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采用对硝基甲苯为原料,经卤代、超声辐射相转移催化水解及超声辐射Pt/C催化转移加氢等3步反应,以67.4%的总收率合成了标题化合物。结果表明:N-溴代丁二酰亚胺为较好的卤代试剂,生成对硝基苄溴的收率为75.4%;以四丁基溴化铵为相转移催化剂,在碱性条件下于70℃时超声辐射0.5 h,对硝基苯甲醇的收率为94.8%;考察了超声辐射Pd/C催化甲酸铵还原对硝基苯甲醇的影响因素,优化了反应工艺:在n(对硝基苯甲醇)∶n(甲酸铵)为1∶4,m(对硝基苯甲醇)∶m(Pd/C)为100∶5,超声功率为150 W,超声温度为50℃,反应时间为15 min的条件下,对氨基苯甲醇的收率为94.3%,Pd/C容易分离回收,可重复使用6次以上。用IR、1HNRM、MS谱及元素分析等测试技术表征了产物的结构。
Using p-nitrotoluene as raw material, the title compounds were synthesized by halogenated reaction, ultrasonic radiation phase-transfer catalytic hydrolysis and Pt / C catalytic transfer hydrogenation by ultrasonic irradiation. The title compound was synthesized in 67.4% overall yield. The results showed that N-bromosuccinimide was the best halogen reagent and the yield of p-nitrobenzyl bromide was 75.4%. Using tetrabutylammonium bromide as phase-transfer catalyst, under the alkaline conditions The yield of p-nitrobenzyl alcohol was 94.8% after ultrasonic irradiation at 70 ℃ for 0.5 h. The influence factors of p-nitrobenzyl alcohol reduction by Pd / C catalyzed by ammonium formate were investigated, and the reaction process was optimized. (P-nitrobenzyl alcohol): m (Pd / C) was 100: 5, the ultrasonic power was 150 W, the ultrasonic temperature was 50 ℃, the reaction time For 15 min, the yield of p-aminobenzyl alcohol was 94.3%. Pd / C was easily separated and recovered, which could be reused more than 6 times. The structure of the product was characterized by IR, 1HNRM, MS and elemental analysis.