Production, properties and fatty acids profile of some refined vegetable oils based biodiesels

Abstract

Utilizing varieties of non-edible vegetable oils such as Jatropha (Jatropha curcas; JSO), Neem (Azadirachta indica; NSO) and Castor (Ricinus communis; CSO) are attractive options to produce biodiesel economically, but, high free fatty acids (FFA) in the vegetable oils are serious issues for the transesterification. In this work, the physicochemical qualities of the three crude and refined jatropa oil, RJO; neem oil, RNO and castor oil, RCO were investigated to determine the influence of refining processes of degumming; alkaline and bleaching on their physicochemical qualities, respectively. Using the Association of Analytical Chemist (AOAC) and American Standard for Testing Materials (ASTM) standard techniques, while the trans-esterification reactions were monitored by Fourier Transform Infra-Red (FT-IR), the fatty acid methyl esters (FAME) quality assessment were obtained from the Gas Chromatography–Mass Spectroscopy (GC-MS). The results of the physicochemical properties of refined feedstock (RJO, RNO, RCO) compared with the crude (JSO, NSO, CSO) indicated higher percentage of improved quality over the feedstock in the parameters measured such as yield (56.0, 55.7, 58.3 %); acid value (1.122 mg/KOH); saponification value (179.6, 302.9, 261.0 mg/KOH); iodine value (26.7, 20.3, 37.9 I2/100g); peroxide value (2.4, 18.4, 8.8 Meq O2/kg); density (1.5, 1.3, 1.4 g/cm3); viscosity @ 40 oC (32.0, 58.9, 20.0 %); refractive index @ 30 oC (1.5, 1.5, 1.5 %), respectively. The physicochemical properties of the biodiesel showed similar trend in the quality that compared with the ASTM standard for biodiesels. The fatty acid profile assessment of refined feedstocks shows different 14 compounds with varying percentage composition (1.61 - 20.78 %) with oleic acid as the most abundant in RNO followed by ricinoleic acid (19.59 %) in RCO. The biodiesel produce here indicates better physicochemical improvements that may serve