IOSR Journal of Applied Chemistry (IOSR-JAC) e-ISSN: 2278-5736.Volume 12, Issue 10 Ser. I (October. 2019), PP 01-04 www.iosrjournals.org DOI: 10.9790/5736-1210010104 www.iosrjournals.org 1 |Page Oil Esterification Using High-Free Fatty Acid Acid Using Hydrodynamic Cavitation Process Muhammad Rizal 1 , M D Supardan 1 , Yn Syamsyuddin 1 1 (Departement of Chemical Engineering/ Universitas Syiah Kuala, Indonesia) Corresponding Author: Muhammad Rizal Abstract: In thisstudy,the fattyacid methy lester was synthesized through the esterification stage. Esterification is the reaction between used cooking oil and methanol( CH 3 OH) using sulfuric acid (h 2 SO 4 ) as a catalyst to produce fatty acid methyl esters (FAME) and water. cooking oil waste used must have free fatty acid levels above > 2% so that the esterification process can be carried out. This research is focused on reducing the optimal levels of fatty acid methyl esters between the hydrodynamic cavitation process and the stirring process. a decrease in methyl ester fatty acids of 0.72% was obtained under reaction conditions (temperature 50 o C, 120 minutes, waste cooking oil /methanol ratio 1:10, catalyst amount 1% -w/w with process hydrodynamic cavitation). esterified methyl ester fatty acids can continue at the stage of the transesteri fication process for the manufacture of biodiesel. Keywords:, free fatty acids , waste cooking oil , esterification, hydrodynamic cavitation --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 24-09-2019 Date of acceptance: 12-10-2019 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Generally, the processes of biodiesel producing from vegetable oils are going through the stages of esterification and transesterification of oil so that it becomes biodiesel. Indonesia has many types of oil- producing plants that can be used as raw material for biodiesel, but some vegetable oils have poor quality with high free fatty acids (FFA) level. One type of oil is waste cooking oil [1]. Waste Cooking oil contains a lot of FFA which is produced from the oxidation and hydrolysis reaction during the frying process. The presence of free fatty acids in waste cooking oil can cause side reactions namely lathering reactions, which if in the process of making biodiesel directly using the esterification reaction. The greater the level of free fatty acids in oil, the worse the quality of oil will be. An esterification process with an acid catalyst is needed if vegetable oil contains FFA above 5%. If the FFA oil content is above of 5%, the esterification process is carried out so that it becomes a fatty acid methyl ester [2]. The esterification results can be affected by several factors, including: water content, free fatty acids, molar ratio of alcohol to raw materials, reaction temperature, amount and type of catalyst, reaction time, and the type of alcohol used [3]. The catalyst used in the esterification reaction is sulfuric acid (H 2 SO 4 ) because it is a strong acid where proton H + can be substituted and binds strongly with oxygen atoms in carbon carbonyl which have a large electronegativity value. The selection of methanol in the esterification process is based on its reactivity. This is because methanol is an alcohol compound with the shortest carbon chain. In which, the shorter carbon chain the alcohol used the higher the reactivity [4]. A number of technologies have been developed to produce biodiesel through an esterification reaction efficiently. The technology is using hydrodynamic cavitation techniques and ultrasonic waves[6]. Hydrodynamic cavitation is a phenomenon of the formation, growth and breakdown of micro bubbles in liquids that occur due to pressure variations in the flowing liquid resulting in changes to the geometry of the flowing system during the esterification process [7]. Hydrodynamic cavitation has several advantages, which is the most inexpensive and efficient method of using energy for cavitation formation, the equipment used in the formation of hydrodynamic cavitation is also simple [8]. The purpose of this study is to study the effect of the methanol mole ratio to cooking oil waste, temperature and processing time to decrease free fatty acid levels, study the kinetics of the esterification process reaction using hydrodynamic cavitation and compare the performance of the hydrodynamic cavitation esterification process with the stirring process. II. Methodology 2.1. Equipments and Chemicals The raw material was waste cooking oil (WCO) from Banda Aceh. The chemical compound used were methanol 96%(Merck Indonesia), Potassium hydroxide (KOH), Sodium hydroxide (NaOH), sulfuric acid 98%