Acid catalysts based on simple modification of chitosan for the esterification of oleic acid

ABSTRACT Chitosan is a linear polymer with excellent physicochemical properties and has been widely used in a variety of applications, including as a catalyst in various types of reactions. In this work, chitosanbased solids were synthesized in order to obtain an active and stable material to be used as a catalyst in esterification reactions. To this end, the chitosan was modified in order to potentiate its Bronsted acidity by acid hydrolysis using HCl or H2SO4 solutions and subsequent drying in a vacuum line. The synthesized materials were characterized and evaluated in the esterification reaction of oleic acid with methanol. Although modification of chitosan with dilute solutions of inorganic acids is a simple method for the preparation of heterogeneous acid catalyst, there is evidence that the materials are not stable against the leaching of the active species into the reaction medium under the conditions evaluated.