA strand breaks (SB) and formamidopyrimidine DNA glycosylase (FPG) sensitive sites in residents from three urban locations in Cotonou, Benin (taxi-moto drivers, subjects living near roads with intense traffic and suburban residents) and rural residents. Exposure was characterized by urinary excretion of S-phenylmercapturic acid (S-PMA), a biomarker of benzene exposure, and by ambient UFP. There were clear stepwise gradients with respect to ambient UFP, S-PMA excretion and oxidative DNA damage with rural subjects , suburban subjects , residents living near highly trafficed roads,taxi-moto drivers. Polymorphisms in glutathione peroxidase (GPX), NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferase (GST) genes were assessed for ...
Long-term benzene exposure is linked to leukemia and other blood disorders. Learn about the risk factors to prevent exposure to this harmful substance.
Would you like to know more about Benzene exposure and what causes it? Click here to read more about benezene exposure and what to do if exposed.
If you have been diagnosed with a disease that may have been caused by benzene exposure, turn to Rosenbaum & Rosenbaum, P.C. 212-514-5007.
Article Economic Evaluation of Air Quality Targets for CO and Benzene. The study is to identify and estimate the costs and benefits of meeting ambient air quality standards for carbon monoxide (CO) and benzene in the EU. The study should take the ran...
High Quality Content by WIKIPEDIA articles! Benzene, or benzol, is an organic chemical compound with the molecular formula C6H6. It is sometimes abbreviated Ph-H. Benzene is a colorless and highly flammable liquid with a sweet smell and a relatively high melting point. Because it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and precursor in the production of drugs, plastics, synthetic rubber, and dyes. Benzene is a natural constituent of crude oil, and may be synthesized from other compounds present in petroleum. Benzene is an aromatic hydrocarbon and the second annulene, a cyclic hydrocarbon with a continuous pi bond.. ...
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Benzene enters cells and damages DNA material. As well, benzene is known to cause harmful effects on bone marrow and it can cause a decrease in red blood cells, leading to anemia. Women exposed to the chemical can suffer irregular menstrual periods and a decrease in the size of their ovaries. The FDA has regulated these solvents for decades, but workers, populations living near industrial sources of benzene and butadiene emissions, and the general public continue to be exposed these deadly chemicals. Benzene is still present in a number of products, from petroleum solvents to soft drinks ...
Field Validation of Technologies for Anaerobic Benzene and Alkylbenzene Bioremediation," is funded through the Genome Canada Genomic Applied Partnership Program (GAPP). This project builds upon earlier research that successfully developed commercial volumes of an anaerobic benzene-degrading bioaugmentation culture and associated genomics-based monitoring tools for tracking benzene bioremediation. The goal of this project is the commercialization of an expanded range of anaerobic bioaugmentation cultures for the treatment of BTEX at contaminated sites across Canada.. Additional funding partners include the Ontario Ministry of Economic Development, Job Creation and Trade, SiREM, Imperial Oil Limited, Federated Co-operatives Limited, Alberta Innovates, and Mitacs.. ...
TY - JOUR. T1 - Campionamento per diffusione di benzene presente nelle urine.. AU - Ghittori, S.. AU - Cocheo, V.. AU - Imbriani, M.. PY - 1997. Y1 - 1997. N2 - Benzene is a widely diffuse solvent; in the industrial environment benzene is currently present at concentrations of ppm. A valid method of biological monitoring that is easy to perform is need for assessing occupational and non-occupational exposures. A new method has been developed to evaluate low concentrations of benzene in urine samples by means of a diffusion sampling. The solvent is absorbed from the urine surface and concentrated on an absorbent substrate (Tenax) that is placed inside the vial. The solvent is thermically desorbed from Tenax and injected into a column (Thermal Tube Desorber-Supelco; 250 degrees C thermal flash; borosilicate capillary glass-column SPB-I 60 m length, 0.75 mm I.D., 1 micron film thickness; GC Dani 8580-FID). The method, which had not been previously employed for the determination of volatile organic ...
TY - GEN. T1 - Modeling of benzene with ethylene alkylation. AU - Khlebnikova, Elena. AU - Dolganova, Irena. AU - Ivashkina, Elena. AU - Koshkin, Stanislav. PY - 2016/4/19. Y1 - 2016/4/19. N2 - The paper considers the benzene alkylation with ethylene model development with the use of zeolite catalyst. A list of reactions occurring in the alkylation reactor was made and the thermodynamic possibility of determination of these reactions by the change of Gibbs energy was defined. The paper presents the hydrocarbons transformation scheme, which includes the grouping of components on the basis of their reactivity and the degrees of compensation values of the corresponding reactions. Drawing on the obtained data the authors developed the kinetic model of the alkylation of benzene with ethylene.. AB - The paper considers the benzene alkylation with ethylene model development with the use of zeolite catalyst. A list of reactions occurring in the alkylation reactor was made and the thermodynamic ...
A cunningly modified ring of boron and nitrogen atoms is the closest inorganic analog of benzene yet created, its creators say (Angew. Chem., Int. Ed. 2020, DOI: 10.1002/anie.201915790). The first inorganic version of benzene was reported almost a century ago. Borazine (B3N3H6) contains a flat six-membered ring and a delocalized cloud of six π electrons but is only moderately aromatic. Since borazines discovery, a handful of other inorganic benzenes have been created, none of which seem to have much aromaticity. Rei Kinjo and Kei Ota at Nanyang Technological University have now created a 1,4,2,3,5,6-diazatetraborinine derivative that is much more benzene-like than its predecessors. The blue solid is a valence isomer of benzene, with each ring atom bearing only one substituent. Unlike borazines alternating pattern of elements, diazatetraborinines ring includes four boron atoms that sit in pairs and bond to either chlorine or trimethylphosphine. X-ray crystallography shows that the molecule is ...
Asia Pacific was the largest consumer of benzene & its derivatives and this trend is anticipated to remain same in the next few years. Consumption patterns in Asia Pacific are showing upward trend owing to shift of manufacturing facilities to China and India due to availability of cheap labour and raw material. China and Japan were largest consumer of benzene in this region while, South Korea and India are expected to grow at a higher pace. Rising demand from automobile, coatings, textiles and other industries is expected to drive the benzene & its derivatives market in Asia Pacific. In addition, increasing production capacities in specialty chemicals are expected to fuel the market growth. Consumption for benzene & its derivatives in rest of the world was low but it is expected to grow at a moderate pace followed by Asia Pacific. North America is expected to grow at a substantial rate owing to demand from construction and textiles industry. Demand from Europe was low comparatively and is ...
This reads in the structures of P3HT (thiophene_R_hexane) with five repeat units and replicates it randomly in space 10 times. Similarly for C60 is replicated randomly in space 10 times to make a 1:1 mixed phase. Benzene is treated as a solvent and is replicated on a grid for faster replicatation. For each benzene added the distance between the benzene and the already added P3HT and C60 molecules is calculated, and if benzene is within the cutoff it is not added to the grid point. The new mixed phase LAMMPS input file:. ...
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Development policies and plans are also discussed as well as manufacturing processes and cost structures. Benzene Sulfonic Acid market report also states import/export, supply and figures as well as cost, price, revenue and gross margin by regions (United States, EU, China and Japan), and other regions can be added.. Ask for Discount @ http://www.360marketupdates.com/enquiry/request-discount/10324132. Then, Benzene Sulfonic Acid market report focuses on major leading industry players with information such as company profiles, product picture and specification, capacity, production, price, cost, revenue and contact information. Upstream raw materials, and downstream consumers analysis is also carried out. Whats more, the Benzene Sulfonic Acid industry development trends and marketing channels are analysed.. For each player, product details, capacity, price, cost, gross and revenue numbers are given. Their contact information is provided for better understanding.. Purchase Benzene Sulfonic Acid ...
Import Data And Price Of Diethyl Methyl Benzene , www.eximpulse.com Eximpulse Services will provide you the latest and relevant market intelligence reports of Diethyl Methyl Benzene Import Data. You can find live data of maximum number of ports of India which is based on updated shipment data of Indian Customs. Only previous two days data will be seen on website. You can use this Diethyl Methyl Benzene import data for multiple kinds of analysis; lets say Import price, Quantity, market scenarios, Price trends, Duty optimization and many more. You can go through some of the sample shipment records for Diethyl Methyl Benzene import data mentioned above. Here on Eximpulse Services you will get all kind of free sample as well as detailed reports of Export/ Import data as per your requirement. To get in touch for any kind of enquiry related to free sample or detailed report contact on +91-120-408-4957, +91-120-408-4958,+91-120-428-4019.. Data post 2012 as per Notification No.18/2012 - Customs(N.T.) ...
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Import Data And Price Of Mono Chloro Benzene , www.eximpulse.com Eximpulse Services will provide you the latest and relevant market intelligence reports of Mono Chloro Benzene Import Data. You can find live data of maximum number of ports of India which is based on updated shipment data of Indian Customs. Only previous two days data will be seen on website. You can use this Mono Chloro Benzene import data for multiple kinds of analysis; lets say Import price, Quantity, market scenarios, Price trends, Duty optimization and many more. You can go through some of the sample shipment records for Mono Chloro Benzene import data mentioned above. Here on Eximpulse Services you will get all kind of free sample as well as detailed reports of Export/ Import data as per your requirement. To get in touch for any kind of enquiry related to free sample or detailed report contact on +91-120-408-4957, +91-120-408-4958,+91-120-428-4019.. Data post 2012 as per Notification No.18/2012 - Customs(N.T.) and does not ...
Last week, despite bearish upstream energy values, benzene prices climbed higher in Asia. The price rise was supported by tight regional product availability and stronger downstream SM rates.Gains recorded in benzene values in the U.S., further pushed price higher in the region. On Friday, benzene prices were assessed at the USD 625/mt FOB Korea levels, a week on week gain of USD 15/mt. Downstream SM prices were assessed higher at the USD 805/mt FOB Korea levels, a sharp rise of USD 25/mt from the previous week.In the USA, benzene prices on Thursday were at the 243.90 cents/gallon FOB US Gulf mark, a week on week increase of 4.95 cents/gallon.
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Average benzene home and personal levels in six monitoring campaigns varied between 6.0-13.4 and 13.1-24.6 μg/m3, respectively. Urban levels varied between 15.4 and 27.9 μg/m3 with an annual mean of 20.4 μg/m3. Wind speed seems to determine largely home levels and personal exposure. Proximity to busy road holds also an important influence on indoor benzene levels. Adjusted for seasonal or climate variation, other significant prognostic factors of personal exposure were home levels, total time spent outdoors and transportation mean. Time spent outdoors explains the strong relationship between occupation and personal levels of exposure. Wind had similar effect in clearing indoor and urban pollution in Athens; lessen personal exposure and home levels about 2-2.5 μg/m3 per 1 m/s increase in speed.. ...
We have carried out a pilot case-control study of childhood leukaemia and exposure to benzene assessed by repeated individual measurements made on average 2 years after diagnosis. The pilot study included side-investigations aimed at evaluating the performance of two biological indicators of benzene exposure in children, at estimating amount and direction of a possible participation bias and at assessing the relation between estimated exposures to benzene and ELF magnetic fields.. Owing to the relatively low incidence of childhood cancers (10-15 for 100 000 person-years in the 0-14 year range in most industrialised countries), the case-control approach is the design of choice for analytical epidemiological studies about potential risk factors for these diseases. Such a study design, however, is inherently prone to measurement errors stemming from the retrospective reconstruction of the exposures of interest, and to differential participation leading to control samples not being representative of ...
Families in Nisisioken Ogale, near a Nigerian National Petroleum Company pipeline, are drinking water from wells contaminated with benzene, a known carcinogen, at levels over 900 times above UN World Health Organization guidelines.
The proposed project comprises mechanistic research to assess the biogeochemical interactions that affect bioavailability of chlorinated benzenes (CBs) during i...
ANGEWANDTE CHEMIE VOLUME 6 NUMBER 5 MAY 1 9 6 7 P A G E S 385-476 Benzene Oxide-Oxepin Valence Tautomerism BY E. VOGEL AND H. G m T H E R [*I Dedicated to Prof. R. Criegee on the occasion of his 65th birthday Benzene oxide and the potential 8x-electron system oxepin exist in valence-tautomeric equilibrium with each other, to which both components contribute to approximately the same extent. N M R spectroscopic measurements show that the equilibrium is rapidly established (activation energies of the forward and reverse reactions 9.1 and 7.2 kcal mole-1, respectively). The present knowledge of the properties of oxepinjustifies its classification as a "heterotropilidene". Benzene oxide-oxepin represents a system having fluctuating bonds, the equilibrium of which can be displaced from one extreme fo the other by means of suitable substituents. The oxide component determines the reactions of the system with most agents. With 1,6-oxido[ IO]annulene, which is formally a 2,7-bridged oxepin, the oxepin ...
For continuous monitoring of benzene at refinery fenceline locations using EPA Method 325 May be used also for other VOCs of concern including HAPs See Technical Note: Validated Uptake Rates for Benzene and Other VOCs Using the SKC Passive TD Tube (PDF)
Benzene first reacts with the reagents $\ce{CH3Cl/AlCl3}$, to attach a methyl ($\ce{CH3}$) group to the benzene ring.. Then I suggested reacting with $\ce{OH-}$. Because the methyl group is an activator, it will cause the $\ce{OH-}$ electrophile to attack either in the para or ortho positions. In this case I suggest it will attack the ortho position. Now we have two activators, hydroxyl and methyl, but because hydroxyl is a stronger activator, the position where the next molecule attacks will be controlled by the hydroxyl group.. The next electrophile that attacks is the $\ce{NO2+}$, through the reaction $\ce{HNO3/H2SO4}$, the nitro group will attack the para position of the benzene and we get our final product 2-methyl-4-nitrophenol.. However, I am not 100% sure if the methyl group should be introduced first to form toluene or the hydroxyl group to form a phenol.. ...
Directing Groups. The rate of substitution on a benzene ring is affected by what groups are already on the benzene ring. Those groups which lower the rate of electrophilic substitution is calld an activating group. Any substituent that lowers the rate (from benzene) of substitution is called a deactivating group. An important thing to know about substitution reactions on benzene is that you will NEVER get exactly what you want. You always get a mixture of what you want (a mixture of ortho/para/meta groups), and you must then use methods to separate the stuff you dont want. For instance, you may want to substitute a nitro group para from the the methyl group in the toluene. Once you have finished with the substitution reaction, only 37% of the final product will have the nitros in the para position. About 59% will have the nitro in the ortho position, while 4% will have the nitro in the para group. So when you plan out your substitutions, note what is on the benzene ring and remember that these ...
Both occupational exposure to the leukemogen benzene and in vitro exposure to its metabolite hydroquinone (HQ) lead to the induction of numerical and structural chromosome changes. Several studies have shown that HQ can form DNA adducts, disrupt microtubule assembly and inhibit DNA topoisomerase II (topo II) activity. As these are potential mechanisms underlying endoreduplication (END), a phenomenon that involves DNA amplification without corresponding cell division, we hypothesized that HQ could cause END. We measured END in the human lymphoblastoid cell line, TK6, treated with HQ (0-20 µM) and etoposide (0-0.2 µM) for 48 h. Etoposide was used as a positive control as it is a topo II poison and established human leukemogen that has previously been shown to induce END in Chinese hamster ovary cells. Both HQ and etoposide significantly induced END in a dose-dependent manner (Ptrend , 0.0001 and Ptrend = 0.0003, respectively). Since END may underlie the acquisition of high chromosome numbers by ...
Its melting point is -44 °C, which is lower than that of benzene, as a result of the reduced symmetry of the molecule compared to benzene. In contrast, the boiling points of PhF and benzene are very similar, differing by only 4 °C. It is considerably more polar than benzene, with a dielectric constant of 5.42 compared to 2.28 for benzene at 298 K.[1] ...
TY - JOUR. T1 - Ordered nanostructure of PS-b-PEO copolymer by solvent annealing with mixture of benzene/water vapor and its micropattern fabrication. AU - Kim, Tae Hee. AU - Hwang, Jiyoung. AU - Acharya, Himadri. AU - Park, Cheolmin. PY - 2010/10/1. Y1 - 2010/10/1. N2 - We investigate the effect of water/benzene co-solvent vapor on the ordering of poly(styrene-b-ethylene oxide) (PS-b-PEO) copolymer thin film on silicon substrate upon solvent annealing. In-plane cylindrical PEO microdomains were observed after exposure of benzene vapor. The addition of water vapor dominantly produced the cylindrical PEO domains aligned perpendicular to the substrate. The best ordering of the cylinders was obtained at the water fraction of approximately 0.05. The degree of ordering decreases while the periodicity of haxagonally packed PEO cylinders increases with the amount of water in the vapor mixture. The average center-to-center distance of hexagonally packed cylindrical PEO microdomains increases with the ...
A new <"http://www.yourlawyer.com/topics/overview/benzene">benzene lawsuit, a class action, alleges that a 1986 Shell Oil Company benzene spill damaged property values and ground water in Roxana, Illinois, said The Telegraph. Both BP and Shell operate refineries in the area that processed and used benzene and benzene-containing pollutants.. Benzene is a colorless liquid with a sweet odor that evaporates into the air very quickly and dissolves slightly in water. Several organizations, including the U.S. Department of Health and Human Services (DHHS), the U.S. National Toxicology Program, and the International Agency for Research on Cancer (IARC) recognize benzene as a cancer-causing chemical.. While benzene’s tolls on the body are well known and documented, this lawsuit claims that the spill caused property values to fall and blames benzene for Roxana residents being unable to sell their houses, said The Telegraph. The suit includes nine counts; no dollar amount has been specified. Shell, ...
TY - JOUR. T1 - Pore size control through benzene vapor deposition on activated carbon. AU - Kang, Hyun Uk. AU - Kim, Wun gwi. AU - Kim, Sung Hyun. PY - 2008/10/15. Y1 - 2008/10/15. N2 - Carbon adsorbents are considered as prime material to separate oxygen and nitrogen in PSA process. It is known that selectivity of carbon adsorbents can be added by adjusting pore size on the adsorbents. Among many treatment methods, chemical vapor deposition method was selected and benzene was used as a chemical agent. Activated carbons were heated at 5 °C/min and 10 °C/min in inert condition. The peak temperature at 700 °C and 800 °C was maintained while activated carbons were treated with benzene vapor. Inert condition was given as laminar and turbulent flow conditions. Pore size distribution results investigated by adsorption of various gases including CO2 (3.3 Å), n-butane (4.3 Å) and iso-butane (5.0 Å), assured of the pore constriction or heightened energy barrier on the pore opening. The nitrogen ...
But there was no accountability in place to punish Cadbury like there was for Perrier over the serious nature of this violation and it is a problem that very likely still exists today, concerned industry observers contend. For the record, the Diet Orange Crush contained 36 and 52 parts per billion (ppb) benzene in two samples taken by the Food and Drug Administration (FDA) in late 1990 when the product was pulled and another preliminary sample showed as high as 180 ppb benzene. Compare this to the 11-18 ppb benzene found in Perrier water and you can see why some are concerned Cadbury got off too easy 16 years ago ...
The report including six parts, the first part maainly introduced the product basic information; the second parts mainly analyzed the Asia Pure Benzene industry; the third part mainly analyzed the North American Pure Benzene industry; the fourth part mainly analyzed the Europe Pure Benzene industry; the fifth part mainly analyzed the market entry and investment feasibility; the sixth part was the report conclusion chapter ...
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Hence, this enzyme has one substrate, (S)-2-methylmalate, and two products, 2-methylfumarate and H2O. This enzyme belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme class is (S)-2-methylmalate hydro-lyase (2-methylfumarate-forming). Other names in common use include mesaconate hydratase, (+)-citramalate hydro-lyase, L-citramalate hydrolase, citramalate dehydratase, (+)-citramalic hydro-lyase, mesaconate mesaconase, mesaconase, and (S)-2-methylmalate hydro-lyase. This enzyme participates in c5-branched dibasic acid metabolism. In addition, the family of lyases which is also an enzyme catalyzes the breaking the elimination reaction of the variety of amounts of chemical bonds from hydrolysis (a substitution reaction ) and oxidation, which forms a new double bond or a new ring structure.[1] ...
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The plaintiff, who was born and raised within a half-mile radius of the facility, was diagnosed at age four with a specific type of childhood leukemia associated with benzene exposure. Unbeknownst to the childs family, the defendants had engaged in documented and illegal disposal methods of toxic chemicals, including benzene, for years. The improper and hazardous activities included dumping toxic waste on the ground near the childs house and contamination of a drinking water well which the childs family used.. The lawsuit, filed in the Superior Court of Athens-Clarke County, Georgia, names some of the worlds largest oil companies, including BP, Chevron, Unocal, Transmontaigne Product Services, Gulf Oil, Louis Dreyfus Highbridge Energy, LLC, Colonial Pipeline, and Plantation Pipe Line.. The family is represented by Chris Nidel of Nidel Law, PLLC in Washington, D.C., and Matt Harman of Harman Law LLC in Atlanta, Georgia.. ...
Exposure to benzene, a known human carcinogen, has been linked to serious blood diseases such as AML, MDS, lymphomas and aplastic anemia.
An environmental nonprofit has released an analysis of first-of-its-kind air monitoring data that shows benzene levels at 10 U.S. petroleum refineries exceeded limits established in an Obama-era environmental regulation. Six are in Texas.
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Benzene is a chemical widely used in a number of industries and products. Exposure to the chemical has been linked to Acute Myeloid Leukemia (AML), Myelodysplastic Syndrome (MDS), lymphomas and aplastic anemia. Many of these cases involving benzene exposure link back to the workplace. Ringler Radio host Larry Cohen and co-host, Keith Christie talk with attorney John Tomlinson, from the Beasley Allen law firm, about benzene exposure, litigation, and how exposure to benzene can be controlled, reduced or prevented.. Visit Ringler to contact a consultant in your area about structured settlements.. ...
Diagnosed with AML or MDS? Are you an Auto Mechanic or Printer? Did you work with Benzene or Solvents? Benzene causes Leukemia. Read on to learn more.
Benzene is absorbed rapidly and extensively after inhalation and ingestion. It is absorbed less extensively through intact skin; however, percutaneous absorption may...
Courtney and Jim Vostry filed a benzene lawsuit Jan. 2 in Madison County Circuit Court -- the first civil lawsuit seeking damages in excess of $50,000 this year.
This week, ShaleTest released a new study that claims shale development is polluting the air near playgrounds, but the same scientifically dubious techniques that plagued the groups previous studies once again form the core of the reports conclusions. The effort was funded by a grant from California-based clothing outfitter Patagonia, which opposes hydraulic fracturing, despite the fact that its stores are filled with items that are made from petroleum products.. Just as a bit of background, ShaleTest - which is "proudly affiliated" with the anti-fracking group Earthworks - is headed up by Calvin Tillman, a former mayor of DISH, Tex., and one of the big stars of Josh Foxs Gasland films. On several occasions, ShaleTest has teamed up with other well-known anti-fracking activists to produce "studies" just like the one released this week - and each one has been criticized for its lack of scientific integrity.. Tillmans first "report" was actually contracted out to Wolf Eagle Environmental, the ...
San Diego, CA (PRWEB) July 25, 2012 -- The media spotlight is often a double-edged sword. No one knows this better than the widow of Ricky Perrio, Diana Perrio
The progress made in developing the molecular theory of matter in the liquid state has been retarded by the circumstance that the experimental data, available for the purpose of testing theoretical conclusions, are scanty. For such a purpose the latent heat of the vapour of a suitable liquid would be particularly useful. Numerous formulae expressing the latent heat of vapours at high temperatures as a function of two or more of the physical constants of the vapour and liquid have been proposed. Some of the references to the best known of these are- Bakker (ʻZ. f. Physik. Chem., vol. 18, p. 519, 1895); Crompton (ʻProc. Chem. Soc., vol. 17, p. 61, 1901); Mills (J. Phys. Chem., vol. 6, p. 209, 1902); Dieterici (Ann. d. Physik, vol. 35, p. 220,1911; vol. 62, p. 75, 1920); Lewis (ʻPhil. Mag., vol. 25, p. 61, 1913); Appleby and Chapman (ʻJ. Chem. Soc., p. 734, 1914); Partington (ʻZ. f. Physik. Chem., vol. 88, p. 29, 1914); Albertosi (ʻJ. Chem. Phys., vol. 13, p. 379, 1915); Hammick ...
Ab initio calculations, using restricted Hartree-Fock, density-functional (DFT) and Moeller-Plesset perturbation theories, have been performed to study the cation-pi interactions between alkali cations and [7]-helicene as well as the interaction between [7]-helicene and benzene. The helical molecules two terminal benzene rings give the profile of crocodiles jaws which open up to receive the cations, exhibiting the stability of the complexes increasing in the order Na+, K+, Cs+. The binding energies in these cation-pi complexes comprise mainly electrostatic, polarization (including dispersion) and charge transfer contributions. According to DFT, the electrostatic contribution alone is 43% for Na+, 60% for K+ and 75% for Cs+. However, even DFT shows very little stabilization for the helicene-benzene complex so that this interaction between a helical and a neutral molecule cannot serve as a model for DNA-drug interactions due to very little overlap between the pi clouds of the two ...
RIKEN researchers break carbon-carbon bonds and rearrange the structure of benzene at low temperatures with a trinuclear titanium hydride complex.
Abstract: Amendment of existing standard for Occupational Exposure to Benzene. The revised standard reduces the permissible exposure limit (PEL) from 10 parts benzene per million parts of air (10 ppm) to an eight (8)-hour time-weighted average (TWA) of 1 ppm and a short-term exposure limit (STEL) of 5 ppm. Provides for methods of compliance, personal protective equipment, employee monitoring, medical surveillance, medical removal protection, communication of hazards to employees, regulated areas, and recordkeeping. The amended standard takes effect on December 10, 1987 ...
Benzene[edit]. Main article: Benzene. One VOC that is a known human carcinogen is benzene, which is a chemical found in ... Benzene evaporates into the air quickly and the vapor of benzene is heavier than air allowing the compound to sink into low- ... Benzene also has natural sources such as volcanoes and forest fires. It is frequently used to make other chemicals in the ... Benzene has also been known to contaminate food and water and if digested can lead to vomiting, dizziness, sleepiness, rapid ...
Baton Rouge Refinery benzene leak[edit]. On June 14, 2012, a bleeder plug on a tank in the Baton Rouge Refinery failed and ... ExxonMobil sent an official notification to the LDEQ saying that the leak had actually released 28,688 pounds of benzene, ... began leaking naphtha, a substance that is composed of many chemicals including benzene.[189] ExxonMobil originally reported to ...
Mesoporous aerogel - selective oxidation of benzene[edit]. Silver nanoparticles supported on aerogel are advantageous due to ... "Silver Nanoparticles in Mesoporous Aerogel Exhibiting Selective Catalytic Oxidation of Benzene in CO2 Free Air". Catalysis ... the higher number of active sites.[64] The highest selectivity for oxidation of benzene to phenol was observed at low weight ... benzene, carbon monoxide, and likely other compounds. ... 3.1.2 Mesoporous aerogel - selective oxidation of benzene. *3.1 ...
Benzene and heterocycle linked through a non-carbon[edit]. *Olanzapine. References[edit]. *^ Benzhydryl+Compounds at the US ... Benzenes linked by a non-carbon atom[edit]. *Nitrogen: promethazine, imipramine, acepromazine, chlorpromazine, fluphenazine, ... This does not include compounds where these benzenes are fused to other rings.[1] Benzhydryl can be abbreviated to CHPh2 or Bzh ... Benzhydryl compounds are compounds that are "diphenylmethane"-containing, i.e. containing two benzene rings adjoining a single ...
Benzene. Dichloromethane. Chloroform. Ether (anhydrous). Ethyl Acetate (anhydrous). Acetone (anhydrous). methanol. ethanol. ...
... (CHF-3381, V-3381) is a drug which was formerly being investigated as an anticonvulsant and neuroprotective and is now under development for the treatment of neuropathic pain and chronic cough in Europe by Vernalis and Chiesi.[1][2][3][4][5][6][7][8] It acts as a competitive, reversible, and non-selective monoamine oxidase inhibitor,[5][6][9] and as a low affinity, non-competitive NMDA receptor antagonist.[1][2][10] A pilot study of indantadol for chronic cough was initiated in October 2009 and in April 2010 it failed to achieve significant efficacy in neuropathic pain in phase IIb clinical trials.[7][8][11][12] ...
In 2001, the German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BfR) objected to the addition of isolated theanine to beverages.[39][40] The institute stated the amount of theanine consumed by regular drinkers of tea or coffee is virtually impossible to determine. While it was estimated the quantity of green tea consumed by the average Japanese tea drinker per day contains about 20 mg of the substance, there are no studies measuring the amount of theanine being extracted by typical preparation methods, or the percentage lost by discarding the first infusion. Therefore, with the Japanese being exposed to possibly much less than 20 mg per day, and Europeans presumably even less, it was the opinion of the BfR that pharmacological reactions to drinks typically containing 50 mg of theanine per 500 milliliters could not be excluded-reactions such as impairment of psychomotor skills and amplification of the sedating effects of alcohol and hypnotics.[41] In 2006, a study ...
... is generally considered a non-polar solvent. Owing to the good polarizability of the chlorine atoms, it is a superior solvent for organic compounds that do not dissolve well in hydrocarbons such as hexane. It is an excellent solvent for many organic materials and also one of the least toxic of the chlorinated hydrocarbons. Prior to the Montreal Protocol, it was widely used for cleaning metal parts and circuit boards, as a photoresist solvent in the electronics industry, as an aerosol propellant, as a cutting fluid additive, and as a solvent for inks, paints, adhesives, and other coatings. 1,1,1-Trichloroethane is also used as an insecticidal fumigant. It was also the standard cleaner for photographic film (movie/slide/negatives, etc.). Other commonly available solvents damage emulsion, and thus are not suitable for this application. The standard replacement, Forane 141 is much less effective, and tends to leave a residue. 1,1,1-Trichloroethane was used as a thinner in ...
Transcrocetinate sodium can be prepared by reacting saffron with sodium hydroxide and extracting the salt of the trans crocetin isomer from the solution.[10] John L. Gainer and colleagues have investigated the effects of transcrocetinate sodium in animal models.[10][11] They discovered that the drug could reverse the potentially fatal decrease in blood pressure produced by the loss of large volumes of blood in severe hemorrhage, and thereby improve survival.[11] Early investigations of transcrocetinate sodium suggested that it had potential applications in battlefield medicine, specifically in treatment of the many combat casualties with hemorrhagic shock.[8][11] Additional studies, carried out in animal models and in clinical trials in humans, indicated that transcrocetinate sodium might prove beneficial in the treatment of a variety of conditions associated with hypoxia and ischemia (a lack of oxygen reaching the tissues, usually due to a disruption in the circulatory system), including ...
... producing algal blooms are associated with the phenomenon of amnesic shellfish poisoning (ASP). Domoic acid can bioaccumulate in marine organisms such as shellfish, anchovies, and sardines that feed on the phytoplankton known to produce this toxin. It can accumulate in high concentrations in the tissues of these plankton feeders when the toxic phytoplankton are high in concentration in the surrounding waters. Domoic acid is a neurotoxin that inhibits neurochemical processes, causing short-term memory loss, brain damage, and, in severe cases, death in humans. In marine mammals, domoic acid typically causes seizures and tremors. Studies have shown that there are no symptomatic effects in humans at levels of 0.5 mg/kg of body weight. In the 1987 domoic acid poisoning on Prince Edward Island concentrations ranging from 0.31-1.28 mg/kg of muscle tissue were noted in people that became ill (three of whom died). Dangerous levels of domoic acid have been calculated based on cases such as the ...
Talyzin, A.V. (1997). "Phase Transition C60−C60*4C6H6 in Liquid Benzene". Journal of Physical Chemistry B. 101 (47): 9679-9681 ... Talyzin, A.V.; Engström, I. (1998). "C70 in Benzene, Hexane, and Toluene Solutions". Journal of Physical Chemistry B. 102 (34 ... Like other solvates, this one readily releases benzene to give the usual fcc C60. Millimeter-sized crystals of C60 and C. 70 ... 60 crystallises with some solvents in the lattice ("solvates"). For example, crystallization of C60 in benzene solution yields ...
Each AMPAR has four sites to which an agonist (such as glutamate) can bind, one for each subunit.[5] The binding site is believed to be formed by the N-terminal tail and the extracellular loop between transmembrane domains three and four.[16] When an agonist binds, these two loops move towards each other, opening the pore. The channel opens when two sites are occupied,[17] and increases its current as more binding sites are occupied.[18] Once open, the channel may undergo rapid desensitization, stopping the current. The mechanism of desensitization is believed to be due to a small change in angle of one of the parts of the binding site, closing the pore.[19] AMPARs open and close quickly (1ms), and are thus responsible for most of the fast excitatory synaptic transmission in the central nervous system.[17] The AMPAR's permeability to calcium and other cations, such as sodium and potassium, is governed by the GluA2 subunit. If an AMPAR lacks a GluA2 subunit, then it will be permeable to sodium, ...
Benzene is a raw material for dyes and synthetic detergents, and benzene and toluene for isocyanates MDI and TDI used in making ... benzene - the simplest aromatic hydrocarbon *ethylbenzene - made from benzene and ethylene *styrene made by dehydrogenation of ... Benzene. Butadiene. Ethylene. p-Xylene. Propylene Intermediates. 2-Ethylhexanol (2-EH). Acetic acid. Acrylonitrile (AN). ... Linear alkyl benzene (LAB). Methanol. Methyl tert-butyl ether (MTBE) Phenol. Propylene oxide. Purified terephthalic acid (PTA) ...
William T. G. Morton participated in a public demonstration of ether anesthesia on October 16, 1846 at the Ether Dome in Boston, Massachusetts. However, Crawford Williamson Long, M.D., is now known to have demonstrated its use privately as a general anesthetic in surgery to officials in Georgia, as early as March 30, 1842, and Long publicly demonstrated ether's use as a surgical anesthetic on six occasions before the Boston demonstration.[14][15][16] British doctors were aware of the anesthetic properties of ether as early as 1840 where it was widely prescribed in conjunction with opium.[17] Diethyl ether largely supplanted the use of chloroform as a general anesthetic due to ether's more favorable therapeutic index, that is, a greater difference between an effective dose and a potentially toxic dose.[18] Diethyl ether depresses the myocardium and increases tracheobronchial secretions.[19] Diethyl ether could also be mixed with other anesthetic agents such as chloroform to make C.E. mixture, or ...
Benzene. *Benzonitrile. *Buckminsterfullerene (C60, C60+, fullerene, buckyball). *C70 fullerene ...
... s are a small family of helical peptides that are derived from the venom of predatory marine snails of the genus Conus. Conantokins act as potent and specific antagonists of the N-methyl-D-aspartate receptor (NMDAR).[1] They are the only naturally-derived peptides to do so.[2] The subtypes of conantokins exhibit a surprising variability of selectivity across the NMDAR subunits, and are therefore uniquely useful in developing subunit-specific pharmacological probes.[3][4][5] Chemically, conantokins are unique in that they possess a number (generally 4 or 5) of gamma-carboxyglutamyl (Gla) residues, generated by the post-translational modification of glutamyl (Glu) residues. These Gla residues induce a conformational change from a 3 10 helix to an alpha helix on binding to Calcium.[6] In the broader scheme of genetic conotoxin classification, Conanotokins are also known as "Conotoxin Superfamily B."[7] The word "conantokin" is derived from the Filipino word antokin, meaning sleepy.[8] ...
Benzene 10μg/l 1.0 μg/l 5 μg/l " " Benzo(a)pyrene " 0.010 μg/l 0.2 μg/l 0.0028 μg/l " ...
In coordination chemistry, it serves as a tridentate ligand forming complexes such as Co(dien)(NO2)3.[5] Like some related amines, it is used in oil industry for the extraction of acid gas. Like ethylenediamine, DETA can also be used to sensitize nitromethane, making a liquid explosive compound similar to PLX. This compound is cap sensitive with an explosive velocity of around 6200 m/s and is discussed in patent #3,713,915. Mixed with unsymmetrical dimethylhydrazine it was used as Hydyne, a propellent for liquid-fuel rockets. DETA has been evaluated for use in the Countermine System under development by the U.S. Office of Naval Research, where it would be used to ignite and consume the explosive fill of land mines in beach and surf zones.[6] ...
... (ACC) is a disubstituted cyclic α-amino acid in which a three-membered cyclopropane ring is fused to the Cα atom of the amino acid. ACC plays an important role in the biosynthesis of the plant hormone ethylene.[2][3] It is synthesized by the enzyme ACC synthase ( EC 4.4.1.14) from methionine and converted to ethylene by ACC oxidase (EC 1.14.17.4).[4] ACC is also an exogenous partial agonist of the mammalian NMDA receptor.[5] ...
... is extracted from Huperzia serrata.[2] It is a reversible acetylcholinesterase inhibitor[6][7][8][9] and NMDA receptor antagonist[10] that crosses the blood-brain barrier.[11] Acetylcholinesterase is an enzyme that catalyzes the breakdown of the neurotransmitter acetylcholine and of some other choline esters that function as neurotransmitters. The structure of the complex of huperzine A with acetylcholinesterase has been determined by X-ray crystallography (PDB code: 1VOT; see the 3D structure).[12] For some years, huperzine A has been investigated as a possible treatment for diseases characterized by neurodegeneration, particularly Alzheimer's disease.[2][13] A 2013 meta-analysis found that huperzine A may be efficacious in improving cognitive function, global clinical status, and activities of daily living for individuals with Alzheimer's disease. However, due to the poor size and quality of the clinical trials reviewed, huperzine A should not be recommended as a treatment for ...
Benzene 1.1[1] Toxic, flammable. Liquid oxygen 2.4 Cryogenic. Highly flammable with combustible materials. ...
Glutamate is the most abundant excitatory neurotransmitter in the vertebrate nervous system.[21] At chemical synapses, glutamate is stored in vesicles. Nerve impulses trigger release of glutamate from the presynaptic cell. Glutamate acts on ionotropic and metabotropic (G-protein coupled) receptors.[21] In the opposing postsynaptic cell, glutamate receptors, such as the NMDA receptor or the AMPA receptor, bind glutamate and are activated. Because of its role in synaptic plasticity, glutamate is involved in cognitive functions such as learning and memory in the brain.[22] The form of plasticity known as long-term potentiation takes place at glutamatergic synapses in the hippocampus, neocortex, and other parts of the brain. Glutamate works not only as a point-to-point transmitter, but also through spill-over synaptic crosstalk between synapses in which summation of glutamate released from a neighboring synapse creates extrasynaptic signaling/volume transmission.[23] In addition, glutamate plays ...
... has been used since the 1970s in Australia as an emergency analgesic for short-term use, mostly by the Australian and New Zealand Defence Forces,[13] the Australian ambulance services,[10][35][36] and since 2018 by some Emergency medical services in Germany.[57] All of the currently used volatile anesthetic agents are organofluorine compounds. Aside from the synthesis of Freon (Thomas Midgley, Jr. and Charles F. Kettering, 1928)[58] and the discovery of Teflon (Roy J. Plunkett, 1938),[59] the field of organofluorine chemistry had not attracted a great deal of attention up to 1940 because of the extreme reactivity of elemental fluorine, which had to be produced in situ for use in chemical reactions. The development of organofluorine chemistry was a spin-off from the Manhattan Project, during which elemental fluorine was produced on an industrial scale for the first time. The need for fluorine arose from the need to separate the isotope 235U from 238U because the former, present in ...
benzene. 2.3. 298 diethyl ether. 4.3. 293 tetrahydrofuran (THF). 7.6. 298 dichloromethane. 9.1. 293 ...
NAAG is catabolized via NAAG peptidase activity. Two enzymes with NAAG peptidase activity have been cloned, glutamate carboxypeptidase II and glutamate carboxypeptidase III. These enzymes mediate the hydrolysis of NAAG to NAA and glutamate. Their inhibition can produce therapeutic benefits. Two main types of inhibitors of this enzyme are known: compounds related to 2-(phosphonomethyl)pentanedioic acid (2-PMPA) and urea-based analogs of NAAG, including ZJ43, ZJ17, and ZJ11. In rat models, ZJ43 and 2-PMPA reduce perception of inflammatory and neuropathic pain when administered systemically, intracerebrally, or locally, suggesting that NAAG modulates neurotrasmission in pain circuits via mGlu3 receptors. The inhibition of NAAG hydrolysis increases the concentration of NAAG in the synaptic space analogous to the effects of SSRIs in increasing the concentration of serotonin. This elevated NAAG gives greater activation of presynaptic mGluR3 receptors, which decrease release of transmitter (glutamate) ...
Benzene derivatives synonyms, Benzene derivatives pronunciation, Benzene derivatives translation, English dictionary definition ... of Benzene derivatives. n. A colorless, flammable, toxic, liquid aromatic hydrocarbon, C6H6, derived from petroleum and used in ... benzene. (redirected from Benzene derivatives). Also found in: Thesaurus, Medical, Encyclopedia.. Related to Benzene ... benzene formula, benzene nucleus, benzene ring, Kekule formula - a closed chain of 6 carbon atoms with hydrogen atoms attached ...

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  • Useful search terms for benzene include "benzol" and "phenyl hydride. (cdc.gov)
  • Phenyl groups are closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound to serve as a functional group. (wikipedia.org)
  • Monosubstituted phenyl groups (that is, disubstituted benzenes) are associated with electrophilic aromatic substitution reactions and the products follow the arene substitution pattern. (wikipedia.org)
  • Commercial refined benzene-535 is free of hydrogen sulfide and sulfur dioxide, but contains a maximum of 1 ppm thiophene and a maximum of 0.15% nonaromatics. (cdc.gov)
  • Refined nitration-grade benzene is free of hydrogen sulfide and sulfur dioxide. (cdc.gov)
  • citation needed] The proposed mechanism begins with hydrogen abstraction by the hydroxyl radical, which itself is produced by the Cu2+-catalysed reduction of dioxygen by ascorbic acid: Other factors that affect the formation of benzene are heat and light. (wikipedia.org)
  • It is an aromatic compound and a derivative of benzene, where benzene's six hydrogen atoms have each been replaced by a methyl group. (wikipedia.org)
  • With hydrogen chloride it forms an adduct, whereas benzene is unreactive toward HCl. (wikipedia.org)
  • It will react with any hydrogen donor such as 1,4-cyclohexadiene which converts to benzene. (wikipedia.org)
  • Benzene is found in products that are made from coal and petroleum. (cdc.gov)
  • Benzene is not to be confused with benzine, which is not a pure chemical compound but a mixture of petroleum hydrocarbons used as a solvent and a fuel. (encyclopedia.com)
  • Benzene occurs so abundantly in and is obtained so easily from coal tar and petroleum that there is virtually no reason to make it synthetically. (encyclopedia.com)
  • Although benzene had been recognized as a component of petroleum for many years, it was not produced commercially from that source until the beginning of World War II . (encyclopedia.com)
  • Benzene is a petroleum product, originally manufactured from coal tar that is used as a component in multiple industrial and consumer products. (prweb.com)
  • Benzene is a clear, liquid, petroleum-based chemical that has a sweet smell. (medlineplus.gov)
  • Today, benzene is made mostly from petroleum. (cdc.gov)
  • Benzene was first commercially recovered from light oil derived from coal tar in 1849 and from petroleum in 1941 (IARC 1982a). (cdc.gov)
  • To meet this demand, benzene was produced by the petroleum and petrochemical industries by recovery from reformat and liquid byproducts of the ethylene manufacturing process (Fruscella 1992). (cdc.gov)
  • Currently, benzene is commercially recovered from both coal and petroleum sources. (cdc.gov)
  • More than 98% of the benzene produced in the United States is derived from the petrochemical and petroleum refining industries (OSHA 1987). (cdc.gov)
  • If you work in an industry that uses benzene, please read chemical labels and the accompanying Safety Data Sheet for hazard information. (cdc.gov)
  • Benzene causes harmful effects on the bone marrow and can cause a decrease in red blood cells leading to anemia. (cdc.gov)
  • Animal studies have shown low birth weights, delayed bone formation, and bone marrow damage when pregnant animals breathed benzene. (cdc.gov)
  • Benzene is a carcinogen that also damages bone marrow and the central nervous system. (ebi.ac.uk)
  • This discussion will consider mechanisms by which benzene produces decrements in bone marrow function, alters the production of cytokines, and impairs the hematopoietic system. (springer.com)
  • Various industries use benzene to make other chemicals, such as styrene (for Styrofoam® and other plastics), cumene (for various resins), and cyclohexane (for nylon and synthetic fibers). (cdc.gov)
  • During catalytic reforming, cycloparaffins (also known by the obsolescent term 'naphthenes') such as cyclohexane, methyl cyclohexane, and dimethylcyclohexane are converted to benzene by isomerization, dehydrogenation, and dealkylation, and paraffins in naphtha (such as hexane) are converted to benzene by cyclodehydrogenation. (cdc.gov)
  • This chapter provides the diffusion coefficient of benzene in cyclohexane at different concentrations measured using Taylor dispersion technique, Rayleigh interferometry, open ended capillary, NMR spin echo pulse gradient, NMR spin echo field gradient, Gouy interferometry, forced Rayleigh scattering, diaphragm cell and closed capillary. (springer.com)
  • Winkelmann J. (2018) Diffusion coefficient of benzene in cyclohexane. (springer.com)
  • The most common chemical property of benzene is that it undergoes substitution reactions. (encyclopedia.com)
  • Researchers at Cornell University have traced pathways from benzene to nanothreads, which may involve a series of organic [4+cycloaddition reactions along stacks of benzene molecules, followed by further reaction of unsaturated bonds. (wikipedia.org)
  • In most of its reactions, it resembles benzene. (wikipedia.org)
  • HSDB 2007 aOdor threshold values considered by AIHA (1989) to be acceptable based on review of peer-reviewed reports of odor thresholds for benzene (range 0.78-100 ppm). (cdc.gov)
  • Benzene can cause blood cancers like leukemia. (cdc.gov)
  • Implications for benzene induced leukemia and the relationship to chromosome damage will be examined. (springer.com)
  • Leukemia in shoe-workers exposed chronically to benzene. (cdc.gov)
  • Benzene has also been associated with acute non-lymphocytic leukemia in humans, and aplastic anemia may be an early indicator of developing acute non-lymphocytic leukemia in some cases. (cdc.gov)
  • Benzene causes leukemia, particularly Acute Myeloid Leukemia or Acute Non-Lymphocytic Leukaemia (AML & ANLL) and is associated with other blood cancers. (mnn.com)
  • Leukemia in benzene workers. (cdc.gov)
  • The development of leukemia in benzene (71432) workers was investigated. (cdc.gov)
  • Pliofilm workers exposed to benzene had an estimated 10 fold risk of dying from myelogenous and monocytic leukemia. (cdc.gov)
  • Benzene is known to cause leukemia and other human blood disorders. (washingtonpost.com)
  • Reuters Health) - Traffic pollution near the home - and specifically, benzene in the air - increases the risk of one type of childhood leukemia, according to a nationwide study in France. (reuters.com)
  • There seems to be a stronger link between benzene and leukemia in Europe than in the U.S., though it is unclear why, he said. (reuters.com)
  • Though benzene levels have sharply decreased in Europe in recent years, and the levels in the current study are largely well below European regulations, childhood leukemia cases have not decreased, Vinceti said. (reuters.com)
  • The storage, transportation, distribution or sale of benzene or liquid mixtures containing more than 0.1 percent benzene in intact containers or in transportation pipelines while sealed in such a manner as to contain benzene vapors or liquid, except for the provisions of 29 CFR 1910.1200 as incorporated into this section and the emergency provisions of paragraphs (g) and (i)(4) of this section. (osha.gov)
  • It includes benzene contained in liquid mixtures and the benzene vapors released by these liquids. (osha.gov)
  • Yet Dow, one of the nation's largest users of benzene, withheld the potentially controversial findings last summer during a series of federal hearings to set a new standard for workers exposed to benzene. (washingtonpost.com)
  • and equally, going under its alternative name of benzine, it should not be confused with benzene. (wikipedia.org)
  • After the development of valence bond theory in 1928, benzene was described primarily using its two major resonance contributors, the two Kekulé structures. (wikipedia.org)
  • After Kekulé's proposal for benzene structure in 1865, Thiele suggested a "Partial Valence Hypothesis", which concerned double and triple carbon-carbon bonds with which he explains their particular reactivity. (wikipedia.org)
  • A pair of valence tautomers with formula C6H6O are benzene oxide and oxepin. (wikipedia.org)
  • A computational study of the valence isomers of benzene and their group V hetero analogs" (PDF). (wikipedia.org)
  • In 1931 he generalized his analysis by formulating both valence bond (VB) and molecular orbital (MO) descriptions of benzene and other cycloconjugated hydrocarbons. (wikipedia.org)
  • They later synthesized perfluorohexamethylbicyclopropenyl (5) to flesh out the first complete set of benzene valence isomers. (wikipedia.org)
  • It is insoluble in water, but soluble in organic solvents including benzene and ethanol. (wikipedia.org)
  • Individuals employed in industries that make or use benzene, or products containing benzene, are probably exposed to the highest concentrations of atmospheric benzene. (cdc.gov)
  • Table 5-1 lists the facilities in each state that manufacture or process benzene, the intended use, and the range of maximum amounts of benzene that are stored on site. (cdc.gov)
  • What happens to benzene when it enters the environment? (cdc.gov)
  • For more information on what happens to benzene after it gets into the environment, see Chapters 5 and 6. (cdc.gov)
  • Emergency means any occurrence such as, but not limited to, equipment failure, rupture of containers, or failure of control equipment which may or does result in an unexpected significant release of benzene. (osha.gov)
  • It was proposed by Adolf Karl Ludwig Claus in 1867 as a possible structure for benzene at a time when the structure of benzene was still being debated. (wikipedia.org)
  • Friedrich Kekulé proposes a ring structure for benzene. (wikipedia.org)
  • It is not known whether benzene will affect fertility in men. (cdc.gov)
  • Small quantities of benzene are also produced from destructive distillation of coal used for coke manufacture. (cdc.gov)
  • This data, they say, indicates that benzene exposures to the Dow workers studied were consistently below 10 ppm. (washingtonpost.com)
  • 1984. Depression in B- and T-lymphocyte mitogen- induced blastogenesis in mice exposed to low concentrations of benzene. (cdc.gov)
  • The Department of Health and Human Services (DHHS) has determined that benzene is a known carcinogen. (cdc.gov)
  • Benzene is also a known carcinogen according to the U.S. Department of Health and Human Services National Toxicology Program. (prweb.com)
  • It was contaminated with benzene, a carcinogen. (wikipedia.org)
  • For example, it can be used to prepare (bis(trifluoroacetoxy)iodo)benzene (phenyliodine(III) bis(trifluoroacetate), PIFA) by heating in trifluoroacetic acid: PIFA can be used to carry out the Hofmann rearrangement under mildly acidic conditions, rather than the strongly basic conditions traditionally used. (wikipedia.org)
  • Benzene was first synthesized by Mitscherlich in 1833 by distilling benzoic acid with lime. (cdc.gov)
  • The benzene forms from decarboxylation of the preservative benzoic acid in the presence of ascorbic acid (vitamin C) and metal ions (iron and copper) that act as catalysts, especially under heat and light. (wikipedia.org)
  • The major cause of benzene in soft drinks is the decarboxylation of benzoic acid in the presence of ascorbic acid (vitamin C, E300) or erythorbic acid (a diastereomer of ascorbic acid, E315). (wikipedia.org)
  • In 1993, research showed how benzene can form from benzoic acid in the presence of vitamin C. In the summer of 1998, a number of well known soft drinks manufacturers had to withdraw large quantities of their products from sale after benzene contamination in some production plants was discovered. (wikipedia.org)