苯乙烯臭氧化一步法合成苯甲醛的研究

Study on One-step Synthesis of Benzaldehyde from Styrene

摘要:

两性离子是臭氧化反应过程的活性中间体，本实验采用水或有机胺捕获苯乙烯臭氧化生成的两性离子，不经臭氧化物中间体及传统的还原分解反应一步法合成苯甲醛。考察了溶剂种类、溶剂用量、反应温度、臭氧流量和添加剂种类等因素对反应的影响。实验结果表明，水捕获两性离子的活性大于有机胺，不同有机胺的反应活性不同：三乙胺>三正丁胺>三正辛胺，叔胺>仲胺。较佳的反应条件(以0.05 mol苯乙烯计)为：溶剂丙酮25.0 mL，反应温度0~5℃，臭氧流量200 mL•min-1，n(水)：n(苯乙烯)=3:1。在该条件下，重复实验三次，所得苯甲醛的平均收率为96.5%。

Abstract:

Carbonyl oxides(zwitterion) are the most reactive intermediates in ozonolysis reaction. This paper describes the trapping carbonyl oxides by amines or H2O. The direct ozonolytic conversion of styrene to benzaldehyde without the intermediacy of 1,2,4-trioxolanes(ozonides) and traditional reduction decomposition. The effect of the type of solvent, amount of solvent, reaction temperature, the flow of ozone and the kind of additive were investigated. The results show that H2O gives better reactivity than amines, different amines reactivity decreased in the order:Et3N>Bu3N>(C8H7)3N, tertiary amine>secondary amine. The appropriate reaction conditions are as follows (based on 0.05 mol styrene): 25.0 mL acetone as solvent, reaction temperature 0～5℃, the flow of ozone 200 mL•min-1, n(H2O):n(styrene)=3:1. Under above conditions, the average yield of benzaldehyde is about 96.5%.