Phosphororganische Antioxidantien. III. Kinetik und Mechanismus der Cumylhydroperoxidzersetzung durch cyclische Phosphite

Abstract

Organophosphorus Antioxidants. III. Kinetics and Mechanism of the Decomposition of Cumyl Hydroperoxide by Cyclic Phosphites The reaction mechanism of cyclic esters of phosphorous acids I to VIII with cumyl hydroperoxide has been studied kinetically by means of 31P n.m.r. spectroscopy, high performance liquid chromatography and iodometric titration. The five‐membered cyclic phosphites (I and II) react with cumyl hydroperoxide to give the corresponding phosphates (AI and AII) and cumyl alcohol. With more hydroperoxide or water they form the open chain phosphate esters (BI and BII) which decompose cumyl hydroperoxide catalytically giving phenol and acetone. Higher membered cyclic phosphites (III to VIII) react with cumyl hydroperoxide to give the corresponding phosphates and alcohol only. The mode of reaction depends on the hydrolysis behaviour of the cyclic phosphates (AI to A VIII). Only fivemembered cyclic phosphites which give easily hydrolyzable phosphates are able to decompose cumyl hydroperoxide catalytically. The nature of the exocyclic group in the phosphites has no influence on this behaviour. The kinetic parameters of the separate reaction steps are given. The ionic mechanism of hydroperoxide decomposition is accompanied by a homolytic one.

Synthesis, characterization, and application of oligomer‐type‐based phosphites

“…Generally, oxidation of phosphites is strongly dependent on alkyl substitution. To understand the chemistry of these antioxidant properties, Rüger et al extensively examined model studies of the decomposition of cumene hydroperoxide caused by phosphorous acid esters . The results of the hydroperoxide decomposition by phosphites were summarized by Schwetlick et al , and the order of reactivity reveals that phosphonites and aliphatic phosphites react more rapidly than aromatic phosphites.…”

Synthesis, characterization, and application of a hydrolytically stable liquid phosphite

“…To understand the chemistry of these antioxidant properties, Rüger et al extensively examined model studies of the decomposition of cumene hydroperoxide caused by phosphorous acid esters . The results of the hydroperoxide decomposition by phosphites were summarized by Schwetlick , and the order of reactivity reveals that phosphonites and aliphatic phosphites react more rapidly than aromatic phosphites.…”