Formulation of new high quality fuels by etherification of glycerol which is a by-product in biodiesel production

Biodiesel is a mixture of fatty acids methyl esters which is produced by transesterification of vegetable/animal oils with methanol/ethanol and has gained importance as an alternative to diesel fuel for motor vehicles in recent years. Glycerol (G) is the major by-product of biodiesel production and the use of biodiesel as a fuel alternate may be feasible if glycerol can also be converted to valuable products such as high quality fuel additives. In the present study, the etherification reaction of glycerol with tert-butyl alcohol (TBA) which is also a by-product in the ARCO process was investigated to produce high quality motor vehicle fuels and fuel additives. The etherification reaction of glycerol was carried out in a continuous flow reactor using acidic resin catalysts such as Amberlyst-15 and Amberlyst-16. Effects of reaction temperature (80-110ºC), feed composition (TBA/G=3/1-8/1) and space times (6, 8, 12, 16, 18, 24 g s cm-3) on the product distribution were investigated. The highest conversion of glycerol was achieved on Amberlyst-15 when the molar ratio of reactants was 8/1 at 110 ºC. Mono- ethers, di- ethers and tri- ether were obtained in the study. The selectivities of the products didn?t change with different reaction parameters. Over Amberlyst-16 the the highest amount of di- and tri- ethers (desirable products) was formed due to its lower acidity.