Pembuatan Metil Ester Asam Lemak melalui Reaksi Transesterifikasi pada Perbandingan Rasio Molar Metanol : Minyak Sawit Menggunakan Katalis K2O/SiO2

Abstract

The production of fatty acids methyl ester from palm oil has been carried out through transesterification reaction of solid sludge waste from the municipal water supply (PDAM) via impregnation method with KOH to yield K2O/SiO2 catalyst. The solid sludge waste was calcined at 800°C for 3 hours and analyzed by X-ray Fluorescence (XRF), revealing the main components as SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O, and K2O, with SiO2 being the predominant component at 50.7%. The study investigated different oil to methanol ratios (1:6, 1:9, 1:12, 1:15) with a catalyst loading of 5% w/w for 2 hours. The conversion of fatty acid methyl esters was analyzed by chromatography gas, while the transformation of functional groups from oil to fatty acid methyl esters was determined by Fourier Transform Infrared (FT-IR) spectroscopy. The highest conversion of fatty acid methyl esters was achieved at an oil to methanol molar ratio of 1:15, reaching 99.23% at a reaction temperature of 60°C with a catalyst loading of 5% w/w for 2 hours. The highest conversion and yield of fatty acid methyl esters were obtained at a molar ratio of 1:15, catalyst loading of 5% w/w, and reaction time of 2 hours, yielding 81.61%. The formation of fatty acid methyl esters was indicated by the shifting of -C-O-C- vibration peaks in the 1300-1000 cm-1 range, where in oil, the strongest absorption among the three peaks occurred at the middle position, while in fatty acid methyl esters, it shifted to the rightmost position.