摘要
传统的浓硝硫混酸硝化甲苯不仅会产生大量废物,而且区域选择性不高。针对此问题,通过浸渍法制备了MoO3/SiO2负载型固体酸催化剂,研究了在其催化下新型硝化剂五氧化二氮对甲苯的硝化反应。实验考察了反应温度、反应时间、催化剂用量及重复使用等因素对反应结果的影响。研究表明,当反应温度为30℃,反应时间为60min,催化剂用量为3g时,甲苯硝化产物中异构体的邻对比例达1.26,明显低于浓硝硫混酸的比例1.67。该催化剂可循环使用5次,还保持较高的活性。
.Huge amounts of wastes were produced along with low selectivity in toluene nitration by the traditional concentrated mineral acids as the catalyst.In order to solve the problem,MoO3/SiO2 catalyst was prepared by impregnation method,and the nitration of toluene by new nitrating agent N2O5 has been investigated with solid acid catalysts.The effects of reaction temperature,reaction time,amount of catalyst and recovered catalyst on the nitration were investigated,which showed that when nitration reaction temperature was controlled at 30℃,the reaction time was 60 min,nitration of toluene with 3g catalyst,a high selectivity with ortho-para isomer ratio up to 1.26 in product distribution of toluene nitration,greatly below ortho-para isomer ratio of 1.67 with sulfonitric mixed acid as catalyst.The catalyst could be reused directly for 5 times with high activity.
关键词
五氧化二氮
甲苯
硝化
固体酸
dinitrogen pentoxide
toluene
nitration
solid acid
