Synthesis and Characterization of Biodiesel from Coconut Oil Using Homogeneous Catalyst

Abstract

The present project explains how crude biodiesel (crude BD) has been obtained by using coconut oil and ethyl alcohol as well as sodium hydroxide as a catalyst. The coconut oil was extracted with water which was submitted to evaporation afterwards. This experiment was carried out by adding the coconut oil in a 500 mL glass flask. The catalyst was dissolved in ethyl alcohol and mixed together with the coconut oil. Once obtained the mixture, this was stirred for 25 minutes at temperatures from 20, 30, 40, 50 to 60 °C. During the reaction, two phases were formed: crude biodiesel (top layer) and crude glycerol (bottom layer). The characterization was done by determination of pH (using an electrode located in the top layer connected to a computer by RS-232 interface system). When the separation concluded, the crude BD was rinsed in order to remove the catalyst. The characterization of washed biodiesel was determined by density and Saybolt viscosity. Fourier Transform Infrared (FTIR) analysis was also made. The results by FTIR indicated the two functional groups of fatty acid ethyl esters (C=O, 1733 cm-1 and C-O, 1154 cm-1) and the OH wide band group of glycerol at 3400 cm-1. When the reaction time ended, the maximum pH value registered was 12.7. The values for pH, density and Saybolt viscosity were acceptable for crude BD and crude glycerol.