冠醚催化氧化法合成对硝基苯甲酸

研究了冠醚作为相转移催化剂催化KMnO4氧化对硝基甲苯合成对硝基苯甲酸的反应,对影响反应的各种因素进行了分析讨论,如相转移催化剂用量、反应温度、反应时间、KMnO4用量等,优化了工艺条件.得出较优工艺条件为：n（KMnO4）∶n（对硝基甲苯）=3∶1,冠醚用量为反应底物的4％（摩尔分数）,反应温度为25℃,反应时间为6h,产物收率达74.8％.实验表明,冠醚对于KMnO4氧化对硝基甲苯合成对硝基苯甲酸的反应是一种优良的相转移催化剂.

Synthesis of P-nitrobenzoic acid by oxidation in presence of phase transfer catalyst crown ether

The catalytic synthesis of p-nitrobenzoic acid （PNBA） by oxidation of p-nitrotoluene with potassium permanganate （KMnO4） in the presence of phase transfer catalyst （PTC, crown ether） are reported. The factors on the yield were discussed, such as amount of catalyst, reaction temperature and time, amount of potassium permanganate etc. The optimal reaction conditions for preparing p-nitrobenzoic acid were stated as follows： molar ratio of KMnO4 to PNT was 3 ：1, molar amount of crown ether was 4%, reaction temperature is 25 ＊C, reaction time was 6 h, and the yield of PNBA was 76%. The experiment results show that crown ether is a good PTC for the synthesis.