Water glass derived catalyst for the synthesis of glycerol carbonate via the transesterification reaction between glycerol and dimethyl carbonate

Abstract

Water glasses with different modulus (mole ratio of SiO₂ to Na₂O) were applied as a raw material to prepare five solid base catalysts for the syn­thesis of glycerol carbonate (GC) by the transesterification reaction between glycerol and dimethyl carbonate (DMC). The structure and properties of the five water glass-derived catalysts were investigated by XRD, FT-IR, FESEM, BET and acid–base titration methods. The catalysts with relatively low mod­ulus, including 1.0, 1.5 and 2.0, presented good catalytic abilities, among which the catalyst derived from water glass with 2.0 modulus (WG-2.0) was chosen as the optimal catalyst in the synthesis of GC. This was because WG-2.0 showed the highest BET surface area, relatively high total basicity, and needed a less amount of NaOH during the preparation process. In the opti­mization experiments, this catalyst exhibited good catalytic ability with the glycerol conversion of 96.3 % and GC yield of 94.1 % under the condition of glycerol to DMC mole ratio of 1:4, WG-2.0 amount of 4 wt. %, reaction tem­perature of 348 K and reaction time of 90 min. Furthermore, the reusability experiment of WG-2.0 was also conducted and the results indicated that WG-2.0 could be reused five times without significant reduction in its catalytic ability.