Application of the spin trapping technique to radical polymerization, 19. Reactions of the tert‐butoxyl radical with some N‐alkyl‐substituted acryl‐ and methacrylamides

Abstract

AbstractThe reactions of tert‐butoxyl radical with some N‐alkyl‐substituted acryl‐ and methacrylamides were investigated at room temperature in benzene by means of the spin trapping technique. 2‐Methyl‐2‐nitrosopropane (BNO) was used as a spin trapping reagent. The tert‐butoxyl radical was found to undergo both hydrogen‐abstraction from N‐methyl groups and double bond addition in its reactions with N‐methylacrylamide (NMAm) and with N,N‐dimethylacrylamide. Contrary to this, the benzoylthio radical reacted exclusively with the double bond of NMAm. In the reaction of the tert‐butoxyl radical with N‐methylmethacrylamide (NMMAm), only double bond addition was observed. However, when the tert‐butoxyl radical reacted with N,N‐dimethylmethacrylamide (NDMMAm), it mainly attacked the N‐methyl group of NDMMAm. The tert‐butyl radical abstracted a hydrogen atom from the α‐methyl group of NMMAm and NDMMAm, keeping their N‐methyl group unreacted. Furthermore, in the reaction of the tert‐butoxyl radical with N‐propyldimethacryloylamine (NPDMAm) in the presence of BNO, both a methylene radical which was derived from intramolecular cyclopropagation giving a five‐membered ring and a radical derived from the addition to the double bond of NPDMAm were trapped as their aminyl radicals.