Kinetics combination reactions

Commercially useful materials require that the rate of the combined reaction is rapid. If the darkening takes place too slowly, or if the subsequent fading of the color is too slow, the materials will not be useful. The presence of the copper halide is essential in ensuring that the kinetics of the reaction are appropriate and that the process is reversible. 

Kinetically controlled epoxy curing reactions, 10 423 Kinetic barriers, 11 529 Kinetic friction, 15 224 Kinetic incompatibility, in acrylonitrile copolymerization, 11 203 Kinetic measurements, 14 607-629. See also Very fast kinetics combined methods for unstable reagents, 14 621... 

Pellissier, H., Recent developments in dynamic kinetic resolution. Tetrahedron, 2008, 64, 1563-1601 Turner, N.J., Enzyme catalysed deracemisation and dynamic kinetic resolution reactions. Curr. Opin. Chem. Biol., 2004, 8, 114-119 Gmber, C.C., Lavandera, I., Faber, K. and Kroutil, W., From a racemate to a single enantiomer deracemisation by stereoinversion. Adv. Synth. Catal., 2006, 348, 1789-1805 Pellissier, H., Dynamic kinetic resolution. Tetrahedron, 2003, 59, 8291-8327 Pmnies, O. and Backvall, J.-E., Combination of enzymes and metal catalysts. A powerful approach in asymmetric catalysis. Chem. Rev., 2003, 103, 3247-3261. 

The reversibility of hydrogen transfer reactions has been exploited for the racemi-zation of alcohols and amines. By coupling the racemization process with an enantioselective enzyme-catalyzed acylation reaction, it has been possible to achieve dynamic kinetic resolution reactions. The combination of lipases or... 

The mechanism and kinetics of RAFT-SIP were studied by Fukuda et al. [326]. Besides the expected linear increase of the molecular weight of the surface grafted polymer with the monomer conversion, they observed the appearance of a prominent low molar mass fraction which was attributed to a combination reaction of the propagating active chains. 

The kinetic template effect is observed in reactions in which the metal ion acts by coordinating the reactants. This effect has also been described as a coordination template effect. A more direct description of a kinetic template reaction is one which involves Combination of two Ligands Attached to the same. Metal ion. Such a description leads to the useful acronym CLAM reaction , which graphically portrays the key reaction step. The process can be generalized and compared with the non-template reaction in Scheme 30. 

Jonsson M, Lind J, Reitberger T, Eriksen TE, Merenyi G (1993) Free radical combination reactions involving phenoxyl radicals. J Phys Chem 97 8229-8233 Kapoor SK, Gopinathan C (1992) Reactions of halogenated organic peroxyl radicals with various purine derivatives, tyrosine, and thymine a pulse radiolysis study. Int J Chem Kinet 24 1035-1042 Khaikin Gl, Neta P (1995) Formation and reactivity of vinylperoxyl radicals in aqueous solutions. J Phys Chem 99 4549-4553... 

Misiaszek R, Uvaydoc Y, Crean C, Geacintov NE, Shafirovich V (2005) Combination reactions of superoxide with 8-oxo-7,8-dihydroguanine radicals in DNA kinetics and end-products. J Biol Chem 280 6293-6300... 

Kinetic investigations - cis- and trans effects already discussed from a static point of view [190] are also reflected in kinetic measurements. Reaction (11) was studied for combinations of L and L = 1-Meim, Py, PBu3 and P(OBu)3 [218]. 

R. Misiaszek et al., Combination reactions of superoxide with 8-oxoG radicals in DNA kinetics and enol products. J. Biol. Chem. 280, 6293-6300 (2005)... 

Industrial chemical reactions are often more complex than the earlier types of reaction kinetics. Complex reactions can be a combination of consecutive and parallel reactions, sometimes with individual steps being reversible. An example is the chlorination of a mixture of benzene and toluene. An example of consecutive reactions is the chlorination of methane to methyl chloride and subsequent chlorination to yield carbon tetrachloride. A further example involves the chlorination of benzene to monochlorobenzene, and subsequent chlorination... 

In practice, a gray-box model is developed in steps. One early step is to decide which variables and interactions to include. This is often done by the sketching of an interaction-graph. It must then be decided if a variable should be a state or a dependent variable, and how the interactions should be formulated. In the case of metabolic reactions, the expression forms for the reactions have often been characterized in in-vitro experiments. If this has been done, there are also often in-vitro estimates of the kinetic parameters. For enzymatic networks, however, such in-vitro studies are much more rare, and it is hence typically less known which expression to choose for the reaction rates, and what a good estimate for the kinetic parameters is. In any case, the standard method of combining reaction rates, r,-, and an interaction graph into a set of differential equations is to use the stoichiometric coefficients, Sij... 

The aldehyde substrates may be used as racemic mixtures in many cases, as the aldolase catalyzed reactions can concomitantly accomplish kinetic resolution. For example, when DHAP was combined with d- and L-glyceraldehyde in the presence of FDP aldolase, the reaction proceeded 20 times faster with the D-enantiomer. Fuc 1-P aldolase and Rha 1-P aldolase show kinetic preferences (greater than 19/1) for the L-enantiomer of 2-hydroxy-aldehydes. Alternatively, these reactions may be allowed to equilibrate to the more thermodynamically favored products. This thermodynamic approach is particularly useful when the aldol products can cyclize to the pyranose form. Since the reaction is reversible under thermodynamic conditions, the product with the fewest 1,3-diaxial interactions will predominate. This was demonstrated in the formation of 5-deoxy-5-methyl-fructose-l-phosphate as a minor product (Scheme 5.5).20a 25 The major product, which is thermodynamically more stable, arises from the kinetically less reaction acceptor. 

Sylvester and Pitayagulsarn53,54 considered combined effects of axial dispersion, external diffusion (gas-liquid, liquid-solid), intraparticle diffusion, and the intrinsic kinetics (surface reaction) on the conversion for a first-order irreversible reaction in an isothermal, trickle-bed reactor. They used the procedure developed by Suzuki and Smith,51,52 where the zero, first, and second moments of the reactant concentration in the effluent from a reactor, in response to a pulse introduced, are taken. The equation for the zero moment can be related to the conversion X, in the form... 

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