Sonolysis organic solvents

In a non-aqueous medium, radicals other than OH can be generated. The sonolysis of organic solvents was thus studied by e.s.r. (p. 59). The decomposition of DPPH (2,2-diphenyl-l-picryl-hydrazyl) is a very sensitive probe of sonolysis of organic species, was used to determine a relative scale of the intensity of cavitation (p. 56). The decomposition of iron pentacarbonyl Fe(CO)5 cannot be used due to the toxicity of this molecule. The common drawback associated with chemical dosimeters is the dependence on frequency. Such standards should be considered as relative methods unable to provide an absolute value of energy. 

It is now clearly demonstrated through the use of free radical traps that all organic liquids will undergo cavitation and generate bond homolysis, if the ambient temperature is sufficiently low (i.e., in order to reduce the solvent system s vapor pressure) (89,90,161,162). The sonolysis of alkanes is quite similar to very high temperature pyrolysis, yielding the products expected (H2, CH4, 1-alkenes, and acetylene) from the well-understood Rice radical chain mechanism (89). Other recent reports compare the sonolysis and pyrolysis of biacetyl (which gives primarily acetone) (163) and the sonolysis and radiolysis of menthone (164). Nonaqueous chemistry can be complex, however, as in the tarry polymerization of several substituted benzenes (165). 

---