Synthesis of bio-lubricant form waste cooking oil

The increase of ecological concern inspires research of raw materials from renewable sources in lubricant industry. Therefore biodegradable lubricants produced from natural oils and fats become important. One of solution is by producing biolubricant. Bio-lubricant is a lubricant that use typically natural material such as vegetable oil as their base oil. Lower prices of waste natural oils and fats makes biodegradable lubricants much more competitive on the market. In this work the synthesis of bio-lubricant from waste cooking oil (WCO) through hydrolysis producing free fatty acid (FFA) and chemical esterification of FFA with trimethylolpropane (TMP) will be presented. In hydrolysis step, the operating parameter was observed such as reaction time and temperature of reaction from 30⁰C to 45⁰C. The optimum operating condition of hydrolysis reaction was determined where specific reaction time was at 4 hours, 45⁰C, 250 rpm and oil to water molar ratio, 1:3 and pursued with esterification. In esterification similar parameter was observed and obtained at optimum of, and the effect of temperature to the reaction will be observed. While for esterification process the characteristics of lubricant is studied using gas chromatography. At optimum operating condition, 90⁰C, 600 rpm and FFA to TMP molar ratio, 3:1, component with highest composition in the bio-lubricant is cyclohexyl isohexyl ester with 71%. Within 4 hours, the conversion of FFA to bio-lubricant reach 81%. Hence, the development of two-step process has a potential to be used industrially as it can tolerate feed stocks containing a wide range of FFA and water and also provide way of waste utilization.