https://biointerfaceresearch.com/ 12858 Article Volume 11, Issue 5, 2021, 12858 - 12868 https://doi.org/10.33263/BRIAC115.1285812868 Synthesis of Biodiesel by Transesterification of Used Frying Oils (UFO) through Basic Homogeneous Catalysts (NaOH and KOH) Hamza Belkhanchi 1 , Mouhcine Rouan 2 , Maryama Hammi 3 , Younes Ziat 1 , Mohammed Chigr 2 1 Laboratory of Engineering and Applied Technologies, Higher School of Technology, Sultan Moulay Slimane University, Beni Mellal, Morocco 2 Laboratory of Organic and Analytical Chemistry, Sultan Moulay Slimane University, Faculty of Sciences and Technics, BP 523, 23000, Beni-Mellal, Morocco 3 University of Mohammed V, Laboratory of Materials, Nanotechnologies and Environment, Department of Chemistry, Faculty of Sciences, Avenue Ibn Batouta, P.O.B. 1014, Rabat, Morocco * Correspondence: maryama.hammichimie@gmail.com; Scopus Author ID 57219546880 Received: 21.12.2020; Revised: 15.01.2021; Accepted: 20.01.2021; Published: 31.01.2021 Abstract: The quest for an alternative sustainable source without petroleum technology and its refining has prompted the development of biofuels, such as biodiesel, from the transesterification of new or utilized vegetable oil. This work is devoted to the investigation of the transesterification of a used vegetable oil and optimization of the various parameters influencing the synthesis of biodiesel, such as the molar proportion (alcohol/oil), the amount of catalyst added and their weight percentage, the type of alcohol, the temperature T(°C) and the reaction time. From this standpoint, the current work's significant target is to propel the preliminary conditions of the transesterification response of fatty oils to create biodiesel from utilized vegetable oils. Diverse physicochemical characteristics were investigated (in terms of density, viscosity, acidity index, pour point, and flash point) to obtain biodiesel accordingly with international standards and commercial biodiesel. Keywords: biodiesel; vegetable oil; alkyl esters; flash point; pour point; acidity index; viscosity. © 2021 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). 1. Introduction The manufacture of biodiesel represents an alternative source of fuel production; which is known as renewable [1-4], biodegradable [5,6], sustainable [7], clean and non-toxic [8], the resources are abundantly available [9], neutral in CO2/GHG (greenhouse gases) [9-12], they cause negligible or zero SOx emissions [13,14], they provide lower NOx emissions [15,16], environmentally friendly [17,18], can be produced locally [19], they have a high flash point and less pollution [20-22], their production processes and/or biofuel farms are generally safe [23,24]. The applications of biofuels in life have been detailed in numerous publications [25– 28]. These applications have radically changed and improved the lives of people all over the world, especially in the automotive field where biodiesel can be used both as an alternative to conventional diesel or as an additive, neat or blended [29], it has less amount of pollutants during and after the combustion process. Engine life can be improved thanks to biodiesel viscosity twice as high as petroleum diesel [30], also during the combustion of biodiesel, the reduction of total unburned hydrocarbons is greater than 90% [31]. Biodiesel is produced by