Specificity of reactions

Heterogeneous photochemical reactions fall in the general category of photochemistry—often specific adsorbate excited states are involved (see, e.g.. Ref. 318.) Photodissociation processes may lead to reactive radical or other species electronic excited states may be produced that have their own chemistry so that there is specificity of reaction. The term photocatalysis has been used but can be stigmatized as an oxymoron light cannot be a catalyst—it is not recovered unchanged. 

The site specificity of reaction can also be a state-dependent site specificity, that is, molecules incident in different quantum states react more readily at different sites. This has recently been demonstrated by Kroes and co-workers for the Fl2/Cu(100) system [66]. Additionally, we can find reactivity dominated by certain sites, while inelastic collisions leading to changes in the rotational or vibrational states of the scattering molecules occur primarily at other sites. This spatial separation of the active site according to the change of state occurring (dissociation, vibrational excitation etc) is a very surface specific phenomenon. 

Organic solvents may improve substrate solubility, specificity of reaction and equilibrium reaction. The last two benefits are considered further in Section 2.6.2. 

Costs of downstream processing for purely chemical synthesis would be increased by 1) low specificity of reactions (giving rise to chemical contaminants closely related to the desired product) and 2) the toxic/corrosive nature of the chemicals. 

The specification of reactions 4 and 5 for the formation of N2O and N2 is based on the TPD studies reported by Castner et al. (19), Campbell and White (20), Baird et al. (21) and Myers and Bell (8). The work of Myers and Bell has shown specifically that the formation of N2O does not occur via a Rideal-Eley process. 

Commercial usage of PTC techniques has increased markedly during the last five years not only in the number of applications (currently estimated to be fifty to seventy-five different uses(22)), but also in the volume of catalysts consumed (estimated to be about one million pounds per year(22)) and in the volume of products manufactured (estimated to be fifty to one hundred million pounds per year(22)) in the United States alone. Many indicators point to additional extensive commercial applications of the PTC technique all around the world, and these indicators suggest that future chemical manufacturing processes will more an more incorporate PTC because of its advantages of simplicity, reduced consumption of organic solvents and raw materials, mild reaction conditions, specificity of reactions catalyzed, and enhanced control over both reaction conditions, reaction rates, and yields. For some currently produced pol3rmers PTC provides the only reasonable and practical commercial method of manufacture(22). 

Specificity of reaction, including a. substrate specificity aspartame... 

This difference in activation energies is due to the specifity of reactions in solid phase, where the mobility of the reacting particles is greatly reduced. 

The products were phenylglyoxal (XXXVTI) in 61% yield and the methoxyhydro-peroxide (XXXV) (melting point 60-1°) in 74% yield. It was felt that the actual yields were much better. The materials were difficult to isolate. The methoxyhydro-peroxide (XXXV) had to originate from zwitterion XXXVI which was Trapped through its reaction with methanol. This specificity of reaction can be explained, as in the other case, by the terminal oxygen attack of ozone and inductive effects in 1,2-... 

GIO. Goodman, M., and Ramsey, D. S., Specificity of reaction of chicken antiserum in high NaCl concentrations. Federation Proc. 16, 416 (1957). 

It is meaningless to talk more specifically about the effect of the drug. Set and setting, expectation, and atmosphere account for all specificity of reaction. There is no drug reaction but always setting-plus-drug... 

Set and setting, expectation, and atmosphere account for all specificity of reaction. 

The same workers have shown that a wide variety of acidic substrates form thallous salts by treatment with thallous ethoxide, and that these salts offer unique advantages either in yields, specificity of reactions, or convenience or simplicity in handling over alkali or other heavy-metal salts.4 Thallous salts of phenols, for example, are readily prepared in quantitative yield by the addition of thallous ethoxide to a solution of the phenol in benzene or ethanol. These salts are crystalline, sharp-melting, colorless... 

An epitope is the same as an antigenic site, but in which a greater specificity of reaction has been defined, e.g., using tests involving mAbs in which a single population of antibodies identifies a single chemical structure on an antigen. 

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