Kinetic Study of Catalytic Esterification of Butyric Acid and Ethanol over Amberlyst 15

The esterification reaction of butyric acid with ethanol has been studied in the presence of ion exchange resin (Amberlyst 15). Ethyl butyrate was obtained as the only product which is used in flavours and fragrances. Industrially speaking, it is also one of the cheapest chemicals, which only adds to its popularity. The influences of certain parameters such as temperature, catalyst loading, initial concentration of acid and alcohols, initial concentration of water, and molar ratio were studied. Conversions were found to increase with an increase in both molar ratio and temperature. The experiments were carried out in a batch reactor in the temperature range of 328.15–348.15？K. Variation of parameters on rate of reaction demonstrated that the reaction was intrinsically controlled. Experiment kinetic data were correlated by using pseudo-homogeneous model. The activation energy for the esterification of butyric acid with ethanol is found to be 30？k？J/mol. 1. Introduction Organic esters are important fine chemicals used widely in the manufacturing of flavors, pharmaceuticals, plasticizers, and polymerization monomers. They are also used as emulsifiers in the food and cosmetic industries. Several synthetic routes are available for obtaining organic esters, most of which have been briefly reviewed by Yeramian et al. [1]. Several synthetic routes have been used to make organic ester, but the most-used methodology for ester synthesis is direct esterification of carboxylic acids with alcohols in the presence of acid/base catalysts. Esterification is used. The most acceptable method is to react the acid with an alcohol catalyzed by mineral acids, and the reaction is reversible [2]. Esterification of carboxylic acid with alcohol in the presence of acid catalyst has been the subject of investigation of many research workers [3]. The traditional industrial process of synthesizing esters using homogeneous acid catalyst is conveniently replaced by solid acid catalyst, ion exchange resins, clay, and so forth [4]. The ion exchange resin is a promising material for replacement of homogeneous acid catalysts. The use of ion exchange resins as solid catalyst has many advantages over homogeneous acid catalysts. They eliminate the corrosive environment; they can separate from liquid reaction mixture by filtration and have high selectivity [5]. They can also be used repeatedly over a prolonged period without any difficulty in handling and storing them. And the purity of the products is higher since the side reactions can be completely eliminated [6]. Fatty acid esters are used