2.2. One-step synthesis of biodiesel from karanja oil
A mixture of karanja oil (1 g, with 7.5% FFA), CH3OH (2.0 ml) and carbon acid catalyst (200 mg, 20 wt.% of oil) was taken in an ACE pressure tube and heated at 160 _C by immersing in oil bath with electrical heating under magnetic stirring for 4 h. The progress of the reaction was monitored by TLC and Gas chromatography (DB-5HT). After completion of the reaction, the catalyst was separated by filtration for reuse and the reaction mixture was washed with water. The organic phase was dried over sodium sulphate and the solvent was removed under reduced pressure to obtain biodiesel. Composition of monoglyceride (MG), diglyceride (DG), triglyceride (TG) and fatty acid methyl ester (FAME) present in the reaction product obtained under different reaction conditions was determined by Gas chromatography using DB-5HT capillary column (30 m, 320 lm id, 0.1 lm film of (5% phenyl)-methylpolysiloxane). Employing the optimum reaction conditions, karanja oil biodiesel was prepared in 150 g scale using 600 ml pressure reactor maintaining at 8–10 kg pressure for the determination of biodiesel properties. Karanja oil (150 g), catalyst (30 g) and methanol (300 ml) were charged into 600 ml pressure reactor and heated to 160 _C under stirring (350 rpm) for 4 h. Reaction was cooled to room temperature and the reaction mixture was discharged and separated the catalyst by filtration. The reaction product was concentrated by distilling out the methanol under reduced pressure and washed with water to remove glycerol. The biodiesel was dried and analyzed for acid value and biodiesel properties.