| 초록 |
Zeolitic imidazolate frameworks (ZIFs) are a large emerging class of porous crystalline MOFs with tetrahedral networks that resemble those of zeolites: transition metals (Zn, Co) replace tetrahedrally coordinated atoms (for example, Si), and imidazolate links replace oxygen bridges. The synthesis of cyclic carbonates from epoxides and CO2 under mild conditions have drawn much attention because of its 100 % atom economicity. ZIF-95 being a microporous material shows high affinity & capacity for CO2 adsorption. Here, in the present work we have prepared highly porous ZIF-95 crystals and employed it as a catalyst for the epoxide-CO2 cycloaddition. Synthesized ZIF-95 was characterized by various physicochemical methods. Cycloaddition reactions were carried out at 80 ℃ by using propylene oxide as substrate along with tertiary butyl ammonium bromide as co-catalysts. Results showed that nearly 83 % conversion was observed within 2 h with almost 100% selectivity. Different epoxide substrates were subjected to the cycloaddition using ZIF-95 catalyst.. The effects of different reaction parameters like catalyst amount, reaction time, reaction temperature, and CO2 pressure have been also investigated. |
