改性4A型分子筛催化氨基甲酸甲酯和甲醇合成碳酸二甲酯.docVIP

 改性 4A 型分子筛催化氨基甲酸甲酯和甲醇 合成碳酸二甲酯# 韩冰1，赵文波1,2，朱培春1，刘骁1，肖振慧1，陈凤玲1，魏伟2** 5 10 15 20 （1. 昆明理工大学化学工程学院； 2. 中国科学院山西煤炭化学研究所煤转化国家重点实验室） 摘要：在碳酸二甲酯的众多合成反应中以尿素醇解法比较有工业化前景，该合成反应的决速 步为中间产物氨基甲酸甲酯和甲醇的反应。该文首先采用离子交换法制备出锌、铜、铅、镍 改性的 4A 分子筛催化剂，研究考察了离子交换条件对分子筛交换度的影响，结果发现初始 离子浓度对交换度影响较大，反应温度和反应时间对交换度影响较小。以此为理论依据制备 出一系列交换度为约 100%的改性分子筛并用于催化氨基甲酸甲酯和甲醇的反应，结果表明 锌，铅离子改性的 4A 分子筛尽管活性较差,但可以实现均相催化剂的非均相化。该文还进一 步考察了浸渍法制备的锌离子改性的分子筛对碳酸二甲酯催化合成的活性，结果发现其催化 效果明显，但锌离子在催化反应时会脱落，产生氯铵锌沉淀，不能实现均相催化剂的非均相 化。 关键词：碳酸二甲酯；氨基甲酸甲酯；离子交换；浸渍法；非均相催化 中图分类号：TQ226.3 Synthesis of dimethyl carbonate from methyl carbamate and methanol with modified 4A zeolite as catalyst HAN Bing1, ZHAO Wenbo1,2, ZHU Peichun1, LIU Xiao1, XIAO Zhenhui1, CHEN Fengling1, WEI Wei2 (1. Faculty of Chemical Engineering, Kunming University of Science and Technology; 25  Abstract: 2. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry) The synthesis method of dimethyl carbonate from urea and methanol has more industrialization prospect than many other synthesis methods. In this method, the rate-control step is the reaction of intermediate methyl carbamate with methanol. This work firstly applied ions exchange method to preparing a series of 4A zeolite catalysts modified by Zn、Cu、Pb、Ni. The 30 35 40 effect of reaction conditions on the ions exchange degree was investigated. The results showed that the initial ion concentration has greater impact on the degree of exchange, and the reaction time and temperature have less impact on the degree of exchange. According to this theoretical basis, a series of modified zeolite with ions exchange degree about 100% were prepared and used to catalyze the rate-control step reaction of dimethyl carbonate synthesis. Results showed that the activity of zinc and lead modified 4A zeolite was poor, but the homogenous catalyst was heterogenized. This work further examined the activity of impregnated zinc-modified zeolite in dimethyl carbonate synthesis. It is found that the activity of catalysis was