Biodiesel from Oleic Acid by Green Catalyst "Catalytic Membrane": a Solution to Global Warming Problems

In recent years biodiesel is receiving more attention as a sustainable alternative to fossil fuel. Biodiesel has lower exhaust emissions and toxicity compared to petroleum diesel fuel. In this study, biodiesel is produced from the oleic acid esterification process. We try to develop an efficient heterogeneous catalyst for biodiesel synthesis. A catalytic membrane carboxymethyl cellulose with sulfosuccinic acid has been prepared for using as catalyst. Carboxymethyl cellulose is a natural and biodegradable polymer and it has the advantage of green catalysis. Sulfosuccinic acid is a homogeneous catalyst. To overcome the disadvantages of the homogenous catalyst, sulfosuccinic acid is used together with polymeric membranes. The effects of the ethanol/oleic acid molar ratio, the reaction temperature, the sulfosuccinic acid concentration and the stirring speed were investigated to find out the optimum reaction conditions. The catalytic stability of the catalytic membrane is also studied. The optimum conditions for the reaction were found to be 65°C, catalytic membrane with 6 mmol of sulfosuccinic acid, 9:1 ethanol to oleic acid molar ratio and 600 rpm stirring speed. The oleic acid conversion using the catalytic membrane was 85% under these conditions after 6 h. Our findings show that carboxymethyl cellulose membrane with sulfosuccinic acid groups is a suitable catalyst for esterification.