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Heterogeneous photocatayltic deperoxidation with UV and visible light
Author(s) -
Walalawela Niluksha,
Greer Alexander
Publication year - 2018
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3807
Subject(s) - chemistry , peroxide , photochemistry , radical , homolysis , fumed silica , hydrogen peroxide , acetophenone , adsorption , silica gel , organic peroxide , desorption , organic chemistry , catalysis , polymer , copolymer
A physical‐organic study is described on the photodecomposition of dicumyl peroxide co‐adsorbed with the sensitizers 4,4′‐dimethylbenzil or chlorin e 6 on fumed (nonporous) silica. Dicumyl peroxide was decomposed by the heterogeneous photosensitization and monitored by the desorption of products acetophenone, 2‐phenylpropan‐2‐ol, and α‐methylstyrene using proton nuclear magnetic resonance and gas chromatography‐mass spectrometry. Dicumyl peroxide and sensitizer were co‐adsorbed on silica in 1:4 up to 200:1 ratios, with high peroxide destabilization occurring in ratios of about 10:1. This increased photodecomposition corresponded to sensitizer‐peroxide distances of 6 to 9 Å. A Dexter triplet energy transfer mechanism is proposed that explains the short sensitizer and peroxide separation distances for higher peroxide OO bond homolysis efficiencies on silica. This biphasic (gas/solid) system can thus serve both to destabilize and stabilize a peroxide, which may be of practical use for the delivery of alkoxy radicals for bacterial disinfection.