关键词: SO^2-₄/TiO₂-WO₃, 固体超强酸, 催化, 丁酸丁酯, 缩醛, 缩酮

A novel solid superacid catalyst, SO^2-₄/TiO₂-WO₃, was prepared. Its catalytic activity for twelve important ketals andacetals was measured with esterification of n-butanoic acid with n-butyl alcohol as probing reaction. The preparation conditions of SO^2-₄/TiO₂-WO₃ have also been investigated, that is, the mass ratio of the H₂WO₄ used in the compound is 12.5%, the calcining temperature is 580 ℃, the calcining time is 3 h, and the soaked consistency of H₂SO₄ is 1.0 mol·L^-1. Experimental results showed that SO^2-₄/TiO₂-WO₃ is an excellent catalyst for the synthesis of twelve important ketals and acetals. The optimumreaction conditions are that the molar ratio of aldehyde/ketone to glycol is 1∶1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h. Under these conditions, the yield of 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 78.7%, 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane 83.0%, cyclohexanone ethylene ketal 85.9%, cyclohexanone 1,2-propanediol ketal 84.6%, butanone ethylene ketal 70.7%, butanone1,2-propanediol ketal 88.3%, 2-propyl-1,3-dioxolane 80.6%, 4-methyl-2-propyl-1,3-dioxolane 79.6%, 2-isopropyl-1,3-dioxolane 64.2%, 4-methyl-2-isopropyl-1,3-dioxolane 83.3%, 2-phenyl-1,3-dioxolane 75.3%, 4-methyl-2-phenyl-1,3-dioxolane 95.1%, respectively.

Key words: SO^2-₄/TiO₂-WO₃, solid superacid, catalysis, butyric butyl, acetal, ketal