Res. Chem. Intermed.
, Vol. 30, No. 7-8, pp. 683–684 (2004)
Also available online - www.vsppub.com
Sonochemistry, a developing scientiﬁc ﬁeld, offers a wide range of applications in
chemistry, physics, medicine and food science. Sonochemical reactions are caused
by ultrasound-generated ‘cavitation’ bubbles in a liquid medium. These cavitation
bubbles are also referred to as ‘Hot Spots’, owing to the extreme temperature
conditions generated within these bubbles on collapse. While cavitation can also
cause physical effects, such as, ‘microstreaming’, microjetting, turbulence, etc.,
which can also enhance reaction efﬁciencies, the vast majority of chemical reactions
are induced by primary radicals generated within cavitation bubbles.
The articles presented in this Special Issue primarily deal with ‘Aqueous Sono-
chemistry’, i.e. sonochemical reactions in aqueous medium, where the primary rad-
, are generated by the homolysis of water within the collapsing
bubbles. An interesting aspect in aqueous sonochemistry is that both oxidizing and
reducing radicals are generated, that can be used for many chemical reactions, rang-
ing from the synthesis of nanoparticles to the synthesis of macromolecules. Organic
sonochemistry has also been included to highlight the fact that sonochemical reac-
tions can be carried out in any liquid medium.
The high-quality articles presented in this Special Issue of Research on Chemical
Intermediates have been contributed by several leading international sonochemistry
research groups. These contributions include, on the applications side, the investiga-
tion of radical intermediates in polymer sonochemistry, synthesis of nanoparticles,
sonochemical reactions in organic solvents and the degradation of chemical pollu-
tants. While half of the contributions deal with the applications of sonochemistry,
understanding the fundamental aspects of sonochemistry is crucial in achieving
maximum reaction efﬁciency. This aspect is particularly important if these sono-
chemical reactions are to be commercialized. In this respect, the other half of the
contributions in this issue deal with the fundamental aspects of sonochemistry, such
as, the effect of frequency, the combination of photochemistry and sonochemistry,
spatial distribution of bubble ﬁelds and comparison between the yields of primary
radicals and other sonochemical reactions.