Acrolein production by oxidative coupling of alcohols over zinc and cobalt aluminate spinels enlightened by adsorption calorimetry study

Abstract

This work reports on the production of acrolein by oxidative coupling of biosourced alcohols (methanol and ethanol). This reaction is performed in a two-step process using iron molybdate catalyst to produce formaldehyde and acetaldehyde and zinc and cobalt aluminate spinels, with or without vacancies, to perform the cross-aldolization of aldehydes. In this study, adsorption microcalorimetry of NH3 and SO2 was used to determine the acid-base properties of the catalysts. The catalytic activity was monitored and correlated to catalysts acid-base properties. Moreover, to enlighten the behavior of reactants over the surface and the mechanism of the reaction, an extensive adsorption microcalorimetric study using acetaldehyde and formaldehyde as probe molecules was performed to determine molar enthalpies, molar entropies, thermokinetic parameters but also energy spectra. This broad calorimetric study provided a better understanding of the reaction and allowed to confirm the preferential adsorption of formaldehyde compared to acetaldehyde thus justifying the absence of crotonaldehyde in the products of the catalytic reaction.