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Chemiluminescent autoxidation of linolenic acid films on silica gel
Author(s) -
Slawson Vida,
Adamson Arthur W.
Publication year - 1976
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02532838
Subject(s) - autoxidation , monolayer , chemistry , singlet oxygen , photochemistry , chemiluminescence , quantum yield , induction period , analytical chemistry (journal) , excited state , emission spectrum , yield (engineering) , reaction rate constant , phase (matter) , oxygen , organic chemistry , spectral line , materials science , kinetics , catalysis , fluorescence , optics , atomic physics , biochemistry , physics , astronomy , metallurgy , quantum mechanics
Abstract Films of linolenic acid supported on chromatographic type silica gel undergo autoxidation at a rate which is slow compared to that in homogeneous phase at low surface coverage but comparable to it at coverages approximating a close‐packed monolayer. The new observation reported here is that these surface phase oxidations are chemiluminescent. The quantum yield is ca. 10 −12 quanta per molecule of fatty acid reacted for a close‐packed monolayer and remains approximately constant with decreasing coverage. The emission intensity is temperature dependent, with an apparent activation energy of 10 kcal mol −1 , and shows an induction period for close‐packed monolayers. The emission spectrum contains a component consistent with excited state ketone emission and a low energy component, ca. 600+ nm, which could be due to singlet oxygen emission. The existence of the emission means that surface autoxidation reactions can be followed in place; the nature of the emission may provide insight into the autoxidation mechanism beyond that which may be inferred from conventional rate measurements.