磷钨酸催化低沸点芳烃液相硝化反应

研究了磷钨酸对苯、甲苯和氯苯液相硝化反应的催化活性,考察了反应温度、反应时间、硝酸与芳烃摩尔比对芳烃转化率和产物选择性的影响。实验结果表明,磷钨酸对低沸点芳烃液相硝化反应具有显著的催化活性,在优化的条件下,苯、甲苯和氯苯的转化率分别为98.0%,99.5%,100.0%。苯硝化反应产物中无多硝基苯生成,硝基苯的选择性高;甲苯硝化反应产物中,对硝基甲苯和邻硝基甲苯的摩尔比达到1.08,较经典的方法明显提高;氯苯硝化反应采用发烟硝酸作硝化剂,氯苯转化率高于以浓硫酸为底酸、硝酸为硝化剂的方法。

Liquid-Phase Nitration of Low Boiling-Point Aromatic Hydrocarbons Catalyzed by Phosphotungstic Acid

Catalytic activities of phosphotungstic acid for liquid-phase nitrations of benzene,toluene and chlorobenzene were studied.Effects of reaction temperature,reaction time and mole ratio of nitric acid to aromatic hydrocarbons on performance of the catalyst were investigated.Under optimized reaction conditions,conversions of benzene,toluene and chlorobenzene can reach 98.0%,99.5% and 100.0%,respectively.Selectivity to nitrobenzene is very high in nitration of benzene.Especially,mole ratio of p-nitrotoluene to o-nitrotoluene in nitration of toluene could reach 1.08,much higher than that by conventional nitration method.Conversion of chlorobenzene in nitration using fuming nitric acid as nitrating agent was higher than that obtained alternatively by nitric acid and concentrated sulfuric acid.