催化加氢合成3,5-二甲基-1,2-苯二胺的工艺优化

Process Optimization of Synthesizing 3,5-dimethylbenzene-1,2-diamine by Catalytic Hydrogenation

研究以1,5-二甲基-2,3-二硝基苯为底物,通过Pd/C催化氢化合成3,5-二甲基-1,2-苯二胺的工艺。考察不同溶剂、反应压力、催化剂用量、反应温度、反应时间及催化剂重复使用次数诸因素对产物3,5-二甲基-1,2-苯二胺收率的影响。最佳工艺为:底物0.015 mol,甲醇溶剂30 mL,10%Pd/C催化剂质量分数为5%,反应压力0.5MPa,反应温度60℃,反应时间5h,产物3,5-二甲基-1,2-苯二胺为白色晶体,平均收率大于94%。产品结构经红外、质谱及核磁数据表征确认。

In this paper, the process of synthesizing 3,5-dimethyl-l,2-diaminobenzene by using the methods of catalytic hydrogenation which use 1,5-dimethyl-2,3-dinitrobenzene as the substrate, and Pd/C as the catalyst is studied. The different factors which may influence the yield of the3,5-dimethyl-1,2-diaminobenzene, such as solvents, pressure,catalyst dosage, temperature, time and the number of the catalyst reused are discussed.The results show that the best performance occurs under the circumstance of 0.015 mol substrate , 30 mL methanol solvent, 5% dosage of catalyst ,0.5MPa of the pressure , 60℃ of the temperature ,5 hours of the reaction time; after filtering,vacuum distillation and recrystallization, we can get the product 1,5-dimethyl-2,3-diaminobenzene which is white crystal , and the yield is greater than 94%.The structure of the product is also confirmed by IR, MS and ^1H-NMR data.