Modelling the Kinetics of Jatropha Oil Transesterification

Abstract

Kinetics of a chemical reaction provides an important means of determining the extent of the reaction and in reactor designs. Transesterification of jatropha oil with methanol and sodium hydroxide as a catalyst was conducted in a well mixed reactor at different agitation speeds between 600 and 800 rpm and temperature range between 35˚C and 65˚C. The effect of variation of temperature and mixing intensity on rate constants were studied. The initial mass transfer controlled stage was considered negligible using the above impeller speeds and second order mechanism was considered for the chemically controlled kinetic stage. Samples were collected from the reaction mixture at specified time intervals and quenched in a mixture of tetrahydrofuran (THF) and sulphuric acid. The mixture was centrifuged at 2000 rpm for 15 minutes and the methyl ester was separated from the glycerol. The ester was washed with warm water (50˚C), dried and analysed using gas chromatography coupled with flame ionization detector (GC/FID) to determine free and total glycerine and methyl ester. A mathematical model was fitted using second order rate law. High temperature and high mixing intensity increased reaction rates. The model fitted well with a high correlation coefficient (R 2 ) of 0.999.

Sodium Silicate Catalyst for Synthesis Monoacylglycerol and Diacylglycerol-Rich Structured Lipids: Product Characteristic and Glycerolysis–Interesterification Kinetics

“…The Arrhenius equation demonstrates the correlation between temperature and the reaction rate constant, as stated in equation (9). Since the value of k4 (Table 3) was mostly zero for reaction at temperature 90 to 120 °C, it can be concluded that reaction (2) is irreversible.…”

“…The relationship between temperature and reaction rate constant was shown by the Arrhenius Equation ( 9). (9) where, k is the reaction rate constant, A is the exponential factor, Ea is the activation energy, R is the ideal gas constant, and T is the reaction temperature. From the Arrhenius Equation ( 9) it can be linearized as in Equation ( 10), so that the value of the activation energy (Ea) and the exponential factor (A) can be obtained.…”

“…Some importance kinetic studies on glycerolysis-interesterification are to understand the reaction mechanism, develop a mathematical model of the reaction rate, and evaluate the operating parameters of the system [7]. Reaction kinetic studies are generally carried out by Arrhenius equation, in which different operating conditions lead to various Arrhenius parameters [8][9][10][11][12][13][14]. Although the reaction kinetic studies of numerous types of fat and oil had been widely reported previously, the analysis of blended fat or oil has not been much reported yet [12][13][14][15].…”

High shear reactor for glycerolysis—Interesterification palm stearin‐olein blend: Reaction kinetics and physical properties

“…It proves that temperature changes influence reaction kinetics. Temperature is a crucial external parameter in a macroscopic approach, where the reaction temperature has an exponential relationship with the reaction rate constant (Okullo & Temu, 2015).…”