EFFICIENT HOMOGENEOUS ACID CATALYSIS OF HETEROPOLY ACID AND ITS CHARACTERIZATION THROUGH ETHER CLEAVAGE REACTIONS

A Keggin-type heteropoly acid has revealed high catalytic activities for the cleavage reactions of epoxides, tetrahydrofuran, dibutyl ether and butyl methyl ether with acetic acid, acetic anhydride and butyl acetate in the nonaqueous homogeneous liquid phase at 30-118 degree C. The catalytic activities of the heteropoly acid were much higher than those of conventional acid catalysts such as sulfuric acid, p-toluenesulfonic acid and boron trifluoride etherate, at the same catalyst concentrations or the same proton concentrations. On the basis of comparative measurements of electrical conductivity, acidity, and softness of anion for the solutions of acid catalysts, the efficient acid catalysis by heteropoly acid is suggested to be due to the specific properties of the heteropoly anion, which can be characterized by very weak basicity and great softness, together with the large size of polyhedral structure.