Abstract
The possibility of using restaurant trap grease as feedstock in the production of biodiesel via acid catalyzed esterifi- cation is explored in this study. Sulfuric acid was used as a catalyst for the esterification reaction of free fatty acid (FFA) and methanol. The FFA levels of restaurant trap greases were reduced from 60.38±2.22 mg KOH/g to 11.60±1.60 mgKOH/g when conditions for biodiesel production are as follow: methanol-to-FFA ratio of 5:1, 5 wt.% H2SO4, and a reaction temperature at 60°C with a reaction time of 60 min. During the acid-catalyzed esterification, the percentage of methyl esters resulting from conversion of FFA in the obtained product was 83.59±1.51% based on the result of 1H NMR analysis. Data obtained from the 23 full factorial designs revealed that methanol-to-FFA ratio term had the most significant effect on the percentage of methyl esters, followed by the H2SO4 concentration. Conversely, reaction time between 1 and 3 hours had no significant effect on the esterification of trap greases.
Keywords: waste greases, brown grease, methyl ester, factorial design, esterification