Study Of Catalytic Synthesis Process For Methyl Phenyl Carbamate By Reaction Of Dimethyl Carbonate With Aniline

Methyl phenyl carbamate(MPC)- the intermediate of phenyl isocyanate is synthesized from aniline and Dimethyl Carbonate(DMC), which is considered as green chemistry substance, instead of phosgene. This synthesis route has some distinct advantage, such as moderate reaction conditions, inexpensive catalyst and the only by-product methanol which could be used in the synthesis of DMC by gas-phase oxidative carbonylation of methanol, and then high atom economic process can be acquired. So it is a prospective route for further development in clean production. Methyl Phenyl Carbamate(MPC) is an important intermediate for synthesis of isocyanate, the following research work concerning the catalysts and the process of MPC synthesis from DMC and aniline has been systematically done hi this thesis.A series of catalysts were estimated. Some kinds of catalysts, such as a -PbO, SnOBua, ZnO-Pb3O4 , and so on, which have good performance were selected out for the further research.It has been found that at 170 ℃, Aniline: DMC= 1: 5 (mol ratio ), after 4h of reaction, using 7.5 mol% of aniline ,the a -PbO catalyst exhibited high activity with 81% conversion of aniline; at 180℃, Aniline: DMC=1: 5 (mol ratio ), after 4h of reaction, using 5.5 mol% of aniline ,the SnBu2O catalyst exhibited high activity with 77.8% conversion of aniline; at 170℃, Aniline: DMC=1: 5 (mol ratio ), Zn: Pb=3:1(mol ratio), after 4h of reaction, the amount of catalyst used was 10 mol% of that of aniline, the composed catalysts by two metals ZnO-Pb3O4 catalyst exhibited high activity with 75.6% conversion of aniline. Reaction mechanism of metal oxides catalysts was proposed.A set of credible HPLC analysis conditions was set up, as the following: chromatographic column: Waters Symmetry Shield RP18(3.9rnmX150mm), mobile phase: V(CH3OH):V(H2O)=55:45, flow speed: 0.6ml/min, wavelength of ultraviolet detector: 260nm.Quantitative analysis of MPC was carried out by external standard method. The accuracy and precision of recovery test were done and the results were excellent.The study of synthesis of MPC from aniline and Methyl carbamate(MC) instead of DMC was carried out. It has found that at 180#, Aniline: MC=1: 2 (mol ratio ) , after 8h of reaction, the amount of catalyst used was that of 10 mol% of aniline, the SnX catalyst exhibited high activity with 99.4% conversion of aniline whendiethylene glycol dimethyl ether as dissolvent.