ABSTRACT
The influence of ultrasonic energy on chemical activity may involve any or all of the following: production of heat, promotion of mixing, promotion of intimate contact between materials, dispersion of contaminated layers of chemicals, and production of free chemical radicals. The fundamental physical-chemistry concepts behind ultrasonic cavitation and sonochemistry have become increasingly well understood and documented. Emulsification by ultrasound also enhances chemical reaction between the components of the emulsion by a dramatic increase in interfacial contact area between the liquids involved. Efficient mixing of heterogeneous reaction mixtures certainly is an important contribution of ultrasonic irradiation. The acceleration of certain chemical reactions by the application of an ultrasonic field can occur by direct agitation and/or new reaction intermediates. Throughout the history of ultrasonics, many interesting chemical reactions have been stimulated or accelerated under the influence of high-intensity ultrasonic energy, particularly under the influence of cavitation.
