1、 液相催化加氢法制取芳胺 摘 要 芳胺产品广泛应用于化工、医药、染料、农药等领域。绝大多数的芳胺都 来自相应的硝基化合物。将硝基芳烃还原为芳胺是一类重要的还原反应,在精 细化工中间体的生产甲占有极重要的地位。将硝基芳烃还原为芳胺的方法较多, 有化学还原法如铁粉还原,电解还原法和催化氢化法等。当前应用较广的化学 还原法由于在生产过程中污染环境而逐渐被其他方法所取代。电解还原法由于 较高的生产成本还无法在生产实践中发挥作用。催化氢化法,尤其是液相催化 加氢法以其独特的还原过程,在提高产品品质的同时,大大缓解了对环境的污 染。在环境问题日益受到人们关注的今天,在化工生产中推广和利用这一方法, 无疑会
2、产生显著的经济和社会效益。 随着生产实践的不断发展,人们对催化加氢的研究亦日益深入。本文综述 了近年来液相催化加氢的研究成果。着重研究了液相催化加氢技术在医药特别 是麻醉药普鲁卡因和氨苯丁酯合成中的应用。在催化加氢制备普鲁卡因的过程 中,自制了 Raney 镍催化剂,探讨了 Pd/C 催化剂和 Raney 镍、催化加氢效果。 从降低生产成本的角度,优选了一定目数的镍铝合金制备的 Raney 镍做催化剂, 将催化加氢法引入普鲁卡因生产工艺。对反应中间产物硝基卡因催化加氢,探 讨了催化剂用量、温度、压力、转速、反应时间等因素对产率的影响,确定了 生产该产品的最佳工艺条件。催化加氢法制备普鲁卡因产率
3、达 85%,含量达 98.02%,产品后处理简单经济,克服铁粉还原工艺中三废严重,劳动强度大, 产率较低和产品品质较差的缺陷。 本文还考察了催化剂、温度、压力、转速、反应时间等因素对催化加氢制 备氨苯丁酯的影响,确立了催化加氢法生产氨苯丁酯的最佳工艺条件:温度 90,氢压 2.SMPa,催化剂用量为原料量的 15%。氨苯丁酯加氢转化率达 99%, 产率达 75.4%,含量达 95.6%。并对催化加氢制备对氨基苯甲酸作了初步探讨。 II 关键词:芳胺 硝基芳烃 液相催化加氢 催化剂 还原 Abstract Aromatic amines are widely used in dyestuffs,
4、pharmaceutical products, agricultural chemicals,surfactants. And most of the aromatic amines come from corresponding nitro compounds. Reducing the nitroarene to aromatic amines is an important reaction in the production of fine chemical. There are many methods of reducing nitro to amine, such as the
5、 Bechamp reduction employed iron, electrolysis reduction,catalytic hydrogenation and so on. Bechamp reduction brought out serious pollution to environment,and it should be replaced by other means someday. Electrolysis reduction cannot be brought into practice because of higher cost. Catalytic hydrog
6、enation, especially liquid catalytic hydrogenation, relieves pollution for environment greatly and promotes the production quality. With the increasing attention to environment problems, popularizing the catalytic hydrogenation technology in the industry production must bring prominent economic and social benefits. With the development of science,the study for catalytic hydrogenation has been pushed continuously. This paper summarizes the catalytic hydrogenation development recent years. This d