A STUDY ON ACID-CATALYZED TRANSESTERIFICATION OF CRUDE RICE BRAN OIL FOR BIODIESEL PRODUCTION

Biodiesel is a renewable, biodegradable and nontoxic fuel for diesel engines. It is derived from oils and fats by transesterification with alcohols. As alternative fuel biodiesel has attracted considerable attention during the past decades. The main hurdle to the commercialization of biodiesel is the cost of raw materials. The high value of soybean oil or canola oil as a food product makes production of a cost-effective fuel very challenging. Use of edible oils as biodiesel feedstock cost about 60-70% of raw material cost. Nonedible, inexpensive, low-grade oils with value added byproducts is utmost important to make the biodiesel production economical. Rice bran oil ranks first among the non-conventional, inexpensive, low-grade vegetable oils. Furthermore, crude rice bran oil is a rich source of high value-added byproduct. Therefore, use of rice bran oil as raw material for the production of biodiesel not only makes the process economical but also generates value added bio-active compounds. Isolation and purification of these byproducts make the process attractive and remunerative.In the present investigation a systematic studies of transesterification of high free fatty acid rice bran oil was carried out to establish optimal reaction condition. It was found that acid-catalyzed methanolysis of fatty acids are faster than pure triglycerides or pure triglycerides plus 5% water. More than 99% of FA were converted to their corresponding FAME with 20 min of reaction times at temperature of boiling point of methanol otherwise almost for 6 hours reaction none of TG were converted. Effect of chain length and unsaturation of fatty acid on rate of esterification of fatty acid with methanol are equally reactive irrespective of difference in their chemical structures. Fatty acids from different sources shows similar conversions and change in the fatty acids composition has no effect on rate of methanolysis.