Cavitation advantage

The choice of the solvent also has a profound influence on the observed sonochemistry. The effect of vapor pressure has already been mentioned. Other Hquid properties, such as surface tension and viscosity, wiU alter the threshold of cavitation, but this is generaUy a minor concern. The chemical reactivity of the solvent is often much more important. No solvent is inert under the high temperature conditions of cavitation (50). One may minimize this problem, however, by using robust solvents that have low vapor pressures so as to minimize their concentration in the vapor phase of the cavitation event. Alternatively, one may wish to take advantage of such secondary reactions, for example, by using halocarbons for sonochemical halogenations. With ultrasonic irradiations in water, the observed aqueous sonochemistry is dominated by secondary reactions of OH- and H- formed from the sonolysis of water vapor in the cavitation zone (51—53). 

Vibratory test apparatuses are relatively cheap to build and run, and have low power consumption, while flow rigs are bulky, expensive to build and run, and have high power consumptions but have the advantage that they simulate more closely practical conditions of hydrodynamic cavitation. On the other hand, the damage rate is higher in the vibratory tests than in the... 

Solonitsyn RA, Fumbarov AG, Tomashchuk GL, Grinin TV (1987) Advantages of Cavitation Method for Activation of Waste Paper. Bum Prom-St 1 25-27... 

The chemical applications of ultrasound (Sonochemistry) have become an exciting new field of research during the past decade. Recently, Li and coworkers have found an efficient and convenient procedure for the preparation of oximes via the condensation of aldehydes and ketones in ethanol with hydroxylamine hydrochloride under ultrasound irradiation (Scheme 8). Compared with conventional methods, the main advantages of the sonochemical procedure are milder conditions, higher yields and shorter reaction periods. The reason may be the phenomenon of cavitations produced by ultrasound. 

One of the advantages of cavitational synthesis, providing the synthesis equipment has the capability to adjust the bubble dynamics, is the capability to do synthesis under the conditions of both high shear and in situ calcination. If the equipment can be adjusted to operate in slightly different fluid dynamic regimes, it should be possible to obtain both high-phase purity catalysts and to systematically adjust the primary grain size of the crystallites... 

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