The rapid synthesis of organic compounds in microwave ovens

Abstract

This work demonstrates that organic compounds can be synthesized up to 1240 times faster in sealed Teflon vessels in a microwave oven than by conventional (reflux) techniques. It is shown that all polar molecules absorb microwave energy rapidly and that the rate of energy absorption varies with the dielectric constant. The rates of reaction of polar molecules in nonpolar solvents are not increased appreciably by the microwave method. Also, the homogeneity of the reaction does not affect the rate enhancement. The rate enhancement arises predominantly because the oven superheats the solvent rapidly. Finally, pressure (temperature) measurements have shown that the maximum rate enhancement is achieved when the proper power level and volume of solvent are used. It appears that rate enhancements of approximately 200 are possible for many reactions if the reaction conditions are optimized.