Monomolecular acid hydrolysis

Monomolecular acid hydrolysis and esterification of the alkyl-oxygen bond cleavage (mechanism. 4al1)- ... 

With the realization that the cycloamyloses form stable monomolecular inclusion complexes in solution came the idea that the inclusion process might affect the reactivity of an organic substrate. This idea was initially pursued by Cramer and Dietsche (1959b) who discovered that the rates of hydrolysis of several mandelic acid esters are enhanced by the cycloamyloses. More recently, the inclusion process has been shown to exert both accelerating and decelerating effects on the rates of a variety of organic reactions. The remainder of this article will be devoted to a discussion of these reactions in an attempt to review, compare, and unify the many intriguing facets of cycloamylose catalysis. 

The importance of time, temperature and acid concentration in the hydrolysis of cellulose with dilute acid was recognized by early investigators and applied in the investigations of Simonsen in 1898. Further study was made by Kressman and reported in U. S. Department of Agriculture Bulletin No. 983. Reviews of the quantitative aspects have been made by Doree. Liiers pointed out that the conversion of cellulose dextrin to D-glucose by dilute sulfuric acid was a monomolecular reaction. The constants of the hydrolysis of wood cellulose have been determined by Saeman. The reaction rate (A ) was found to be expressed by the following equation ... 

The reaction kinetics studied using UV spectroscopy is formally identical to that of acid-catalyzed hydrolysis of l-alkoxybut-l-en-3-ynes (a first-order reaction with respect to the substrate and acid) (75IZV1975 78IZV153). At a constant acid concentration the reaction proceeds as a pseudo-monomolecular process. 

Edwards [25] investigated the hydrolysis of aspirin in aqueous solution at 17A° and demonstrated that the aspirin is hydrolyzed by general acid-base catalysis and water molecules for ionic and nonionic aspirin, comprising six simultaneous reactions involving H O, O H, and H2O for ionic and nonionic aspirin. The intrinsic hydrolysis rate constant in the heated mixture was comparable with the hydrolysis rate constants of the two-element reactions of nonionic aspirin and H2O or ionic aspirin and H2O in aqueous solution. As aspirin molecules would be adsorbed onto the pore surface of PCC in the molecular state, as a possible mechanism of aspirin hydrolysis in the mixture with PCC it was suggested that the aspirin is dispersed monomolecularly in the heated mixture and reacts with water molecules rather than by acid-base catalysis. 

When the concentration of the aqueous solution was 1% or lower, the production of methyl caffeate increased. However, the production of methyl caffeate was decreased in aqueous solutions greater than 2%. The production of caffeic acid was increased with addition of the buffer, indicating that the enzyme probably catalyzed hydrolysis of 5-caffeoylquinic acid to produce caffeic add rather than alcoholysis to produce methyl caffeate. Thus, the result indicated that the addition of 1% aqueous solution was suitable for the production of methyl caffeate. It was suggested that ILs are able to maintain active strudures of the enzymes with a monomolecular layer of water (Feher et al., 2007). Thus, chlorogenate hydrolase would maintain the active structure with the layer of the buffer in [bmim][NTf2]. 

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