Effect of catalyst morphology and hydrogen co-feeding on the acid-catalysed transformation of acetone into mesitylene

Abstract

Surface chemistry and pore topology affect mesitylene selectivity in acid-catalysed acetone condensation. Hydrogen improves both catalyst stability and condensation selectivity.

One-Pot Conversion of Acetone into Mesitylene over Combinations of Acid and Basic Catalysts

“…Thus, temperature appears to be a key parameter to control the evolution of both pathways. The previous literature confirms by diffuse reflectance infrared Fourier transform spectroscopy the strong adsorption of both compounds on an acid surface and the presence of oligomers derived from acetic acid, a consequence of the high interaction of the metal cations of the catalytic surface (Lewis sites) and the carboxylic functional group. ,, …”

“…Comparing these results with those obtained using β-zeolite, the relevance of the position of each site on the catalytic surface is also suggested. The molecular size of mesitylene is higher than the voids of this zeolite (8.7 and 6.7 Å, respectively) . The positive trend of its conversion reveals that its formation happens on the external acid sites, and these sites are not affected by the deactivation.…”

“…On the other hand, acid materials such as microporous and mesoporous aluminosilicates have been also proposed, catalyzing the acetone condensation by Brønsted or Lewis acidic sites (i.e., protons or metal cations, respectively) and promoting the mesitylene production (E 2 mechanism). − However, this acidity also promotes the mesityl oxide cracking by β-scission, indicated with a dashed line in the scheme, a non-desired reaction that produces isobutene and acetic acid and, to a lesser extent, other light alkenes . This reaction strongly limits their application since acetates and their oligomers are involved in the catalytic deactivation by solid deposition. , …”

Selective conversion of acetone to mesitylene over tantalum phosphate catalysts

“…Acetone can be transformed into products with higher molecular weights by acid or base catalysts. 14–20 Typically, basic catalysts can catalyze the production of phorone 17 and acid catalysts can catalyze the production of mesitylene. 14 Both products are nine carbon-containing products.…”

“…21 Various catalysts such as hydrotalcite, mixed metal oxides, Nb 2 O 5 , and zeolites are active for the conversion of acetone to mesitylene. 14–20 However, the mesitylene yield over these catalysts is normally less than 60%, which is a great challenge for the practical conversion of acetone to biofuels.…”