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  • reactants
  • In the formalism of transition-state theory the reaction coordinate is that coordinate in set of curvilinear coordinates obtained from the conventional ones for the reactants which, for each reaction step, leads smoothly from the configuration of the reactants through that of the transition state to the configuration of the products. (wikipedia.org)
  • The reaction coordinate is typically chosen to follow the path along the gradient (path of shallowest ascent/deepest descent) of potential energy from reactants to products. (wikipedia.org)
  • occur
  • Although severe cases of anaphylaxis can occur within seconds or minutes of exposure and can be fatal if untreated, many reactions are milder and can be ended with prompt medical therapy. (medicinenet.com)
  • As described by the third of Newton's laws of motion of classical mechanics , all forces occur in pairs such that if one object exerts a force on another object, then the second object exerts an equal and opposite reaction force on the first. (wikipedia.org)
  • If the ring opening of 3,4-dimethylcyclobutene were carried out under photochemical conditions the resulting electrocyclization would be occur via a disrotatory mode instead of a conrotatory mode as can be seen by the correlation diagram for the allowed excited state ring opening reaction. (wikipedia.org)
  • Electrocyclic reactions occur frequently in nature. (wikipedia.org)
  • Although often composed solely of intramolecular transformations, cascade reactions can also occur intermolecularly, in which case they also fall under the category of multicomponent reactions. (wikipedia.org)
  • Adverse
  • An adverse drug reaction ( ADR ) is an injury caused by taking a medication . (wikipedia.org)
  • Type A reactions, which constitute approximately 80% of adverse drug reactions, are usually a consequence of the drug's primary pharmacological effect (e.g. bleeding when using the anticoagulant warfarin ) or a low therapeutic index of the drug (e.g. nausea from digoxin ), and they are therefore predictable. (wikipedia.org)
  • Adverse drug reaction leading to hepatitis (drug-induced hepatitis) with granulomata . (wikipedia.org)
  • Could this be an adverse reaction to the Xanax or is it (probably) just coincidental? (drugs.com)
  • It could be adverse side effects, I had a similar reaction to Cymbalta (horrible stuff). (drugs.com)
  • epoxidation
  • Enzymatic epoxidation of phenylalanine-derived diketopiperazine forms the arene oxide, which undergoes a 6π disrotatory ring opening electrocyclization reaction to produce the uncyclized oxepine. (wikipedia.org)
  • kinetics
  • Some chain reactions have complex rate equations with fractional order or mixed order kinetics. (wikipedia.org)
  • The issue of solvent effects on reaction kinetics is also considered as an integral part. (wikipedia.org)
  • Hence, the interactions of flow phenomena, mass transfer , heat transfer , and reaction kinetics are of prime importance in order to relate reactor performance to feed composition and operating conditions. (wikipedia.org)
  • nuclear
  • In addition, theoretical studies of reaction dynamics involve calculating the potential energy surface for a reaction as a function of nuclear positions, and then calculating the trajectory of a point on this surface representing the state of the system. (wikipedia.org)
  • chloride
  • Illustrative use of the Appel reaction is the chlorination of geraniol to geranyl chloride. (wikipedia.org)
  • The acyl compounds required for this reaction can be obtained through a Friedel-Crafts acylation with aluminum chloride. (wikipedia.org)
  • The Nierenstein reaction is an organic reaction describing the conversion of an acid chloride into an haloketone with diazomethane. (wikipedia.org)
  • It is an insertion reaction in that the methylene group from the diazomethane is inserted into the carbon-chlorine bond of the acid chloride. (wikipedia.org)
  • The chloride then displaces the diazo group in an SN2 reaction, with N2 as the leaving group. (wikipedia.org)
  • acid
  • It should be appreciated that the Pinner reaction refers specifically to an acid catalyzed process, but that similar results can often be achieved using base catalysis. (wikipedia.org)
  • Psychotic Reaction" is a garage rock, acid rock, psychedelic rock and proto-punk song. (wikipedia.org)
  • Lewis acid activation is essential for complete reaction. (wikipedia.org)
  • pathway
  • In some cases, even limiting the amount of diazomethane gives a reaction process that stalls via the neutral diazoketone pathway, requiring the addition of HCl gas to rescue it. (wikipedia.org)
  • sequence
  • A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. (wikipedia.org)
  • The efficiency and utility of a cascade reaction can be measured in terms of the number of bonds formed in the overall sequence, the degree of increase in the structural complexity via the process, and its applicability to broader classes of substrates. (wikipedia.org)
  • atoms
  • Nernst suggested that the photon dissociates a Cl 2 molecule into two Cl atoms which each initiate a long chain of reaction steps forming HCl. (wikipedia.org)
  • coordinate
  • The theory is based on the assumption that the reaction can be described by a reaction coordinate, and that we can apply Boltzmann distribution at least in the reactant state. (wikipedia.org)
  • known
  • Spectroscopic observation of reaction dynamics on the shortest time scales is known as femtochemistry, since the typical times studied are of the order of 1 femtosecond = 10−15 s. (wikipedia.org)
  • chain
  • For other uses, see Chain reaction (disambiguation) . (wikipedia.org)
  • In a chain reaction, positive feedback leads to a self-amplifying chain of events . (wikipedia.org)
  • Chain reactions are one way that systems which are not in thermodynamic equilibrium can release energy or increase entropy in order to reach a state of higher entropy. (wikipedia.org)
  • If a reaction results in a small energy release making way for more energy releases in an expanding chain, then the system will typically collapse explosively until much or all of the stored energy has been released. (wikipedia.org)
  • Numerous chain reactions can be represented by a mathematical model based on Markov chains . (wikipedia.org)
  • Christiansen and Kramers also noted that if, in one link of the reaction chain, two or more unstable molecules are produced, the reaction chain would branch and grow. (wikipedia.org)
  • The main types of steps in chain reaction are of the following types. (wikipedia.org)
  • Propagation (may comprise several elementary steps in a cycle, where the active particle through reaction forms another active particle which continues the reaction chain by entering the next elementary step). (wikipedia.org)
  • The chain length is defined as the average number of times the propagation cycle is repeated, and equals the overall reaction rate divided by the initiation rate. (wikipedia.org)
  • catalyst
  • In effect the active particle serves as a catalyst for the overall reaction of the propagation cycle. (wikipedia.org)
  • Frequently the term relates specifically to catalytic reaction systems where either a homogeneous or heterogeneous catalyst is present in the reactor. (wikipedia.org)
  • This reaction does not take place in a single step but leads first to dihydropentacene that is dehydrogenated in a second step with copper as a catalyst. (wikipedia.org)