Monodisperse mesoporous La2O3 flakes for the synthesis of glycerol carbonate by efficiently catalyzing the transesterification of dimethyl carbonate with glycerol

摘要

Monodisperse mesoporous La2O3 flakes were prepared by hydrothermal methods using polyethylene glycol as pore-expanding agent, the catalyst exhibited better catalytic activity than normal La2O3 in the reaction of glycerol and dimethyl carbonate to produce glycerol carbonate. The influence of the molecular weight of polyethylene glycol and the mass ratio of La(NO3)(3)center dot 6H(2)O/polyethylene glycol on the catalyst was investigated. The results showed that the morphology of La2O3 was remolded to porous flakes interestingly by the suitable type and dosage of pore-expanding agent, this change made the La2O3 catalyst particles have higher alkalinity, better crystallinity, larger specific surface area and good dispersion, which greatly improved the catalytic performance of the catalyst. In addition, the optimal reaction conditions were studied. As a result, the as-prepared porous La2O3 modified by polyethylene glycol-20000 showed excellent catalytic performance with high glycerol carbonate yield of 99.4% under the optimal reaction conditions as follows: the glycerol/dimethyl carbonate molar ratio was 1:5, the catalyst dosage was 5.0 wt% to glycerol, the reaction temperature was 85 degrees C and the reaction time was 0.5 h. The catalyst had outstanding stability after six cycle reactions with almost no loss of catalytic activity. Thereby, the catalyst was considered to possess the promising potential in industrial production for catalyzing glycerol to the high value-added chemical glycerol carbonate.