Effect of Reaction Parameters on Yield and Characteristics of Biodiesel Obtained from Various Vegetable Oils

Biodiesel is mono-alkyl ester (fatty esters) of long chain fatty acids derived from renewable biological sources such as vegetable oils or animal fats. The yield and characteristics of biodiesel depends on the type of oil used due to variation in the fatty acid composition and other characteristics of oil. In the present study, various vegetable oils were converted to biodiesel at various reaction conditions. Different types of oils from edible (sunflower, mustard, and groundnut) and non-edible sources (Jatropha with high and low free fatty acid contents) have been taken for preparation of biodiesel using KOH as catalyst and methanol as alcohol. Jatropha oil having high free fatty acid content was subjected to two step transesterification first using acid catalyst to reduce free fatty acid content and then using alkaline catalyst. Various reaction parameters such as alcohol to oil ratio, type and concentration of catalyst, temperature, and reaction time were taken to analyze their effects on the yield and the characteristics of biodiesel obtained. Reaction temperature of 70oC, reaction time of 1 hour, catalyst amount of 1 % (by weight of oil), methanol to oil molar ratio of 6:1 were found to be the best suitable conditions for maximum yield of biodiesel obtained from all the vegetable oils under consideration. Characteristics of biodiesel obtained at the optimum conditions are as per ASTM standards