负载型杂多酸催化苯硝化反应研究

制备了3种 Keggin 型杂多酸,利用 IR 对其结构进行了表征,并对其催化苯液相硝化反应的性能进行了研究。采用等体积浸渍法制备了负载型磷钨杂多酸催化剂,考察了 SiO_2、活性炭、5A 分子筛、γ-Al_2O_3等载体对其催化性能的影响,以及催化剂的重复使用效果。结果表明,SiO_2负载的磷钨杂多酸催化剂具有较好的催化活性,在 V(苯)/V(硝酸)=1:3(摩尔比为1:3.5),反应温度75℃,反应时间3 h,负载型催化剂用量占总反应原料质量2%的条件下,硝基苯的收率为60.6%。

STUDY ON NITRATION OF BENZENE TO NITROBENZENE OVER SUPPORTED HETEROPOLYACID CATALYST

Three kinds of heteropoly-acids(HPAs)with Keggin structure were prepared,and their structures were verified by IR spectra,as well as their activities for nitration of benzene to nitroben- zene were evaluated.The HPAs were supported on SiO_2,activated carbon,5A molecular sieve,and γ-Al_2O_3 respectively by equal volume impregnation,and their influence on the catalytic performance and the reuse of the supported catalyst was studied.The results showed that the phosphotungstic acid supported on SiO_2 is a better catalyst for nitration of benzene to nitrobenzene,when the volumetric ra- tio of benzene to HNO_3=1:3(molar ratio 1:3.5),reaction temperature is 75℃,reaction time is 3 h,the amount of supported catalyst is 2%(w)of total reaction materials,the yield of nitrobenzene is 60.6%.