Correlation between the strength of the basic sites of catalysts and their activity in the decomposition of 2-methyl-3-butyn-2-ol as a test reaction

Abstract

A correlation was found between the strength of the basic sites of a series of solid oxides and their activity in the decomposition of 2-methyl-3-butyn-2-ol to give acetylene and acetone as a test reaction. Equations are given for the acidity function H0s and basicity function H–s for individual acidic and basic sites on the solid surface. The basicity of heterogeneous catalysts, similar to their acidity, is an important parameter, which permits us to evaluate their activity in proton transfer reactions. The H – acidity function is the accepted parameter for the strength of basic catalyst sites, while H 0 , the Hammett acidity function, is a parameter of the strength of acidic sites. These functions are determined using standard sets of indicators [1]. The question of how significantly the strength of catalyst sites affects the rate constant of a catalytic reaction is important. Such correlations are found for acidic catalysts, in particular, for the isomerization of o-xylene [1] and the dealkylation of cumene [2]. On the whole, the same tendency is noted for basic catalysts as for acidic catalysts, namely, catalyst activity rises with increasing strength of the basic sites as found, in particular, in the isomerization of 2,3-dimethyl-1-butene [3]. However, there are virtually no data in the literature on the correlation between H– and the rate constants of base-catalyzed reactions. In the present work, we present the relationship between the strength of basic sites of a series of oxides and their activity in the thermoprogrammed decomposition of 2-methyl-3-butyn-2-ol (MBOH), which is commonly used for the testing of both acidic and basic materials [4].