Solid–catalyzed esterification reaction of long–chain acids and alcohols in fixed–bed reactors at pilot plant scale

Abstract

The esterification reaction of long–chain acids and alcohols is carried out in both academia and industry with soluble strong acids such as phosphoric or methanesulfonic acid, since the lower diffusion and higher steric hindrance of the long–chain reactants compared to small derivatives (such as methanol or ethanol) severely hampers a smooth esterification on catalytic solids. In order to design an efficient industrial process for the esterification reaction of long–chain acids and alcohols, under flow conditions, solid catalysts are of interest. Here we show that the esterification of different fatty acids with 2–ethyl hexyl alcohol proceeds in very high yields and selectivity when carried out with organic solid acids both in batch and in flow processes, enabling the use of fixed–bed reactors to perform the esterification reaction. To evaluate the process under real industrial conditions, experiments at multi–kilogram scale in pilot plant tubular reactors were carried out, confirming the feasibility of the ton–scale production of long–chain esters over solid catalysts in a continuous process.