Preparation and Evaluation of Biodiesel from Sterculia foetida Seed Oil

Sterculia foetida oil contains cyclopropene fatty acids namely 8,9-methylene-heptadec-8-enoic acid (malvalic) and 9,10-methylene-octadec-9-enoic acid (sterculic) to an extent of 50-55%. The present study reports the preparation of biodiesel from S. foetida oil using sodium hydroxide as catalyst. The resultant biodiesel was evaluated for physico-chemical properties namely iodine value (72.6), free fatty acids (0.17%), phosphorous content (0 ppm), flash point (179 degrees C), cloud point (3 degrees C), pour point (3 degrees C), viscosity at 40 degrees C (4.72 cSt), oxidative stability at 110 degrees C (3.42 h), density (0.850 g/cm(3) at 15 degrees C), and trace metals (Group I metals 0.21 ppm). The properties were compared with that of sunflower, soybean and rapeseed oil-based biodiesels and found to be comparable except for the pour point.