BIODIESEL SYNTHESIS FROM PALM FRYING OIL WITH MODIFIED SILICA-BASED CATALYST

• Main Author: David
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/68088
• Institution: Institut Teknologi Bandung

Biodiesel is produced from the esterification of fatty acids or transesterification of triglycerides (oils) with short chain alcohols in the form of methanol or ethanol. Used palm cooking oil is one of the most attractive biodiesel raw materials because it is a waste so that it has a cheaper price and can reduce the cost of biodiesel production. In this study, a heterogeneous catalyst in the form of modified silica which has acid-base catalytic properties was used for the synthesis of biodiesel from palm cooking oil. The selection of heterogeneous catalysts aims to make the production process more environmentally friendly and reduce production costs because the catalyst has the potential to be used repeatedly. Heterogeneous acid catalysts have a higher tolerance for free fatty acids in oil samples than heterogeneous base catalysts, making them more suitable for use in the synthesis of biodiesel from low quality raw materials. The heterogeneous acid catalyst in this experiment was prepared by impregnation of HClO4 on SiO2. The reaction using SiO2-HClO4 catalyst was carried out under the conditions : oil to methanol molar ratio = 1: 20, the amount of SiO2-HClO4 catalyst = 4 % w/w [1% mol H+] at 65 °C for 6 hours. At a temperature ? boiling point of methanol and standard pressure, SiO2-HClO4 catalyst is less effective in synthesizing biodiesel from used palm cooking oil. Base catalysts are reported to be able to catalyze biodiesel reactions more efficiently under milder reaction conditions, so that in this experiment a heterogeneous base catalyst was synthesized in the form of desilicated zeolite by 1, 2, 3 and 4 M KOH solutions. The reaction with zeolite-based catalysts was carried out at conditions : oil to methanol molar ratio = 1 : 12, the amount of zeolite catalyst = 4 % w/w at a temperature of 65 °C for 2 hours. The alkaline catalyst in the form of desilicated zeolite by 1 M KOH solution gave the best results in this experiment using new palm cooking oil with 81,800 % yield and ? = 0,5583. This catalyst was then tested on synthesis of biodiesel from used palm cooking oil. To avoid saponification on the surface of the alkaline catalyst, the fatty acid content of the used palm oil cooking oil sample was reduced from 7,65 wt% to 2,89 wt% using an adsorbent in the form of 5 wt% bentonite in two stages. Unfortunately, this alkaline zeolite catalyst with the best performance still requires further development to be able to catalyze the synthesis of biodiesel from used palm cooking oil.