Reaction simultaneously

Several species of bacteria under suitable conditions cause / -butyraldehyde to undergo the Canni22aro reaction (simultaneous oxidation and reduction to butyric acid and butanol, respectively) this reaction can also be cataly2ed by Raney nickel (7). The direct formation of butyl butyrate [109-21 -7] or isobutyl isobutyrate [97-85-8](Vish.ch.erik.o reaction) from the corresponding aldehyde takes place rapidly with aluminum ethylate or aluminum butyrate as catalyst (8). An essentially quantitative yield of butyl butyrate, CgH2 02, from butyraldehyde has been reported usiag a mthenium catalyst, RuH,[P(C,H,)3], (9). 

The only reaction series involving a reaction at a heteroatom which has been extensively studied is the basicity of substituted pyridines. The Hammett equation was first applied to this reaction simultaneously by Brown and co-workers and by Jaffe and Doak. A sampling... 

A histidine deprotonates the acetyl-CoA enol, which adds to the ketone carbonyl group of oxaloacetate in an aldol-like reaction. Simultaneously, an acid N-H proton of another histidine protonates the carbonyl oxygen, producing (S)-citryl CoA. 

Decay transients, photo electrodes and, 505 Degradation rate as a function of polarization time, 328 Degradation reactions simultaneous with electrode polymerization, 326 DeLevie on the density of broken bonds and the effect on the potential of zero charge, 75... 

Electrode potentials components of, 9 energy scales and, 7 photo currents as a function of, 473 Electrode polymerization of conducting polymers, 314 and degradation, 325 degradation reactions simultaneous with, 326... 

Note that all the ions involved have already been produced by previous reactions and that apart from those of Reactions 30 and 33 the heats of reaction are small. Thus, with these reactions and similar ones, there is no reason why equilibria should not be maintained. Again, the need to treat a large number of reactions simultaneously to explain the results is stressed. A computer study of such a reaction scheme is now under way at AeroChem. 

Fig. 7.2 Differences in reaction progress of light and heavy isotope as a function of the fraction of reaction (simultaneous non-competitive measurement of isotope effects)...

Finally, it has to be emphasized that both the hydrodynamic parameters and the concentrations of the species involved in the extraction reaction simultaneously determine whether the extraction regime is of kinetic, diffusional, or mixed diffusional-kinetic type. It, therefore, is not surprising that different investigators, who studied the same chemical solvent extraction system in different hydrodynamic and concentration conditions, may have interpreted their results in terms of completely different extraction regimes. 

Methacycline Methacycline, 4-dimethylamino-l,4,4a,5,5a,6,ll,12a-octahydro-3,6,10, 12,12a-pentahydroxy-6-methylen-l,ll-dioxo-2-naphthacencarboxamide (32.3.6), is synthesized from oxytetracycline (32.3.2), which is reacted with a sulfur trioxide— pyridine complex, resulting in an oxidation reaction. Simultaneous sulfonation gives a naphthacen-snlfotetrahydrofuran derivative intermediate (32.3.5), which when reacted with hydrofluoric acid forms methacycline (32.3.6) [222-225]. 

A species may participate in a number of reactions simultaneously. In the simplest case, we may have... 

Instead of using an electrochemical and enzymatic reaction simultaneously for the regeneration, one can also use an enzymatic reaction only, as shown below. 

Perhaps, a more important reason for the little research in this particular area is the slow reaction rate associated with acid catalysis in general. However, the ability of solid acids to catalyze both esterification and transesterification reactions simultaneously and the possibility for employing catalysts that are reusable and green, meaning that they do not pose a great environmental threat, are attractive aspects that make the study of these materials imperative. 

A rel = 1.2 x 10 6) (Ingold, 1957). Neopentyl halides are known in fact to be extremely stable towards nucleophilic displacement. There are few examples in the gas phase that allow for a full comparison since alkyl halides with P-hydrogens may be prone to undergo elimination reactions simultaneously with displacement. For example, the reaction of F with C2H5C1 proceeds with a rate constant krel = 0.86, compared to that of CH3C1 (Jose, 1976), whereas (CH3)3CCH2C1 reacts with k[cl = 0.61 (Olmstead and Brauman,... 

Thus, nonequilibrium electrons and holes generated by light in a corroding semiconductor are consumed to accelerate the corresponding partial reactions. Simultaneous disappearance of these carriers in the course of photocorrosion is similar, from the formal point of view, to surface recombination. This gives every reason to speak about such processes as electrochemical recombination (Belyakov et ai, 1976). If the dark corrosion rate and equilibrium concentration of minority carriers are known, the rate of electrochemical recombination can be calculated. 

Note that in practice the abstract species A and B may themselves already be molecules or supermolecules formed from prior condensations, but simple probability arguments make condensation reactions simultaneously involving more than two species impossible under most sets of experimental conditions. The rate law associated with eq. 15.11 is... 

At each of the three points where glycolytic reactions are bypassed by alternative, gluconeogenic reactions, simultaneous operation of both pathways would consume ATP without accomplishing any chemical or biological work. For example, PFK-1 and FBPase-1 catalyze opposing reactions ... 

Intramolecular Diels-Alder reactions simultaneously form both rings. Precursors can be used which do not contain a heteroatom in either the 4tt or the 2tt component (e.g. Scheme 16). 

Parallel reactions are said to arise when a compound undergoes two or more reactions simultaneously. Enzymatic reactions often occur in parallel, when an activated intermediate may react with several competing acceptors ... 

WOLFFENSTEIN-BOTERS REACTION. Simultaneous oxidation and nitration of aromatic compounds to nitrophcnols with nitric acid or the higher oxides of nitrogen in the presence of a mercury salt as catalyst. Hydroxynitration of benzene yields picric acid. 

The notion reaction rate will be discussed more completely later (see Section VI), including the cases when the reaction simultaneously follows several pathways with the formation of different products. 

Predicting products can be challenging when you have to consider substitution and elimination reactions simultaneously. So far, we have seen substitution and elimination reactions separately. But now the truth comes out—substitution and elimination reactions are generally in competition with each other. To predict the products properly, you need to compare all factors for substitution and elimination reactions, and you then need to decide which of the four mechanisms predominates (S l or Sn2 or El or E2). 

In many experiments chemical equilibrium is assumed, however dynamic nonequilibrium processes in seawater may result in products different from those expected under equilibrium conditions. Equilibria can be complex and may involve several types of reactions simultaneously. Kinetics can therefore affect speciation of trace elements and should be taken into account. 

From these positions it becomes clear why the reaction of H202 dissociation to H20 and 02 cannot be induced directly by hydrogen peroxide this is because in this case, H202 dissociation would become the primary and the secondary reaction, simultaneously. 

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