Radical and Atom Transfer Halogenation (RATH): A Facile Route for Chemical and Polymer Functionalization

Abstract

This work demonstrates a new halogenation reaction through sequential radical and halogen transfer reactions, named as "radical and atom transfer halogenation" (RATH). Both benzoxazine compounds and poly(2,6-dimethyl-1,4-phenylene oxide) have been demonstrated as active species for RATH. Consequently, the halogenated compound becomes an active initiator of atom transfer radical polymerization. Combination of RATH and sequential ATRP provides an convenient and effective approach to prepare reactive and crosslinkable polymers. The RATH reaction opens a new window both to chemical synthesis and molecular design and preparation of polymeric materials.

2,2,6,6‐Tetramethylpiperydinyl‐1‐oxyl (TEMPO) Functionalized Benzoxazines Prepared with a One‐Pot Synthesis for Reactive/Crosslinkable Initiators of Nitroxide Mediated Polymerization

“…This result indicates that the methylene group of furan–CH 2 –N– is not involved in the TEMPO‐functionalization reaction. As a result, only the two –CH 2 – groups of the benzoxazine ring are reactive toward the radical transfer reaction, which is coincident to the results reported previously . The reaction conversion could be calculated from the relative ratios of the corresponding peak area.…”

“…The relative reactivity of the two groups was dependent on the substituents of the benzoxazine compounds. A detailed study and discussion was reported previously by this group . On the other hand, based on the experimental results, TEMPO‐functionalization takes place at the two reactive sites simultaneously in the early stage of the reaction.…”

Sulfur Radical Transfer and Coupling Reaction to Benzoxazine Groups: A New Reaction Route for Preparation of Polymeric Materials Using Elemental Sulfur as a Feedstock

“…In this work, benzoxazine compounds have been utilized as the radical transfer agent in SRTC reactions between S 8 and organic compounds. Radical transfer reactions to benzoxazine groups have been shown to generate benzoxazine radicals . Yagci and co‐workers reported benzoxazine‐initiated radical polymerization using the generated benzoxazine radicals as initiators.…”

“…Yagci and co‐workers reported benzoxazine‐initiated radical polymerization using the generated benzoxazine radicals as initiators. We have previously reported new reaction methods for the halogenation of benzoxazine compounds and the introduction of nitroxide groups to benzoxazine rings through radical transfer reactions to the benzoxazine rings . Using 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (Pa) as a model compound, the SRTC reaction between elemental sulfur and a benzoxazine ring was monitored with Fourier transform infrared spectroscopy (FTIR).…”

“…In this work, benzoxazine compounds have been utilized as the radical transfer agent [24,25] in SRTC reactions between S 8 and organic compounds. Radical transfer reactions to benzoxazine groups have been shown to generate benzoxazine radicals.…”