Glycerol carbonate production from transesterification of glycerol with diethyl carbonate catalyzed by Ca/Al-mixed oxides derived from hydrocalumite

A series of Ca/Al-mixed oxides derived from hydrocalumite (HC) with Ca/Al atomic ratio of 2 was prepared by calcination at different temperatures and they were evaluated in transesterification of glycerol with diethyl carbonate (DEC) to produce glycerol carbonate (GC). HC was tested as non-calcined and calcined at different temperatures (600, 700, 800, and 900 degrees C). The catalysts presented a well-crystallized structure with low specific surface area. Non-calcined hydrocalumite presented higher density of basic sites (571 mu mol g(-1)) with major proportion of strong basic sites; after calcination, catalyst basicity dropped dramatically. Reactions were performed with different temperatures (from 90 to 130 degrees C), catalyst amounts (5, 10, and 15 wt%), and solvents (dimethyl sulfoxide and dimethylformamide). Promising results were found using HC calcined at 700 degrees C, reaching 90% of glycerol conversion and 91% of GC selectivity at 130 degrees C.