ZnO/Zn复配催化剂热分解4,4′-二苯甲烷二氨基甲酸甲酯制备4,4′-二苯甲烷二异氰酸酯的研究

Preparation of 4,4′-methylene di(phenylene isocyanate) (MDI) by catalytic decomposition of 4,4′-methylene di(phenylene carbamate) (MDC) with ZnO/Zn

考察了不同催化剂对4,4′-二苯甲烷二氨基甲酸甲酯(4,4′-MDC)催化分解制备4,4′-二苯甲烷二异氰酸酯(4,4′-MDI)反应的催化性能,结果表明ZnO/Zn复配催化剂对该反应具有较高催化活性,并具有低温的反应特点。ZnO/Zn复配催化剂的最佳质量比为1∶1。对ZnO/Zn复配催化剂催化反应的工艺条件进行了优化实验,结果表明在催化剂用量为溶剂质量的1.6%,原料用量为溶剂质量的2.5%,反应温度250℃,反应时间80min的最优条件下,MDC的转化率达到99.2%,其中4,4′-MDI单体的产率为67.3%。

The performance of various catalysts have been compared in the preparation of 4, 4＇-methylene di （phenylene isocyanate） （MDI） by catalytic decomposition of 4, 4＇-methylene di（phenylene carbamate） （MDC）. A ZnO/Zn catalyst showed a high performance at low temperature. The optimum mass ratio of ZnO to Zn was found to be 1：1. The optimum reaction conditions using this catalyst were 2.5 % MDC and 1.6 % catalyst （with respect to the weight of solvent） at a reaction temperature of 250℃with a reaction time of 80 min. Under these conditions the conversion of MDC was 99.2 % and the yield of MDI was 67.3 %.