Glycerol etherification with benzyl alcohol over sulfated zirconia catalysts

Abstract

Glycerol (GLY) etherification with benzyl alcohol (BA) was conducted with different zirconia-based heterogeneous acid catalysts, aiming to produce mono- (ME) and dibenzyl glycerol ethers (DE). Physicochemical properties of the prepared catalysts were obtained through XRD, SEM and adsorption of ammonia. The catalytic tests were performed at different temperatures (120-140°C) and initial reactant mass ratios (GLY:BA 1:1 and 2:1). The highest BA conversions were obtained with the catalyst having the highest sulfuric acid content (2S/ZrO2). An increase in the reaction temperature and the GLY:BA initial mass ratio led to an increase in the BA conversion. Two kinetic models (a potential and a hyperbolic approach) were proposed to describe the process performance, including not only reactants evolution with time, but also that of ME, DE and the undesired self-condensation product of BA (benzyl ether, BE). Kinetic parameters for each model were estimated by data fitting and both models were able to accurately describe the evolution of the system, in terms of reactants and product distribution as a function of time under the experimental conditions studied.