pH dependent hydrolysis of 2-hydroxypropyl methanethiolsulfonate

Article abstract of DOI:10.1021/jf950722n

The hydrolysis of 2-hydroxypropyl methanethiolsulfonate (HPMTS), an industrial water treatment microbicide, was investigated at 25°C and at three pH values (pH 5, 7, and 9). Radiolabeled (¹⁴C) HPMTS at a concentration of 100 mg/L was used to determine rate constants and to identify hydrolytic degradation products. The hydrolysis at all three pHs followed pseudo-first-order kinetics with rate constants of 5.8 × 10^-4, 7.6 × 10^-2, and 7.3. h^-1 at pH 5, 7, and 9, respectively. Two major radiolabeled hydrolytic degradation products were observed at all three pH values and were identified to be bis(2-hydroxyisopropyl) disulfide and bis(2-hydroxypropyl) disulfide by particle beam LC/MS. On the basis of the observed degradation products, a hydrolytic degradation pathway for HPMTS using propylene epoxide as a reactive intermediate was postulated.