Structure-activity correlations of LiNO3/Mg4AlO5.5 catalysts for glycerol carbonate synthesis from glycerol and dimethyl carbonate.

MgAl hydrotalcite synthesized via co-precipitation method from magnesium and aluminum nitrates was calcined to produce Mg 4 AlO 5.5 mixed oxides. The oxides were modified by introducing LiNO 3 and applied to the synthesis of glycerol carbonate from glycerol and dimethyl carbonate. The research results indicated that LiNO 3 /Mg 4 AlO 5.5 was an efficient catalyst for the synthesis of glycerol carbonate. The full conversion of glycerol and 96.28% yield of glycerol carbonate were obtained after reacting at 80 °C for 1.5 h in the presence of LiNO 3 /Mg 4 AlO 5.5 . The structure and properties of the catalysts were studied by means of XRD, TGA, BET, CO 2 -TPD and Hammett indicator method. It was found that the basic strength and the basicity of the catalysts were enhanced after addition of LiNO 3 . Over Mg 4 AlO 5.5 oxides, LiNO 3 was easily converted to LiAlO 2 which constituted new strong basic sites. Too high basic strength and basicity of catalysts may improve the conversion of glycerol at the cost of GC selectivity reduction. [ABSTRACT FROM AUTHOR]