Comparison Between SBA-15 and MCM-41 Structure on the Stability and the Selectivity of Basic Catalysts in Oligomerization of Glycerol

The oligomerization of glycerol to di- and triglycerol is an attractive reaction because these products find many applications in cosmetics, food industry and polymer industry. To control the oligomerization degree, it is necessary to develop a selective catalyst. In this work, two cesium mesoporous silica (MCM-41 and SBA-15) are compared in the selective oligomerization of glycerol into di- and triglycerol. The catalysts were prepared by incipient-wetness impregnation. The results showed that the stability and the activity of catalysts depend on the support nature. The use of SBA-15 support instead of MCM-41 leads to a more stable catalyst without changing polyglycerols selectivity. Different characterizations showed that it is due to the larger wall thickness of SBA-15. This study also showed that the nature of catalyst could influence the diglycerol isomers distribution. In fact the glycerol activation inside or outside the pores can strongly modify the selectivity to linear or branched diglycerol isomers.