Aldol Condensation of Cyclopentanone with Valeraldehyde Over Metal Oxides

Abstract

Kinetics of the cross aldol condensation of valeraldehyde with cyclopentanone was investigated in a batch reactor under atmospheric pressure at 130 °C using heterogeneous metal modified oxides, such as CeO 2 -MgO, FeO-MgO, FeO-CaO as well as pristine CaO as catalysts. The catalysts were prepared either by evaporation impregnation or deposition precipitation methods and characterized by XRD, TEM, SEM, nitrogen adsorption, ammonia and CO 2 TPD. The results revealed that an optimum amount of strong basic sites gives the highest ratio between cross condensation and self-condensation products of valeraldehyde. The highest yield of the desired product 2-pentylidenecyclopentanone (66%) was obtained with FeO-MgO prepared by the deposition precipitation methods. Graphical AbstractCross-condensation of valeraldehyde with cyclopentanone was investigated over heterogeneous Fe-CaO, CeO-MgO, FeO-CaO and CaO catalysts at 130 °C using cyclopentanone as a solvent and reactant. The highest yield of the desired product, 2-pentylidene-cyclopentanone, finding applications as fragrances, flavours and pharmaceuticals, was 66% obtained over FeO-MgO catalyst exhibiting both acid and basic sites.

One-pot synthesis of 2-alkyl cycloketones on bifunctional Pd/ZrO2 catalyst

“…For the bifunctional catalyst, support is as important as metals, which provides the acid-base sites for aldol condensation [1]. Therefore, in order to understand the effect of supports, commonly used supports, such as acidic Al 2 O 3 [38], strong basic MgO, CaO [39,40] and weak basic ZnO [41], TiO 2 [42], CeO 2 [43] [36] cooperatively resulted in the high performance of Pd/ZrO 2 catalyst.…”

Gas‐Phase Hydroformylation Using Supported Ionic Liquid Phase (SILP) Catalysts – Influence of Support Texture on Effective Kinetics

“…For hydroformylation of e. g. but‐1‐ene, the formed C 5 aldehydes n ‐ and iso ‐pentanal constitute a challenge for long‐term Rh‐SILP catalysis since they are prone to undergo aldol condensation (see Scheme 1). [28,29] The as formed C 10 aldols, having a low vapor pressure, tend to accumulate inside the ionic liquid film and inevitably lead to swelling and pore blocking [30] . Such effects result in lowered catalytic activities with time, making the industrial application difficult, if catalyst regeneration scenarios via e. g. pressure swing have to be implemented.…”

Recent Advances in the Catalytic Production of Platform Chemicals from Holocellulosic Biomass

“…Lignocellulosic matter is primarily constituted by cellulose, hemicellulose and lignin. [10][11][12][13][14][15][16][17][18][19] Holocellulose considers cellulose and hemicellulose (the carbohydrate part of lignocellulose). Hemicellulose is formed by pentoses (xylose, arabinose and ribose) and hexoses (glucose, fructose, galactose and mannose), of which xylose, a monomer of xylan, is the most common component.…”