MDA催化加氢制备PACM的研究

Study on catalytic hydrogenation of MDA to prepare PACM

研究了由4,4-二氨基二苯基甲烷(MDA)在催化剂作用下加氢制备反-反式异构体含量在20%以下的4,4-二氨基二环己基甲烷(PACM)的工艺条件,考察了催化剂类型、反应温度、反应压力以及催化剂用量等对反应产物组成的影响,并初步考察了催化剂的套用性能。结果表明,采用Ru/Al_(2)O_(3)催化剂、较低的反应温度和较短的反应时间是获得产品高收率和低反-反式异构体选择性的关键。得出较佳的工艺条件为:使用物料总质量4%的Ru/Al_(2)O_(3)为催化剂、反应温度为130℃,压力为10MPa、反应时间为16h。催化剂连续套用10次后,产物中的反-反式异构体含量仍低于20%,PACM的收率高达98%。

The process conditions to prepare 4,4-diaminodicyclohexylmethane(PACM) with trans-trans isomer content below 20% used 4,4-diaminodiphenylmethane(MDA) under catalytic hydrogenation was studied.The effects of catalyst type,reaction temperature,reaction pressure and catalyst dosage on the composition of reaction products were investigated.And the reusability of catalyst was preliminarily investigated.The results showed that Ru/Al_(2)O_(3) catalyst,low reaction temperature and short reaction time are the main conditions to obtain high yield of products and low selectivity of trans-trans isomers.The optimum process conditions were as follows:the catalyst is Ru/Al_(2)O_(3) with 4% weight of raw material,the reaction temperature was about 130℃,the reaction pressure was 10 MPa,and the reaction time was 16 h.The recycle of the catalysts were also reviewed in this article,the content of trans-trans isomer in the products was still less than 20% yet after ten recycles,and the yield of PACM was up to 98%.