Etherification of glycerol with ethanol over solid acid catalysts

Different types of acidic heterogeneous catalysts, including sulfonic resins, zeolites and grafted silicas are used for the synthesis of mono-ethers of glycerol using ethanol as the alcohol. The study shows that the performances of the catalysts are governed by both the acidity and the polarity of their surface. Materials with strong hydrophobic character are not active as they do not allow the adsorption of the glycerol. On the other hand a strong adsorption of glycerol on the polar surfaces leads to low activity as well. The best compromise has been found by using sulfonic-acid polystyrene resins of the Amberlyst family and zeolites with intermediate aluminium contents.