摘要
二苯甲烷二氨基甲酸甲酯(MDC)是非光气法合成二苯甲烷二异氰酸酯(MDI)的中间体。以硫酸为催化剂,盐酸盐为助剂,研究了苯氨基甲酸甲酯(MPC)与甲醛缩合制备MDC的反应。对助剂盐酸盐进行了筛选,发现氯化铜的效果较好,其MPC转化率达96%,4,4-′MDC产率可达76.7%。反应条件为:m(硫酸)∶m(MPC)=4∶1,n(MPC)∶n(HCHO)=1∶1,氯化铜用量为MPC物质的量的5.4%,100℃下反应3 h。将氯化铜分别与氯化镧和氯化亚铈以物质的量的比1∶1复合使用,发现单独使用氯化铜的效果好于复合盐酸盐的效果。分别使用甲醛溶液、三聚甲醛和多聚甲醛为亚甲基化剂,发现价廉易得的甲醛溶液效果最好。
Methyl methylene di (phenylene carbamate) (MDC) was the intermediate for synthesis of diphenylmethane diisocyanate via non-phosgene route. Condensation of methyl N-phenyl carbamate (MPC) with formaldehyde to methyl methylene di (phenylene carbamate) catalyzed by sulfuric acid with chloride as the promoter was investigated. CuCl2 was found to be an effective promoter. 4,4'- MDC yield of 76.7% and MPC conversion of 96% were obtained under the following condition: m(30% H2SO4): m (MPC) = 4: 1; n (inorganic salt) : n (MPC) = 5.4 : 100; n (MPC) : n (HCHO) = 1:1, reaction time 4 h, temperature 100℃. Effects of different promoters(CuCl2-La- Cl3, CuCl2-CeCl2, CuCl2) were compared, which showed that CuCl2 was superior to CuCl2-LaCIa and CuCl2-CeCl2. Formaldehyde, as methylene agent, was superior to trioxymetylene and paraformaldehyde.
出处
《工业催化》
CAS
2006年第8期44-47,共4页
Industrial Catalysis