possible contribution of a homogeneous catalytic action of active zinc species leached into solution, hot catalyst filtration test was performed after 3 h of reaction. As shown in Fig. 6, no further AGE conversion in the filtrate occurred after catalyst removal at the reac- tion temperature, indicating that catalysis is not due to the soluble homogeneous species [35].
The effects of catalyst amount on the reactivity of F-ZIF-90 for the cycloaddition of CO2 and AGE were studied under semi- batch operation at 120◦C with CO2 pressure of 1.17MPa and the results are shown in Fig. 7. Catalyst amounts varying from 5 to 40 mg which proportionately corresponds to 0.24 wt% (relative to AGE) to 1.9 wt% were investigated. The catalytic activity was found to be increasing with increase in the catalyst amount from 5 mg (0.24 wt%) to 20 mg (0.95 wt%) resulting from the increase in num- ber of active sites available. Thereafter the increase in the catalyst amount does not show significant increase in the AGE conversion suggesting that 0.95 wt% is adequate enough of F-ZIF-90 effective for cycloaddition of AGE with CO2.
The effects of reaction temperature on the synthesis of AGC were studied using F-ZIF-90 catalyst at the semi-batch operation, and the results are shown in Table 3. The conversion of AGE and the selec- tivity to AGC increased as the temperature increased from 60◦C to 120◦C. However, over 140◦C, the conversion remained nearly constant and the selectivity decreased. Therefore, all the following experiments were carried out at 120 ◦ C. The main reaction byprod- uct was 3-allyloxy-1,2-propanediol.
The effects of CO2 pressure on the reactivity of F-ZIF-90 at 120 ◦ C after 6 h of reaction in the semi-batch reactor are shown in Table 4. The conversion of AGE increased as the CO2 pressure increased