Recent Progress on Transition Metal Catalyst Separation and Recycling in ATRP

Abstract

Atom transfer radical polymerization (ATRP) is a versatile and robust tool to synthesize a wide spectrum of monomers with various designable structures. However, it usually needs large amounts of transition metal as the catalyst to mediate the equilibrium between the dormant and propagating species. Unfortunately, the catalyst residue may contaminate or color the resultant polymers, which limits its application, especially in biomedical and electronic materials. How to efficiently and economically remove or reduce the catalyst residue from its products is a challenging and encouraging task. Herein, recent advances in catalyst separation and recycling are highlighted with a focus on (1) highly active ppm level transition metal or metal free catalyzed ATRP; (2) post-purification method; (3) various soluble, insoluble, immobilized/soluble, and reversible supported catalyst systems; and (4) liquid-liquid biphasic catalyzed systems, especially thermo-regulated catalysis systems.

Synthesis of cationic star polymers by simplified electrochemically mediated ATRP

“…Atom transfer radical polymerization (ATRP) is proven to be one of the most versatile reversible deactivation radical polymerization (RDRP) methods that enables the preparation of polymers with controlled molecular weights (MWs), narrow molecular weight distributions (M w /M n , MWDs), and targeted degrees of polymerization (DP) [1][2][3][4][5][6][7][8][9][10][11][12][13]. The advent of low amount catalyst ATRP system, such as simplified electrochemically mediated ATRP (seATRP) [14] offers more environmentally friendly reaction conditions for the synthesis of polymers [15].…”

A strategy to enhance CO2 permeability of well-defined hyper-branched polymers with dense polyoxyethylene comb graft

“…The ATRP has been employed for living polymerization of various monomers including methacrylates [31][32][33], and POEM graft chains with narrow molecular weight distribution would result from the polymerization technique. In brief, the macroinitiator was dissolved in N-methylpyrrolidone (NMP), and predetermined amount of POEM, CuCl, and bpy were added to the solution.…”

Photoinduced controlled/“living” polymerization of methyl methacrylate with flavone as photoinitiator

“…1 After sixty years of development, living polymerization has been divided into three classes of powerful techniques: nitroxide mediated radical polymerization (NMP), 2 reversible addition-fragmentation transfer polymerization (RAFT), 3 and atom transfer radical polymerization (ATRP). [4][5][6] Among them, ATRP is one of the most rapidly developing areas in living polymerization. ATRP is suitable for a number of monomers under a variety of reaction conditions.…”