Acid-activated montmorillonites as heterogeneous catalysts for the esterification of lauric acid acid with methanol

A standard clay mineral was systematically subjected to activation with phosphoric acid under different concentrations and activation times. The materials were evaluated with regard to their structure, presence of functional groups, textural properties and the presence of Brِnsted and Lewis acid sites. After characterization, the best catalyst was evaluated in the esterification of lauric acid with methanol. High conversions were observed in short times (between 91.63 and 96.67%) and relatively mild reaction temperatures, revealing the potential of acid-activated clays as esterification catalysts for industrial applications such as biodiesel production. For comparison purposes, some experiments were also carried out with a standard solid acid catalyst (montmorillonite K10) and conversions of 95.03% were obtained in comparison to the best catalyst obtained in the present study (96.67%).