The study represents the product distribution observed for the different active sites present in the tested catalysts, showing significant limitations in the case of the stronger sites, with limited selectivity to mesitylene and suffering severe deactivation. In contrast, the weak centers favor mesitylene formation and showed higher stability.

Abstract

Acetone is a promising platform molecule for renewable processes, as it can be obtained from biomass via fermentation or pyrolysis. In the presence of acid or base catalysts, acetone condenses and dehydrates, leading to the formation of mesitylene. A sustainable production process using renewable sources is needed to meet the demand for mesitylene, a compound with applications in the chemical and pharmaceutical industries, as well as in aviation fuel additive. The work explores the potential of Ti and Al phosphates as acid catalysts for the gas-phase self-condensation of acetone to mesitylene. These materials were synthesized by simple one-pot evaporation induced self-assembly method and precipitation. The Ti phosphate was modified with K and Si to tailor acid-sites distribution. Catalytic activity and stability were studied in a fixed-bed continuous reactor at 225 °C, space velocity of 1900 mol/(kg h)) and a feed of 15% acetone in nitrogen. Fresh and used catalysts were characterized to determine the structure–reactivity relationships. In this context, the presence of mild and strong Brønsted acid sites was correlated to a higher deactivation by strong adsorption of high-molecular-weight condensation products.