| 초록 |
Zeolitic imidazole framework ZIF-7 (Zn(benzimidazole)2) was known to have gate-opening phenomenon according to the temperature and pressure in the presence of guest molecules, which make it be utilized in H2, CO2, and paraffine separation technology. ZIF-7 can be used as a catalyst also due to its Lewis acid site on Zn and Lewis basic site on benzimidazole. In this study, for the first time, we found ZIF-7 is a very promising material as a catalyst at the methoxycarbonylation of aniline with dimethyl carbonate (DMC) to produce methyl phenyl carbamate (MPC), an isocyanate precursor. Fresh ZIF-7 showed high aniline conversion over 95% at 190 oC for 2 h, the yield MPC was 60 - 70% due to the formation of methylated side products, such as N-methyl aniline and N,N’-dimethylaniline. However, interestingly, when the ZIF-7 was reused, the yield of MPC gradually increased and reached over 94.7% by the catalyst’s 6th run. |
