THE SYNTHESIS OF ESTERS UNDER MICROWAVE IRRADIATION USING DRY-MEDIA CONDITIONS

Practical and simple techniques are described for using nonmodified domestic microwave ovens as safe and convenient laboratory devices to obtain numerous esters. High pressures are avoided by conducting reactions with reactants impregnated on solid mineral supports in ''dry media'' or by phase transfer catalysis (PTC) in the absence of organic solvents. Two kinds of microwave effects are involved: (1) displacement of the equilibrium by evaporation of volatile polar molecules (water or alcohols) in esterifications and transesterifications; (2) acceleration of ionic reactions in carboxylate alkylations. As solvents are avoided, there is no need for sealed vessels and water separators.