Metal complexes as antioxidants. III. Reaction of nickel dialkyldithiocarbamates and nickel dialkyldithiophosphates with alkyl hydroperoxides

Autor:	J. H. B. Chenier, J. A. Howard
Rok vydání:	1976
Předmět:	chemistry.chemical_classification Autoxidation Chemistry Radical Organic Chemistry chemistry.chemical_element General Chemistry Photochemistry Decomposition Catalysis Metal chemistry.chemical_compound Nickel Cumene hydroperoxide visual_art visual_art.visual_art_medium Alkyl Acetophenone
Zdroj:	Canadian Journal of Chemistry. 54:390-401
ISSN:	1480-3291 0008-4042
DOI:	10.1139/v76-053
Popis:	Alkyl hydroperoxides are shown to react with nickel dialkyldithiocarbamates and nickel dialkyldithiophosphates in the liquid-phase at 30 °C to generate free radicals. These radicals are capable of inducing the decomposition of the hydroperoxide and destroying the nickel complex. Rates of radical generation, as determined from hydrocarbon autoxidation, are similar to rates of complex disappearance and are ca. 1/5th rates of hydroperoxide disappearance. Rates of disappearance of both reactants are retarded by the addition of hydrogen atom donating antioxidants, the rate of hydroperoxide disappearance is reduced to the rate of radical generation and the rate of complex disappearance is significantly less than the rate of radical generation. These results are consistent with a mechanism for decomposition which involves cycling of the nickel complex. Decomposition of cumene hydroperoxide to α-cumyl alcohol, α-methylstyrene and acetophenone suggests the intermediacy of cumyloxy radicals in this system while the electron spin resonance spectroscopic method indicates that alkylperoxy radicals are also transient intermediates.
Databáze:	OpenAIRE
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