| 초록 |
Zeolitic imidazole framework ZIF-7 (Zn(benzimidazole)2) was known to have gate-opening phenomenon, which make it be utilized in CO2 separation technology. Beside this distinctive gas adsorption property, ZIF-7 can be used also as a catalyst. In this study, we found ZIF-7 shows promising catalyst at the methoxycarbonylation of aniline with dimethyl carbonate (DMC) to produce methyl phenyl carbamate (MPC). Fresh ZIF-7 showed high aniline conversion over 95% at 190 oC for 2 h, the yield MPC was 60 - 70%. However, interestingly, when the ZIF-7 was reused, the yield of MPC increased over 94.7% by the catalyst’s 6th run. SEM and TEM images revealed the crystalline structure of ZIF-7 collapsed during the reaction. Based on 1H-NMR and XPS studies, it can be assumed that DMC binds to the Zn defect sites on ZIF-7, activating the carbonyl groups on DMC, resulting in the increased selectivity to methoxycarbonylation compared to methylation. |
