Yacob AR, Mohmedahmed AMS, Azam bin M, Zaki M
Clay and clay minerals have very promising future in catalysis of chemical reactions. In this work Jourdiqua clay from north of Sudan was acid modified and used as heterogeneous catalyst in transesterification reaction of castor oil with methanol. The clay was modified with hydrochloric acid, HCl. at 30%, 40%, 50%, 60% and 70% weight concentration with respect to the clay, respectively. The raw and acid modified clay were characterized by Fourier transform infrared analysis (FTIR), field emission electron microscope (FESEM), back titration, TPD-NH3 technique and nitrogen adsorption desorption (BET) analysis, to determine the physico-chemical properties and the acidity of the raw and modified clay. The surface area and active sites of the modified clays were found to increase with the acid treatment. Transesterification of castor oil with methanol were done under the reaction condition of 9% w/w catalyst loading, methanol to oil molar ratio of 18:1, 3 h reaction time and the reaction temperature of 67°C. The biodiesel yield was monitored using nuclear magnetic resonance 1HNMR spectroscopy. The highest conversion observed is 83.86% achieved by 50% HCl/Clay.