Conference Dates

March 8-13, 2009


Biodiesel is a fuel derived from the oils and fats of plants and animals. Some vegetable oils after extraction and seed storing may have high acidity due to the conversion of triglycerides into free faty acids. Transesterification of high acidic oils with basic catalyst will form a large amount of soap as residue. The objective of this work is to study hydrolysis of tallow fats estherification free fatty acids followed by estherification of free fatty acids with ethanol using homogeneous catalyst. Tallow fat was hydrolyzed by enzyme lipase extracted from Ricinius Communs seeds. Estherification was done in a pressurizes reactor, at temperatures from 70°C to 130°C, ethanol/oil ratio from 2:1 to 4:1, amount of sulfuric acid catalyst from 0.2 to 0.8%, during 60 minutes of reaction. A factorial experimental design was carried out with three variables, two levels and replicas at central point. Results show that hydrolysis with enzymes during 24 hours at 40 oC was very effective to convert triglycerides into free fatty acids (FFA). In the estherification reaction, the yield of esther increased with the increasing of temperature, ethanol/oil ratio and catalyst concentration. Best results was obtained at 130 oC and 0.8% of catalyst in either concentration of ethanol, 2:1 or 4:1. The mains effects on the FFA conversion was temperature, acid concentrations and cross effects temperate and acid concentration. Keywords: biodiesel, estherification, tallow, free fatty acid.