Synthesis of Benzylaldehyde Glycol Acetal Catalyzed by SO_4~(2-)/γ-Al_2O_3

Benzaldehyde glycol acetal was synthesized by benzaldehyde and glycol with SO2-4/γ-Al2O3 as catalyst.The preparation conditions of the catalyst,such as concentration of sulfuric acid and calcination temperature were investigated.The effects of molar ratio of materials,the dosage of catalyst,the reaction time on the conversion of benzaldehyde were studied.The experiment results showed that the SO2-4/γ-Al2O3 was an excellent catalyst to synthesis of benzaldehyde glycol aceta1.The catalyst was prepared under the conditions of 2.5 mol·L-1 concentration of sulfuric acid and 650℃ of calcination temperature.The optimum reaction conditions were determined as follows: the molar ratio of benzaldehyde to glycol was 1∶2,the dosage of catalyst was 1.0 g,the amount of cyclohexane was 5 mL,the reaction time was 120 min and the reaction temperature was 100℃.Under above conditions,the conversion rate of benzaldehyde reached 96.51%.It was proved that SO2-4/γ-Al2O3 was regenerable.The catalytic activity of regenerated catalyst had relationship with the calcination temperature.