Aquasonolysis of thioethers

The aquasonolytical rate constants and products of diethyl sulfide, diallyl sulfide, dipropyl sulfide, dibutyl sulfide, diethyl disulfide, and dipropyl disulfide have been investigated. The sonolysis for model compounds in aqueous solutions follows the pseudo-first-order kinetics. Disulfides are more rapidly sonicated than sulfides. Neither vapour pressure nor thermostability of thioethers can obviously affect their aquasonolytical rates. Higher Henry's Law constant and hydrophobicity of substrate result in a higher aquasonolytical rate constant. Furthermore,. the aquasonolytical rate constant decreases as the initial concentration of dipropyl sulfide increases. CS2, COS, thiols, thiirane, lower sulfides, butenyne, and butadiene are detected as principal very volatile products during ultrasonic irradiations. Thiophene, benzene, 1,5-hexadiene, and cyclopentadiene are additionally obtained during the aquasonolysis of diallyl sulfide. Furthermore, trisulfides, trithiolane, and other cyclic thiolanes as volatile products are observed. These results demonstrate that thioethers undergo thermal decomposition during their aquasonolyses. The transfer process of volatile thioethers between cavitation bubbles and bulk liquid remarkably affect the aquasonolysis, and the hydrophobicity of substrate dominates the transfer process. (C) 2005 Elsevier B.V. All rights reserved.