Sonolysis of tert-butyl alcohol in aqueous solution

A product study of the sonolysis of the volatile substrate t-butanol in aqu eous solution indicates that substrate decomposition is practically complet ely determined, even at concentrations as low as millimolar, by oxidative p yrolysis going on in the gas phase within the collapsing cavitational bubbl e. OH-Radical-induced reactions in solution are insignificant since the vol atility of this substrate, its gas-phase concentration within the bubble en hanced by a certain degree of hydrophobicity, causes OH radicals generated thermolytically from water vapour to be intercepted before they can reach t he aqueous phase. The nature of the products, as well as the t-butanol-conc entration dependence of the product yields, can be qualitatively explained- on the basis of the t-butanol-pyrolysis mechanism. Kinetic considerations i nvolving the relative yields of the pyrolysis products ethane, ethylene and acetylene lead to an estimate of a value of 3600 K for the average pyrolys is temperature at a t-butanol bulk concentration of 10(-3) molar.