异丙苯液相催化氧化

Liquid Phase Catalytic Oxidation of Cumene

在500 mL.钛制间歇釜中,以异丙苯为原料,醋酸为溶剂,醋酸钴、醋酸锰和溴化氢为催化剂,空气为氧化剂,考察催化剂浓度和反应温度对产物组成和反应速率的影响,并分析异丙基氧化产物结构。结果表明,比较适宜的反应条件为180℃,催化剂Co和Mn与反应物异丙苯物质的量之比为0.05,该条件下,异丙苯可以完全转化,苯甲酸的收率为95%。异丙苯氧化产物主要为α-甲基苯乙烯、苯乙酮、α-甲基苯乙烯的聚过氧化物以及苯甲酸;整个氧化过程中,α-甲基苯乙烯与氧气作用形成聚过氧化物的反应是影响苯甲酸收率的关键因素;提高反应温度和增加催化剂浓度都能改变α-甲基苯乙烯的聚过氧化物的稳定性,使其开裂并最终转化为苯甲酸。

The effects of catalyst dosage and reaction temperature on the composition of products and reaction rate of liquid phase catalytic oxidation of cumene with oxygen using acetic acid as solvent in the presence of catalysts consisting of cobalt acetate, manganese acetate and bromine compound were investigated in a 500 mL titanium reactor and the structures of the products were analyzed. The results showed that cumene were all conversed and the yield of benzoic acid reached 95% under the appropriate reaction conditions of 180 ℃ and the molar ratio of Co and Mn to cumene 0.05. α-methylstyrene（MS）, acetophenone（AP）, α-methylstyrene polyperoxide and benzoic acid （BA） were main products of oxidation of CU. The most important side reaction was copolymerization of α-methylstyrene with oxygen, which had a significant influence on oxidation of cumene. The yield of benzoic acid could be improved by increasing operational temperature and catalyst dosage which could accelerate cleavage of polyperoxide to form benzoic acid.