Emine Sert

Esterification of acetic acid with methanol over a cation exchange resin

The esterification kinetics of acetic acid with methanol in the presence of ResinTech SACMP-H ion exchange resin as a heterogeneous catalyst were studied at temperatures of 303, 313 and 323 K. The effects of various parameters such as temperature, catalyst loading, stirrer speed and also the effect of the mole ratio of reactants, and the reaction mechanism, have been investigated in detail. The uncatalysed reaction was shown to be second-order reversible process. For heterogeneously catalysed reaction, three different kinetic models were applied to the experimental data, the best fit being the Eley-Rideal mechanism. It was found that ResinTech SACMP-H catalyst acts by reducing the activation energy from 58 to 48.2 kJ mol−1.

Kinetic Study of the Esterification of Acetic Acid with 1-Butanol Catalysed by Alumina-Supported Tungstophosphoric Acid

The kinetics of the esterification of acetic acid with 1-butanol in the presence of alumina-supported tungstophosphoric acid (TPA) was studied. The uncatalysed reaction was shown to proceed by a second-order mechanism. In the presence of the catalyst, the reaction was found to occur between an adsorbed alcohol molecule and a molecule of acid in the bulk fluid (Eley–Rideal mechanism). It was found that alumina-supported TPA is suitable for this reaction because the activation energy was reduced from 58.0 to 37.3 kJ mol−1. The catalyst was characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscope, nitrogen adsorption study and IR spectroscopy.

Determination of Adsorption and Kinetic Parameters for Butanol–Acetic Acid Esterification System Catalysed by Amberlyst 15

The esterification of acetic acid with butanol catalysed by Amberlyst 15 was studied over a range of catalyst loadings, temperature, molar ratio of reactants, stirrer speed and particle size of catalyst. The equilibrium constant was experimentally determined and the reaction was found to be exothermic. Swelling and adsorption studies were performed to estimate the adsorption constants. The values found for the adsorption constants follow the order: water > butanol > acetic acid > butyl acetate. Experimental kinetic data for the esterification were correlated with the Pseudohomogeneous (PH), Eley-Rideal (ER) and Langmuir-Hinshelwood-Haugen-Watson (LHHW) models. The activity coefficients were calculated according to the UNIQUAC method. A possible mechanism of this reaction involved following the Eley-Rideal mechanism in which an adsorbed and protonated butanol molecule reacts with an acetic acid molecule in the bulk. The activation energy of the forward reaction was found to be 45.4kJ mol−1.

An investigation of the production and lubricity characteristics of fatty acid esters.

The effects of operating parameters for the esterification of free fatty acids with butanol in the presence of sulfuric acid were studied. Experiments were carried out at catalyst loadings of 0.5, 1, and 7 wt% relative to reaction mixture, butanol/free fatty acids mole ratios of 1, 2, and 6 and the temperatures of 358, 368, and 378 K. Increase in reaction temperature, acid to alcohol ratio, and catalyst loading is found to enhance the conversion of free fatty acid. In this study, the prediction of esterification reaction mechanism is conducted by a complex acid model. The influence of temperature on the kinetic constants was determined by fitting the results to the Arrhenius equation. The energy of activation for the forward reaction was found to be 67.9 kJ/mol. Vegetable-based esters are potential biodegradable base stocks for environmentally friendly lubricants. The basic lubrication parameters, such as acid value, viscosity, viscosity index, color, copper strip corrosion, foaming, and demulsifying properties, were tested and compared well with commercial standards.