PULSE-RADIOLYSIS OF BUTYL ACRYLATE IN AQUEOUS-SOLUTION

The pulse radiolysis of n-butyl acrylate (nBA) in aqueous solution was studied. The rate constant of the reaction of nBA with hydroxyl radic als was calculated as 1.5 x 10(10) dm(3) mol(-1) s(-1). The absorption spectrum of the OH.-nBA adduct appeared to have a broad maximum at 30 0 nm. This spectrum was attributed to the alpha-carbon.centred radical s. It decayed with the first-order rate constant k = 1.5 x 10(4) s(-1) (pH 10.8). The rate constant of the nBA reaction with hydrated electr ons was determined as k = 1.6 x 10(10) dm(3) mol(-1) s(-1). The spectr um of H-.-nBA adduct was similar to that recorded for OH. adduct. It d ecayed with first-order kinetics at k = 1.0 x 10(4) s(-1). Spectra of the electron adduct were characterised by the band with a maximum at 2 85 nm (pH 10.0) or at 280 nm (pH 4.0) with epsilon = 10 500 dm(3) mol( -1) cm(-1). In acidic solution, radical anion formed upon addition of hydrated electrons to the nBA molecule, undergoes fast, reversible pro tonation. The decay of the reversibly protonated electron adduct was a second-order process at k = 2.5 x 10(9) dm(3) mol(-1) s(-1). This rea ction took place at the carbonyl oxygen. Slow, irreversible protonatio n of the electron adduct at high pH takes place at the beta-carbon ato m at k = 2.9 x 10(4) s(-1). (C) 1998 Elsevier Science Ltd. All rights reserved.