THE EFFECTIVE PROCESS OF WASTE COOKING OIL BIODIESEL PRODUCTION BY INTERESTERIFICATION WITH REACTION USING CURCUMIN BIOCATALYST

Abstract

Biodiesel is a renewable energy source that can replace fossil fuels. Used cooking oil is the most relevant biodiesel feedstock because it is a waste product. The interesterification process for biodiesel production uses a catalyst that requires separation at the end of the reaction, making it less effective. A more effective and economical biodiesel production process using waste raw materials, without the separation of by-products and catalysts, is needed to overcome this problem. Organic aromatic compound biocatalysts are environmentally friendly and relatively inexpensive. Compound biocatalysts eliminate the need for a separation process and any residue left in the biodiesel can be beneficial, as these substances act as antioxidants preventing an increase in oxidation number. In this context, curcumin is an organic aromatic compound with two aromatic groups. Therefore, this research obtains rational conditions for the interesterification reaction of waste cooking oil with curcumin biocatalyst. The operating conditions included 250 grams of waste cooking oil, the mass of curcumin biocatalyst was 0.5, 1, 1.5, 2, and 2.5%, 300 rpm stirring speed, mole ratio of methyl acetate oil was 1:6 and 1:12, reaction temperature 60°C as well as reaction time of 15, 30, 45, 60, 75, 90 and 105 minutes. The results show that the highest crude yield was obtained at 91.74% in the interesterification reaction of waste cooking oil with a curcumin biocatalyst concentration of 2.5% at a reaction time of 105 minutes and the mole ratio of oil:methyl acetate = 1:6. A density value of 0.884 g/ml and an acid number of 0.224 mg KOH/g were obtained which met SNI 7182-2015 under these conditions. In addition, the outcome of the GC-MS analysis shows that the dominant methyl ester component formed was hexadecanoic acid, 1-methylethyl ester