Fuel additives from glycerol etherification with light olefins: State of the art

The production of biofuel has increased considerably over the last years. Glycerol, a by-product of biodiesel synthesis, accounts for 10wt% of the total product and has a limited range of applications. Etherification reaction of glycerol with light olefins (isobutene, isoamylenes) in liquid phase and catalyzed by acidic macroporous ion-exchange resins could be an attractive solution (i) to address the excess of glycerol, and (ii) to increase the diesel volume using light olefins, obtaining a product of good properties, higher value and especially useful as an additive in diesel and also in biodiesel. In order to study accurately the etherification of glycerol with isoamylenes, we conducted an extensive literature research to develop our understanding on glycerol etherification with light olefins. We realized that only isobutene without and with solvents and tert-butyl alcohol had been investigated experimentally in detail. This paper shows different synthetic routes, raw materials and experimental conditions to obtain good selectivities to ethers and high glycerol conversion.