负载型杂多酸催化苯硝化反应研究

STUDY ON NITRATION OF BENZENE TO NITROBENZENE OVER SUPPORTED HETEROPOLYACID CATALYST

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%。

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 nitrobenzene were evaluated. The HPAs were supported on SiO2, activated carbon, 5A molecular sieve, and γ-Al2O3 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 SiO2 is a better catalyst for nitration of benzene to nitrobenzene, when the volumetric ratio of benzene to HNO3 =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%.