Phosphororganische Antioxidatien. X [1]. Über die hydroperoxidzersetzende Wirkung von Phosphiten, Phosphoniten und Thiophosphiten

Abstract

Organophosphorus Antioxidants. X. The Hydroperoxide Decomposing Action of Phosphites, Phosphonites and Thiophosphites The kinetics and mechanism of reactions of phosphites, phosphonites, thiophosphites and hydrogenphosphites with cumyl (CHP), t‐butyl (TBHP) and α‐tetralyl (THP) hydrogenperoxides has been studied by means of 31P‐n.m.r. spectroscopy, high performance liquid chromatography and iodometric titration. All three valent phosphorus compounds studied initially react with hydroperoxides stoichiometrically to give the corresponding PO products and alcohol. Some species are able to decompose cumyl hydroperoxide catalytically to form phenol and aceton. Acyloin phosphites decompose CHP catalytically after a stoichiometric reaction as thiophosphites do. Tetramethylpiperidinyl phosphites (“HALS‐phosphites”) react with hydroperoxides only stoichiometrically but with high velocity. Phosphonites react with hydroperoxides in the same way as the corresponding phosphites. Their reactivity, however, is much higher. Hydrogenphosphites are less reactive than phosphites in the reaction with hydroperoxides. They are able to act catalytically.