H-Ion Catalysis by Clays

Abstract

AbstractAcid clays prepared by electrodialysis or by treatement with dilute (< about 0.1N) mineral acid solutions were largely Al-saturated, and had little catalytic effect on ester hydrolysis and sucrose inversion. On the other hand, clays exhaustively treated with cold 1N HCl were largely H-saturated, and served as effective H-ion catalysts. When various quantities of clay were used as catalysts, reaction rates were proportional to the concentration of H-ions in the system.H-montmorillonites prepared from Plymouth, Utah bentonite and from Volclay bentonite were from 50 to 200 percent more effective catalysts for ethyl acetate hydrolysis than was HCl. For sucrose inversion, <2 μ H-clays had a somewhat greater catalytic effect than did HCl, while clay aggregates were much less effective catalysts. For ester hydrolysis, the degree of dispersion of the clay made little difference in its catalytic activity.