Investigation of the Parameters Affecting Castor Oil Transesterification Reaction Kinetics for Biodiesel Production
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International Journal of Scientific & Engineering Research
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Kinetic studies are concerned with the quantitative description of how fast chemical reactions take place and factors affect-ing them. The study is important to a chemist to understand the fundamental aspects of the reaction pathways to achieve the desired product. It enables us to tailor a chemical reaction so as to produce the desired product in a controlled manner. Castor oil was trans-esterified with methanol using a molar ratio of methanol to oil (6:1) and sodium hydroxide catalyst (1% wt of oil). The product of the reaction is castor methyl ester (CME) and glycerol with diglyceride and monoglyceride as intermediate products. The experiment was set to determine the effect of temperature, stirring rate and residence time on the rate constants and a second order rate law was used. Four different temperatures (35, 45, 55 and 65C) and four stirring rates (600, 660, 700 and 800 rpm) were used and the reac-tions were timed. High temperatures (55 and 65C) were unfavourable for castor transesterification; both temperatures provided yields of 91%. Low temperatures (35 and 45C) increased rate constants and produced highest yields (98% and 97% respectively). Increas-ing stirring rate does not favour conversion rates. The optimum reaction time was 60 minutes. Beyond 90 minutes, the reverse reac-tion was favoured. The close fit of the data indicates that the selected model was adequate. These results agree well with reports from literature.
Keywords
Castor Methyl Ester, Castor Oil, Kinetics, Rate Constants, Second Order Rates, Transesterification