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SINGLET OXYGEN REACTIONS WITH 2,7‐DIMETHYL‐2,6‐OCTADIENE
Author(s) -
Tanielian Charles,
Chaineaux Jacques
Publication year - 1978
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1978.tb06956.x
Subject(s) - singlet oxygen , rose bengal , double bond , chemistry , conjugated system , reactivity (psychology) , photochemistry , diene , singlet state , polymerization , reaction rate constant , molecule , oxygen , computational chemistry , medicinal chemistry , organic chemistry , kinetics , excited state , polymer , physics , atomic physics , medicine , natural rubber , alternative medicine , pathology , quantum mechanics
— Results concerning Rose Bengal sensitized photoxidation of 2,7‐dimethyl‐2,6‐octadiene (A) are discussed. This diolefin may be considered as a model molecule of polyisoprene of polymerization number two with 1,4‐4,1 addition mode. All the mono‐ and dihydroperoxides apt to occur are actually obtained. One of the occurring hydroperoxides, 2,7‐dimethyl‐dihydroperoxy‐3,5‐octadiene, which has the structure of a conjugated diene, does not lead to an endoperoxide. This is contrary to Kaplan and Kelleher's hypothesis. On the other hand, no trihydroperoxide forms as a result of further addition of singlet oxygen ( 1 O 2 ). A complete kinetic study has allowed us to determine the rate constants of all the reactions which take place. The reactivity of (A) is twice that of 2‐methyl‐2‐pentene and the addition of 1 O 2 to one of the double bonds of (A) induces deactivation of the remaining double bond.