Acid activation as a method to control the catalytic properties of montmorillonite in the synthesis of solketal from glycerol and acetone

The effect of acid activation using 0.125–0.5 mol/l Н2SO4, HCl and HNO3 on the physicochemical and catalytic properties of natural clay (95 % montmorillonite, Mukhartalinsk deposit) was investigated. The rate and selectivity of the solketal (2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane) synthesis from glycerol and acetone were shown to depend on the concentration and type of the acid. The reaction rate and the yield of solketal increase with increasing concentration of the acid, which is consistent with the growth in the amount of Broensted sites. As the surface acidity increases, the efficiency of the system increases in the series MM/HCl > MM/HNO3 > MM/H2SO4.