RADICAL SCAVENGING IN THE SONOLYSIS OF AQUEOUS-SOLUTIONS OF I-, BR-, AND N3-

Iodide and bromide solutions are sonolyzed under pH conditions, where reactions of the products, i.e. hydrogen peroxide and iodine (or bromine), do not occur. The total yield of the products as well as the hydrogen yield is independent of solute concentration. The results are understood in terms of the competition of the OH + OH and the OH + solute reactions. A local concentration of 4 x 10(-3) M of the OH radicals in an interfacial region between the cavitation bubbles and the liquid is derived from the data obtained. The sonolysis of azide solutions is also investigated. The main product is nitrogen, which is formed in the reaction of N3- with OH radicals in the millimolar concentration range. At higher azide concentrations, additional nitrogen is formed as hydrogen atoms are also scavenged. Ammonia and hydrazine are minor products of the N3- sonolysis.