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

The hydrated electron reaction with N-isopropylacrylamide (NIPA) has been s tudied in aqueous medium at different pHs using the nanosecond pulse radiol ysis technique. The rate constants for the initiation reaction of NIPA mono mer with hydrated electron (1.1 +/- 0.1 x 10(10) dm(3) mol(-1) s(-1)) acid hydroxyl radical (6.7 +/- 0.8 x 10(9) dm(3) mol(-1) s(-1)) were found to be diffusion controlled. The transients formed in the reaction of e(aq)(-) wi th NIPA were characterized by their spectral, kinetic and acid-base charact eristics. The results show that the transient decayed by good first order k inetics (k = 7.2 +/- 1.0 x 10(5) s(-1)) and the probable decay pathways hav e been discussed. The transients formed by H atom and CH2C(CH3)(2)OH radica l reactions with the monomer were also characterized by their absorption sp ectra. The H atom adduct of the monomer decayed by bimolecular kinetics wit h 2k/epsilon l value of 8 +/- x 10(5) s(-1) at its lambda(max) (410 nm). Ba sed on these observations, probable structures for the resultant transients have been suggested. (C) 2000 Elsevier Science Ltd. All rights reserved.