Synthesis of glycerol carbonate from glycerol and urea over lanthanum compounds

The synthesis of glycerol carbonate (GC) from glycerol and urea was investigated over a series of lanthanum compounds. Among them, LaCl3 showed the best catalytic activity. The conversion of glycerol could be 95.4 % with 99.9 % selectivity towards GC under the optimum reaction conditions. Then, it was found that for these catalysts, their solubility in the reaction system during reaction was the key to achieve high glycerol conversion and GC selectivity. Meanwhile, catalytic tests and FTIR measurements of the liquid phases after reaction confirmed that this approach could be divided into two steps, and the second one was the key step. Interestingly, it was revealed that some La-containing complex species could be formed via NH3 coordination to La3+ during the reaction. Furthermore, a possible reaction mechanism was proposed based on these systematic experimental results.