280655 Homogeneous Esterification of Isoamyl Alcohol with Salycilic ACID, Kinetic Study

Wednesday, October 31, 2012
Hall B (Convention Center )
Yurany P. Jiménez1, Yohana Paez2, Alvaro Orjuela3 and Gerardo Rodriguez1, (1)Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Bogotá, Colombia, (2)Department of Chemical and Environmental Engineering, Universidad Nacional de Colombia, Bogotá, Colombia, (3)Department of Chemical and Environmental Engineering, Universidad Nacional de Colombia, Bogota, Colombia


Yurani Jiménez, Yohana Páez, Gerardo Rodríguez, Alvaro Orjuela.

Grupo de Procesos Químicos y Bioquímicos, Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Bogotá D.C, Colombia.


Fusel oil is obtained as by-product of ethanol production from the sugar cane in the final distillation stage[1]. Its quantity and composition is defined according to the conditions in the fermentation stage, being the yield of fusel oil in different sugar mills in Colombia about 0.1 to 0.5 % with respect to the volume of ethanol  produced [2-3]. Fusel oil is a mixture of several alcohols, mainly C3, C4 and C5, aliphatic alcohols where amyl alcohols reach 80% [9].  

Currently fusel oil is mainly used as energetic source, solvent and for coatings production[2, 4]. However, those applications represent low economic benefit and environmental problems. Taking this into account there is a potential benefit in implementing alternative processes to transform fusel oil into high added value products (i.e. esters) such as  isoamyl esters [4-5] [6], [7-8] which can be used as fragrances, solvents, plasticizers coating, flavoring, cosmetics and others.

One of those Isoamyl esters is Isoamyl Salicylate, a colorless liquid with diverse applications in food, cosmetics and fragrances industries because of its clover-like and orchids-like odor. This ester is currently produced by BASF in different grades (FCC, Kosher and natural) with purity greater than 98% and has a global market around 1000 metric tons annually [1]. Traditional synthesis process in the flavor industry uses concentrated sulfuric acid as catalyst. However, this catalyst generates high risks due to the difficulty of handling, high degree of darkening of the product due to oxidation, high waste generation and consequently some environmental impacts [4].

In this work, the kinetic study of the esterification reaction between salycilic acid and isoamyl alcohol using p-toluenesulfonic acid (PTSA) as catalyst is studied. The esterification reaction was carried out at temperatures between 368.15 K and 399.15 K, the catalyst loading was varied between 2 to 4 %, using molar ratio 6:1 to 8:1 (alcohol: acid), reaching conversion above 80%. Due to the non ideality of the reactive mixture, the activity coefficients were estimated using UNIFAC DOURMUND group contribution method. The pseudo homogenous kinetic model was fitted obtaining an error about 9.7%, using the ideal and non ideal pseudo homogeneous model.

Keywords: Esterification, kinetics, pseudo homogeneous model.



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