This study compared the yield of biodiesel produced from tall oil fatty acids (TOFA) via (i) homogeneous catalyst (sulfuric acid) and (ii) a heterogeneous catalyst (Amberlyst® BD20, together with Ambersep BD 19 (Midcontinental Chemical Co., Olathe, KS, USA)® using a batch reactor. The effect of operation conditions including temperature, catalyst concentration, methanol: oil ratio and reaction time on esterification yield were investigated. Gas chromatographic data showed that the major fatty acids present in the TOFA are oleic acid (C18:1n9) and linoleic acid (C18:2n6). Homogenous catalysis yielded 96.76% biodiesel compared to 90.24% for heterogeneous catalysis. Optimized conditions for homogenous catalysis were at a catalyst concentration of 0.5 w/w%, 15:1 methanol: oil mass ratio at 55 °C for 60 min. FTIR results also showed that the homogeneous catalyst yielded a more complete reaction toward biodiesel production in a shorter time (60 min) compared to the heterogeneous catalyst (4.7 h). For heterogeneous catalysis, the highest yield and the lowest acid value were achieved after a second recycling because the reactants were not fully in contact with the catalyst during the first recycling. The catalyst did not show a reduction in catalytic activity even after the fourth recycling. However, the acid value was higher than that for ASTM standards for biodiesel.

Highlights Tree fruit oils of Allanblackia spp., shea butter and palm kernel were evaluated for their physical and chemical properties using DSC, TGA and FTIR. All oils were thermally cycled to investigate their stability and reliability for potential use as phase change materials (PCMs) for thermal energy storage. Allanblackia spp. oil demonstrated greatest potential for use as PCM in thermal energy storage systems.

Research into biodiesel as a substitute for petroleum diesel has been ongoing since the energy crisis of the 1970's. The concern for the effect on the use of edible vegetable oils as feedstock has increased. Tall oil fatty acids have been considered as a non-food substitute and various works have been done on it. In this study, sulfuric acid and Amberlyst BD 20 were used as homogeneous and heterogeneous catalysts respectively in the production of biodiesel from Tall oil fatty acids in a batch reactor. The treatment conditions for the homogeneous catalysis varied the factors of fatty acid to methanol molar ratio, the temperature, the catalyst concentration and the time of the reaction. Fourier transform infrared (FTIR) spectroscopy was used to monitor the reaction in real time to show when conversion of reactants to products is complete. Gas chromatography showed the fatty acids present in the oil sample. The major fatty acids present are oleic and linoleic acid. Acid value, the kinematic viscosity, and specific gravity were all determined. The heterogeneous catalysis kept the temperature of the reaction constant within 75-80 o C. The molar ratio, catalyst concentration and time of reaction were varied. Results showed vi TABLE OF CONTENTS LIST OF TABLES .