An Alternative to Methanol for Biodiesel Production from Sunflower Oil

Researchers from the Department of Chemical Engineering, Institute for Chemical and Environmental Technology (ITQUIMA), University of Castilla – La Mancha (Spain) have explored a new innovation in the production of biodiesel from sunflower oil. In the conventional method, the oils are reacted with methanol, using sodium hydroxide as catalyst. The products are the biodiesel (a mixture of methyl esters) and a by-product called, glycerol.

Instead of using the conventional methanol for the chemical process of biodiesel production, the researchers investigated the use of methyl acetate with potassium methoxide as catalyst to produce the biodiesel. Among the findings of their study were:

(1) the optimum conditions that created a compromise between the product yield, reaction kinetics and methyl acetate recovery were found to be a methyl acetate-to-oil molar ratio of 50 and a catalyst-to-oil molar ratio of 0.10;
(2) the reaction time was only 15 minutes with a corresponding mass fraction of 76.7% for FAME (the biodiesel product), 17.2% for the triacetin, 4.7% for the intermediate diacetinmonoglyceride and 1.2% for the diacetin, monoacetin and glycerol,
(3) the limiting step in the chemical interesterification is the dissolution of the catalyst in the reaction mixture,
(4) high amounts of the methyl acetate is required to shift the reaction equilibrium,
(5) the catalyst is easily deactivated in the presence of water.

The full study is published in the free-access journal, Biomass and Bioenergy (URL above).