Reactions of N-isopropylacrylamide with some reducing and oxidising radicals in aqueous solutions: a pulse radiolysis study

Abstract

The hydrated electron reaction with N-isopropylacrylamide (NIPA) has been studied in aqueous medium at different pHs using the nanosecond pulse radiolysis technique. The rate constants for the initiation reaction of NIPA monomer with hydrated electron (1.1 ± 0.1 × 10 10 dm 3 mol −1 s −1) and hydroxyl radical (6.7 ± 0.8 × 10 9 dm 3 mol −1 s −1) were found to be diffusion controlled. The transients formed in the reaction of e aq − with NIPA were characterized by their spectral, kinetic and acid–base characteristics. The results show that the transient decayed by good first order kinetics ( k = 7.2 ± 1.0 × 10 5 s −1) and the probable decay pathways have been discussed. The transients formed by H atom and CH 2C(CH 3) 2OH radical reactions with the monomer were also characterized by their absorption spectra. The H atom adduct of the monomer decayed by bimolecular kinetics with 2 k/ εl value of 8 ± 1 × 10 5 s −1 at its λ max (410 nm). Based on these observations, probable structures for the resultant transients have been suggested.