Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts

Aldol Condensation of Aldehydes and Ketones over Solid Base Catalysts

Introduction Industrially condensation reactions are of great importance in the production of a number of key compounds. These include 2-ethyl hexanol, methyl isobutyl ketone (MIBK) and Guerbet alcohols. Over 1.5 million tonnes of these chemicals are produced worldwide every year using homogeneous bases such as NaOH and Ca(OH)2. It has been estimated for these compounds that 30% of the selling ...

Selective Gas-Phase Conversion of Glycerol to Acetol Over Promoted Zirconia Solid Acid Catalysts

The vapour phase selective conversion of glycerol to acetol at normal atmospheric pressure in a fixed-bed micro reactor was investigated over SO4 2 and WOx promoted ZrO2 and M-ZrO2 (M = Al2O3 or TiO2) solid acid catalysts. The investigated sulfate and tungstate ion promoted zirconia-based catalysts were prepared by both coprecipitation and impregnation methods and calcined at 923 K. The synthes...

Nanoplatelet-based reconstructed hydrotalcites: towards more efficient solid base catalysts in aldol condensations.

Rehydration of Mg-Al hydrotalcite in the liquid phase using ultrasounds or a high stirring speed leads to nanoplatelets with surface areas of 400 m(2) g(-1), displaying catalytic activities in aldol condensations up to 8 times higher than the best catalytic system reported in the literature.

The Aldol Condensation Preparation of 4-Methoxybenzalacetone

The Complete Mechanism of an Aldol Condensation.

Although aldol condensation is one of the most important organic reactions, capable of forming new C-C bonds, its mechanism has never been fully established. We now conclude that the rate-limiting step in the base-catalyzed aldol condensation of benzaldehydes with acetophenones, to produce chalcones, is the final loss of hydroxide and formation of the C═C bond. This conclusion is based on a stu...