Last Decade of Research in Sonochemistry for Green Organic Synthesis

Abstract

Ultrasounds, an efficient and virtually innocuous means of activation in synthetic chemistry, have been employed for decades with varied success. This high-energy input enhances not only mechanical effects in heterogeneous processes, but it is also known to induce new reactivities leading to the formation of unexpected chemical species. The remarkable phenomenon of cavitation makes sonochemistry unique. This patent review is aimed at summarizing the status of cavitational chemistry in organic synthesis and to highlight the more recent applications in this field. The use of ultrasound to promote chemical reactions is called sonochemistry. The effects of ultrasound observed during organic reactions are due to cavitation, a physical process that creates, enlarges, and implodes gaseous and vaporous cavities in an irradiated liquid. Cavitation induces very high local temperatures and pressures inside the bubbles (cavities), leading to turbulent flow of the liquid and enhanced mass transfer. Keywords: Ultrasounds, cavitation, heterogeneous catalysis, photocatalysis, phase transfer catalysis, aqueous media, ionic liquids, acid-catalyzed reactions, base-catalyzed reactions, C-C bond formation, oxidation reactions, reduction reactions