摘要
对氨基甲酸酯热分解法制备对氯苯基异氰酸酯(4CPI)的工艺进行了研究。以对氯苯胺和碳酸二甲酯为原料,合成了热分解前体对氯苯基氨基甲酸甲酯(M4CPC);通过核磁共振氢谱、傅里叶变换红外光谱和热重分析对M4CPC的结构和性能进行了表征,确定了适宜的M4CPC热分解温度为150～200℃。常压下对M4CPC热分解溶剂的考察结果表明,高介电常数的有机溶剂对M4CPC的分解比较有利。M4CPC热分解制备4CPI的主要副产物为N,N′-双(4-氯苯基)脲。以低毒的N,N′-二甲基乙酰胺为溶剂,在M4CPC的摩尔分数为10%、催化剂用量为m(Bi2O3)∶m(M4CPC)=0.05、反应温度162～164℃、反应时间1h的优化条件下,M4CPC的转化率为90.4%,4CPI的选择性为66.0%。
The process for synthesizing of 4-chlorophenyl isocyanate （4CPI） by thermal decomposition of carbamate and using Bi203 catalyst was studied. The starting reactant methyl N-（4-chlorophenyl ） carbamate （M4CPC） was firstly synthesized from p-chloroaniline and dimethyl carbonate. The structure and properties of M4CPC were investigated by means of ^1H NMR, FTIR and TG analysis. From TG results, the appropriate temperatures for thermal decomposition of M4CPC were decided in the range of 150 -200 ℃. Under normal pressure, solvents with higher dielectric constants were suitable for the liquid thermal and catalytic decomposition of M4CPC. With low toxic N, N＇- dimethylacetamide as solvent, the main byproduct of the thermal decomposition of M4CPC to 4CPI was N, N＇-bis （4-chlorophenyl） urea. Under optimal reaction conditions： mole fraction of M4CPC 10%, mass ratio of catalyst Bi2O3 to M4CPC 0.05, reaction temperature 162 - 164 ℃ and reaction time 1 h, conversion of M4CPC is 90.4%, selectivity to 4CPI is 66.0%.
出处
《石油化工》
CAS
CSCD
北大核心
2009年第1期52-57,共6页
Petrochemical Technology
基金
“十一五”国家科技支撑计划重大项目(2006BAC02A08)
关键词
对氯苯基异氰酸酯
氨基甲酸酯
对氯苯胺
碳酸二甲酯
热分解
4-chlorophenyl isocyanate
carbamate
p-chloroaniline
dimethyl carbonate
thermal decomposition
