Conversion of Biodiesel By-Product Glycerol to Fuel Ethers over Different Solid Acid Catalysts

In this study, the etherification reaction of glycerol (G) with tert-butyl alcohol (TBA) was investigated for the production of high quality transportation fuel additives. The reaction was carried out in liquid phase, in a continuous flow reactor in the presence of various solid acid catalysts. Activities of acidic resin catalysts, such as Amberlyst-15 (A-15), Amberlyst-16 (A-16) and Amberlyst-35 (A-35), Nafion-SAC-13 and ?-alumina were compared. Significant increase in conversion was observed with an increase in temperature. Amberlyst 15 showed the highest activity at about 110°C, giving glycerol conversion values of about 0.5 at a space time of 18 g cm-3 s. However, A-16 gave higher di-ether selectivity values. Nafion-SAC-13 showed activity at higher temperatures, while the activity of ?-alumina was very low, even at 400°C.