The intensity of ultrasound is attenuated due to various properties of the liquid, such as viscosity, density, etc. In this paper, a simple method is proposed to measure the combined attenuation and cavitational activity of ultrasound intensity in various organic liquids using standard KI decomposition reaction. A modified experimental attenuation coefficient is proposed and its dependence on liquid viscosity reasonably matches the theoretical predictions made by Stokes [G.G. Stokes, Trans. Camb. Philos. Soc. 8 (1849) 287]. Exploratory work to determine the effect of other liquid properties on cavitational activity is carried out. Correlations are proposed to explain the dependence of the attenuated cavitational activity on various properties of a liquid.

In the present work hydrolysis of methyl benzoate was carried out using aqueous sodium hydroxide solution at room temperature in the presence of ultrasound since otherwise the same reaction takes place at relatively high temperature. Also, the above hydrolysis reaction was investigated at a relatively larger scale with the variation in parameters influencing the emulsification process and hence the reaction rates. It has been observed that the position of ultrasound source on the liquid-liquid interface is a crucial parameter affecting the two-phase emulsification rates. The poor bulk mixing occurring in the presence of ultrasound alone with an increase in the volume of the reaction mixture and its consequent effect on the reaction kinetics has been conclusively established. These studies have shown that the use of ultrasound with mechanical stirring can result in substantial reduction in the overall power consumption, especially for reaction systems like hydrolysis that do not require very high temperatures and pressures generated by cavitation.