CuBr coordinated by the ionic liquid [N4MIM]Cl as a catalyst for biphasic ATRP in 1-allyl-3-methylimidazolium chloride ionic liquid

The ionic liquid 1-(triethylene-tetramine)ethyl-3-methyl chloride ([N 4 MIM]Cl) was first prepared to replace the organic ligand coordinating with CuBr to catalyze atom-transfer radical polymerization (ATRP) in ionic liquid system. [N 4 MIM]Cl was synthesized via the intermediate IL 1-chloroethyl-3-methyl chloride ([CeMIM]Cl) reacting with the aliphatic amine triethylene tetramine (TETA) and [CeMIM]Cl) was obtained by N′-alkylation of N -methylimidazole with 1,2-dichloroethane. This catalyst has been applied to the ATRP of methyl methacrylate (MMA) in the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) and presented a perfect catalytic performance. The chemical structures of the ILs obtained were confirmed by FTIR and 1 H   NMR. The coordination ability of [N 4 MIM]Cl was assessed by cyclic voltammetry (CV) and its coordination mechanism towards CuBr was discussed. The [N 4 MIM]Cl/CuBr catalyst system showed good controllability in the aforementioned ATRP reaction in [AMIM]Cl. The amount of residual Cu 2+ in the polymer product was determined by atomic absorption spectrometry (AAS) and the result showed that the Cu catalyst was easily separated from the obtained polymer. Thus, the coordinating IL could overcome the shortcomings of traditional organic ligands, such as poor compatibility with IL media resulting in the weakly catalytic performance and inferior separation of the catalyst from the polymer. It implied that the coordinating ionic liquid ([N 4 MIM]Cl) has highly promising application in the ATRP of ionic liquid system.