US EPA

7578730 

Journal Article 

Synthesis of 4,4'-MDC in the presence of [emim]BF4 ionic liquid modified with H+ 

Hu, LY; Geng, YL; Zhao, XQ; Wang, YJ 

2007 

21 

3 

467-470 

Chinese 

The synthesis of methylene diphenyl dimethylcarbamate(4,4'-MDC) from methyl N-phenyl carbamate (MPC) and formaldehyde was investigated in the presence of [emim]BF4 ionic liquid modified with H+ as both catalyst and reaction solvent. The influence of reaction temperature, molar ratio of MPC to HCHO, the amount of ionic liquid used and reaction time on 4,4'-MDC synthesis reaction was studied. Under the suitable reaction conditions of 70°C, n(MPC)/n(HCHO)=4/1, wt(ILs)/wt(MPC)=4/1 and reaction time of 1.5 h, the yield and selectivity of 4,4'-MDC are 71.74% and 71.91%, respectively. The used ionic liquid modified with H+ was treated by ultrasonic extraction with CHCl3 and was reused in the condensation reaction, and no significant loss in catalytic activity was observed. 

[emim]BF4 ionic liquid; Formaldehyde; Methyl N-phenyl carbamate; Methylene diphenyl dimethylcarbamate; Catalyst activity; Catalysts; Condensation; Condensation reactions; Extraction; Formaldehyde; Ionic liquids; Organic acids; Synthesis (chemical); Ultrasonics; [emim]BF4 ionic liquid; Methyl N-phenyl carbamate; Methylene diphenyl dimethylcarbamate; Ultrasonic extraction; Esters