A process for the preparation of polyolefin which comprises polymerizing or copolymerizing olefin in the presence of a catalyst for olefin polymerization comprising (A) a metallocene compound of a transition metal selected from the Group IVB of the periodic table, and (B) an organoaluminum oxy-compound; wherein the organoaluminum oxy-compound (B) is added to the polymerization system in the form of a slurry in an aliphatic hydrocarbon or alicyclic hydrocarbon, and the polymerization is carried out in the presence of the aliphatic hydrocarbon diluent or an alicyclic hydrocarbon diluent having a boiling point below 100 C. In an embodiment of the invention a polymer solution containing the resulting polyolefin obtained from the polymerization process is fed to a separation zone kept at a temperature of not lower than the upper cloud point of the polymer solution to separate the polymer solution into a lower phase portion containing the polyolefin in a high concentration and an upper phase portion, so as
This chapter provides an update on the current knowledge about anaerobically hydrocarbon-degrading microorganisms, the reactions involved, and recent insights into the underlying genetics and regulatory mechanisms, and it describes the suitability of growth studies with crude oil as model systems. However, anoxic conditions prevail in many natural environments, such as soils, groundwater aquifers, freshwater and marine sediments, and oil reservoirs. Early reports of the anaerobic oxidation of alkylbenzenes in microcosms and enrichment cultures and in situ biodegradation of crude oil in anoxic reservoirs provided evidence that anaerobic hydrocarbon oxidation indeed occurred. Anaerobic hydrocarbon oxidation can also be coupled to phototrophic energy conservation, as was demonstrated with the toluene-degrading Blastochloris sulfoviridis ToP1. During anaerobic growth with crude oil, strain HxN1 formed succinate derivatives of C4 to C8 n-alkanes and alicyclic hydrocarbons. Identification of
The C-O and C-S bonds break in the side chains of aromatic and alicyclic hydrocarbons. The content of primary (Cp) and the sum of secondary and quaternary (Csq) carbons was increased, while the content of tertiary (Ct) and aromatic carbons (Car) declined. The high-molecular poly-alicyclic and polyaromatic components had lost the straight and branched aliphatic hydrocarbons, and then were transformed into coke like substance -- carbene-carboids.
METHYLCYCLOHEXANE (ALICYCLISCHE KOHLENWASSERSTOFFE); DEHYDRIERUNG (CHEMISCHE REAKTIONEN); CHEMISCHE KINETIK; WASSERSTOFF (BRENNSTOFFTECHNOLOGIE); MODELLE UND MODELLUNTERSUCHUNG (TECHNISCHE CHEMIE UND VERFAHRENSTECHNIK); METHYL CYCLOHEXANES (ALICYCLIC HYDROCARBONS); DEHYDROGENATION (CHEMICAL REACTIONS); CHEMICAL KINETICS; HYDROGEN (FUEL TECHNOLOGY); MODELS AND MODEL ANALYSIS (CHEMICAL TECHNOLOGY AND PROCESS ENGINEERING ...
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When I got this gorgeous pendant from LeAnn of Summers Studio, I instantly thought of flowers at night, against the dreamy dark blue sky. They seem to dance and have a life of their own. I strung them against browns (twigs, stems , and mulch), and blues of the highlights that bounce off the petals by the light of the moon ...
The active oxygen content of the non-cyclic peroxides used was measured by placing 20 ml of glacial acetic acid in a 200 ml round-bottomed flask fitted with a ground glass joint and an inlet tube for nitrogen gas. Nitrogen gas was then passed over the surface of the liquid. After 2 minutes, 4 ml of 770 g/l potassium iodide solution was added, and a sample containing approximately 1.5 meq of active oxygen was added to the reaction mixture with mixing. The reaction mixture was allowed to stand for at least 1 minute at 25*C at S^C. The reaction mixture was then nitrated with a 0.1 N sodium thiosulfate solution to colourless end point, with 3 ml of 5 g/l starch solution being end towards the end of the titration. A blank should be run alongside this titration. Non-cyclic active oxygen can be calculated as indicated above. The amount of cyclic ketone peroxide active oxygen equals the total amount of active oxygen minus the non-cyclic active oxygen ...
Graduated from the University of York in 2014. During her placement year at AstraZeneca she worked on the manufacture of chiral amines via catalytic and flow processing methods. She also undertook a placement at the University of Nottingham looking at the synthesis and characterisation of materials which promote stem cell attachment for biomedical applications. She is currently working under the supervision of Profs. Jonathan Clayden and Kevin Booker-Milburn on the development of methodology for the ring-expansion of nitrogen heterocycles via aryl and vinyl migrations ...
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Hydrocarbon exposure has been shown to play an important role in the development of renal dysfunction in several occupational settings. In this study, renal screening was performed in a group of paint sprayers with exposure to hydrocarbon-based paints, recruited from a car manufacturing plant where personal protective equipment was widely used. The hydrocarbon exposure scores and various markers of renal injury were compared between these subjects and a group of paint sprayers from a previous study who did not use personal protective equipment regularly. Cumulative hydrocarbon exposure scores were calculated from a validated questionnaire. Serum creatinine, urinary total protein, albumin, transferrin, retinol-binding protein, and N-acetylglucosaminidase were evaluated, Both groups experienced heavy hydrocarbon exposure but sprayers who regularly used personal protective equipment had significantly reduced exposure scores due to improved skin and respiratory protection. A significant number of ...
General Information: Country: Germany; Isolation: Anaerobic sewage sludge; Temp: Mesophile. Alicycliphilus denitrificans is able to degrade cyclohexanol and other alicyclic compounds under denitrifying conditions. ...
Naming Ketones - This Leah4sci tutorial video shows you how to name molecules containing a carbonyl in the middle of the chain using my puzzle piece approach to IUPAC nomenclature. Naming examples include simple and substituted ketones, multiple carbonyls and cyclic ketones. Part of a nomenclature Video Series!
Min.medicin.dk er en hjemmeside om medicin, sygdomme, undersøgelser og behandling skrevet i et let tilgængeligt sprog. Oplysningerne er målrettet dig, der er patient, pårørende eller ansat i sundhedssektoren. Min.medicin.dk er et arbejdsredskab, som anvendes af sosu-assistenter, sosu-hjælpere og andet personale, som arbejder i plejesektoren, på bosteder og lignende ...
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Cyclohexanone is an aliphatic cyclic ketone. Cyclohexanone derivatives have potent pharmacological activity in the treatment of a broad spectrum of medical conditions (Puetz et al., 2003). The cyclohexanone moiety constitutes an important structural feature in several anti-inflammatory, analgesic, local anesthetic and antihistaminic drugs (Rajveer et al., 2010). As part of our studies in this area (Fatima et al., 2013; Hema et al., 2006), we have undertaken a single-crystal structure determination of the title compound.. In the title compound, Fig. 1, the cyclohexene ring (C9-C14) adopts an envelope conformation with atom C13 as the flap: puckering parameters (Cremer & Pople, 1975) are Q = 0.464 (3) Å, θ = 52.3 (4) °, and ϕ = 232.2 (4) °. Its mean plane makes a dihedral angle of 7.20 (12)° with the benzene ring (C1-C6).. In the crystal, hydrogen bonded chains running along the a-axis direction are generated by connecting neighbouring molecules via C-H···O hydrogen bonds (Table 1 and ...
Bill Evans (organometallics, not jazz) previously explored this reagent over a decade ago, marketing it as a souped-up SmI2 / HMPA. His study looked at cyclic ketones, which formed adducts with primary iodides in less than a minute with a healthy dose of TmI2(DME). Despite these exciting early results, it appears that thulium took a back burner to the samarium craze of the mid-00s, and only now gets its chance in the limelight ...
Min.medicin.dk er en hjemmeside om medicin, sygdomme, undersøgelser og behandling skrevet i et let tilgængeligt sprog. Oplysningerne er målrettet dig, der er patient, pårørende eller ansat i sundhedssektoren. Min.medicin.dk er et arbejdsredskab, som anvendes af sosu-assistenter, sosu-hjælpere og andet personale, som arbejder i plejesektoren, på bosteder og lignende ...
Pro.medicin.dk er en hjemmeside og database, der indeholder information om lægemidler og behandlingsvejledninger til læger, farmaceuter og andre sundhedsprofessionelle. Al information er skrevet på fagsprog. Vil du gerne læse information om medicin og behandling, der ikke er på fagsprog, så besøg min.medicin.dk. ...
Pro.medicin.dk er en hjemmeside og database, der indeholder information om lægemidler og behandlingsvejledninger til læger, farmaceuter og andre sundhedsprofessionelle. Al information er skrevet på fagsprog. Vil du gerne læse information om medicin og behandling, der ikke er på fagsprog, så besøg min.medicin.dk. ...
Pro.medicin.dk er en hjemmeside og database, der indeholder information om lægemidler og behandlingsvejledninger til læger, farmaceuter og andre sundhedsprofessionelle. Al information er skrevet på fagsprog. Vil du gerne læse information om medicin og behandling, der ikke er på fagsprog, så besøg min.medicin.dk. ...
Linear hybrid block copolymers with well controlled molecular weights and narrow polydispersities were synthesized viaring-opening metathesis polymerization (ROMP) followed by ring-opening polymerization of amino acidN-carboxyanhydrides.
Pro.medicin.dk er en hjemmeside og database, der indeholder information om lægemidler og behandlingsvejledninger til læger, farmaceuter og andre sundhedsprofessionelle. Al information er skrevet på fagsprog. Vil du gerne læse information om medicin og behandling, der ikke er på fagsprog, så besøg min.medicin.dk. ...
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The cure kinetics of polydicyclopentadiene (pDCPD) prepared by ring-opening metathesis polymerization with three different concentrations of Grubbs catalyst was examined using differential scanning calirimetry (DSC). The experimental data were used to test several different phenomenological kinetic models. The data are best modeled with a "model-free" isoconversional method. This analysis reveals that the activation energy increases significantly for degree of cure greater than 60%. Catalyst concentration is shown to have a large effect on the cure kinetics ...
SWISS-MODEL Repository entry for A1B2L0 (PANB_PARDP), 3-methyl-2-oxobutanoate hydroxymethyltransferase. Paracoccus denitrificans (strain Pd 1222)
Article Chronic hydrocarbon exposure of harlequin ducks in areas affected by the Selendang Ayu oil spill at Unalaska Island, Alaska. The authors evaluated chronic exposure of harlequin ducks (Histrionicus histrionicus) to hydrocarbons associated with...
p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.,/p> ,p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.,/p> ,p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).,/p> ,p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x,sup>64,/sup> + x,sup>4,/sup> + x,sup>3,/sup> + x + 1. The algorithm is described in the ISO 3309 standard. ,/p> ,p class="publication">Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.,br /> ,strong>Cyclic redundancy and other checksums,/strong>,br /> ,a href="http://www.nrbook.com/b/bookcpdf.php">Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993),/a>),/p> Checksum:i ...
Accurate and robust monitoring of product and reactants in a complex bioconversion stream is essential for the development of effective process control strategies. To monitor a microbially-catalysed Baeyer-Villiger bioconversion of a cyclic ketone to an optically pure lactone, a near infrared (NIR) spectroscopic method has been developed. The reaction, catalysed by cyclohexanone monooxygenase from Acinetobacter calcoaceticus (expressed in Escherichia coli) is characterised by substrate (ketone) and product (lactone) inhibition at relatively low concentrations. Quantitative multivariate calibration of a NIR spectrophotometer for ketone and lactone resulted in a standard error of prediction (SEP) at-line of 0.088 and 0.110 g/l-1 and on-line of 0.130 and 0.180 g/l-1 , respectively. The directed modification of quantitative models, by the inclusion of spiked process samples improved the SEP for lactone prediction where bioprocess development meant existing NIR models were not relevant. The ...
ADH-A from Rhodococcus ruber DSM 44541 catalyzes the oxidation of (S)-1-phenylethanol 3000-fold more efficiently as compared with the 2-hydroxylated derivative (R)-phenylethane-1,2-diol. The enzyme is also highly selective for sec-alcohols with comparably low activities with the corresponding primary alcohols. When challenged with a substrate containing two secondary alcohols, such as 1-phenylpropane-(1R,2S)-diol, ADH-A favors the oxidation of the benzylic carbon of this alcohol. The catalytic efficiency, however, is modest in comparison to the activity with (S)-1-phenylethanol. To investigate the structural requirements for improved oxidation of vicinal diols, we conducted iterative saturation mutagenesis combined with activity screening. A first-generation variant, B1 (Y54G, L119Y) displays a 2-fold higher k(cat) value with 1-phenylpropane-(1R,25)-diol and a shift in the cooperative behavior in alcohol binding, from negative in the wild type, to positive in B1, suggesting a shift from a less ...
Au(I) catalysis has recently emerged as a powerful tool for the realization of a broad range of organic transformations. Despite this rapid development, attaining selectivity and maintaining catalyst stability remain significant challenges. Rational ligand design, such as the employment of NHC or TA ligands, has been used to confront these issues. This thesis focuses on the use of Au(I) catalysts bearing these ligands for the selective hydroalkynylation of enol ethers. By employing a TA-Au stabilized catalyst, [(OAr)3PAu(TA-H)]OTf, the intermolecular hydroalkynylation of enol ethers, a substrate that is well-known to promote decomposition of the gold cation, was efficiently achieved. As an expansion of this reaction, the NHC-Au catalyst, IPrAuNTf2, was utilized in a multicomponent system to promote the tandem hydroalkynylation of enol ethers formed in-situ via the cycloisomerization of alkynols. Further exploration of this tandem reaction revealed that IPrAuNTf2 catalyzes a cascade ring-expansion of the
SWISS-MODEL Repository entry for A1B3F9 (MURA_PARDP), UDP-N-acetylglucosamine 1-carboxyvinyltransferase. Paracoccus denitrificans (strain Pd 1222)
gLiving Ring Opening Metathesis Polymerizations of Cyclic Olefins, h Novak, B. M., Grubbs, R. H. in Encyclopedia of Polymer Science and Engineering, 2nd Edition, Mark, H. F.; Bikales, N. M.; Overberger, C. G.; Menges, G.; Kroschwitz, J. I., Eds., John Wiley and Sons, Inc., New York, 1990, p. 420 ...
The first project involved the investigation of dibenz[c,e]azepinium salt 113 as a catalyst for the aldol reaction. The catalyst was synthesised in 4 steps from commercially available 1R,2R-diaminocyclohexane in 74% overall yield. It was found to be an efficient catalyst in the aldol reaction of cyclic ketones with a range of aromatic aldehydes, giving high yields, diastereo- and enantioselectivities. This catalyst was also found to be effective when acyclic ketones were used, in which case the major diastereoisomer produced was no longer an anti-aldol but a the syn-aldol. A catalytic cycle for these reactions is proposed, with the stereochemical outcome of these reactions being further investigated by computational calculations ...
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