A Facile Tandem Protocol for the Crossed Aldol Condensation in SiO2.OSO3H Ionic Liquid under Solventless Condition

Abstract

Objectives: Removing organic solvents in chemical synthesis is important in the drive towards benign chemical technologies. Organic solvents are high on the list of toxic compounds due to the problems in containing volatile compounds and the sheer large volume of them used in industry. Some advantages of utilizing solventless reactions are that the compounds are often sufficiently pure to avoid extensive purification using chromatography, the reactions can be rapid, and often reaching substantial completion in several minutes compared to hours in organic solvents, and the energy usage can be much lower. Among organic reactions, aldol condensations are important and excellent tools in organic synthesis, providing a good way to form carbon–carbon bonds. The main objectives of this paper are to carryout crossed - aldol condensation reactions with dicyclohexylketones with different aromatics aldehydes in the presence of silica sulphuric acid [SiO2.OSO3H] as an ionic liquid catalyst under solvent free condition to afford the corresponding α, β - unsaturated crossed - aldol products in excellent yields and to recover and reuse the catalyst for subsequent use. Study design: Green chemical reaction using silica-sulphuric acid as a catalyst under solventless condition.