ESR STUDY OF FREE-RADICAL DECOMPOSITION OF N,N-BIS(ARYLSULFONYL) HYDROXYLAMINES IN ORGANIC SOLUTION

Decomposition of N,N-bis(p-tolylsulfonyl)hydroxylamine (BTH) in chloro form and benzene solutions has been studied and was found to involve t he formation of several radical intermediates. This process has been f ound to be accelerated by oxygen, resulting in the formation of p-tolu enesulfonic acid and N,N,O-tris(p-tolylsulfonyl)hydroxylamine (TTH) as the main decay products. In addition, a small amount of p-toluenesulf onyl chloride has been isolated from chloroform solution, suggesting t he chlorine abstraction from solvent. The formation of nitric oxide (N O) from BTH has been shown by mass spectrometry in gaseous phase and u sing nitronyl nitroxide as an NO trap in solution. It was proposed tha t Liberation of NO proceeds through the homolytic cleavage of the S-N bond of p-tolylsulfonyl nitrite existing in equilibrium with BTH in so lution. The formation of p-tolylsulfonyl radicals has been proved by s pin trapping using 2-methyl-2-nitrosopropane (MNP) and 5,5-dimethyl-1- pyrroline N-oxide (DMPO). The rate of NO production in the presence of nitronyl nitroxide and the rate of oxygen consumption revealed linear plots in BTH concentration with the rate constants 0.0044 s(-1) and 0 .0016 s(-1), respectively. It was found also that nitrogen dioxide for med during NO oxidation reacts readily with BTH to produce the organic analog of Fremy's radical. This radical recombines with p-tolylsulfon yl radical yielding N,N,O-trisubstituted hydroxylamine TTH.