Resumen de Fotomalogenacio d'acids alcanoics fixats sobre diversos suports polimerics
Photochemical halogenation of acyl moieties in methyl octaoate benzyl octanoate2-phenylethyl octanoate are studied and compared with photohalogenation of 2-(poly-p-styryl)-ethyl octanoate and poly-p-styryl)methyl octanoate. In the chlorinations the methylene hydrogens at c2 are strongly deactivated due to the inductive effect of the carbonyl group. On the other hand the hydrogens at cw are less reactive than other methylene hydrogens wile maximum reactivity is found in cw-1 probably due to the greater inductive effect of the me group and/or hyperconjugation. On solid phase photochlorination enhanced selectivity is found for cw-1 which can be explained by a complex- between electrophyllic chlorine radicals and aromatic nucleui. Bromination of these substrates shows greater reactivity at c2 due to the mesomeric effect of the carbonyl group. No bromination takes place at cw due to the minor reactivity of methyl groups together with the great selectivity of bromine atoms. In solid phase al most no bromination is observed probably due to the selectivity of bromine atom for the benzilic positions.
