RAFT-Mediated Polymerization of Styrene in Readily Biodegradable Ionic Liquids

Abstract

Two novel and readily biodegradable ionic liquids were used as solvents in the successful reversible addition-fragmentation chain transfer (RAFT)-mediated radical polymerization of styrene. The polymerizations reached high conversions with slightly higher rates than that observed in toluene, and the molecular weight distributions were consistent with that of an ideal "living" radical polymerization. This represents a significant advance as previous attempts to conduct RAFT-mediated polymerizations of styrene in ionic liquids had failed. With a detailed kinetic analysis we found that the ratio of termination to propagation rate constants remained relatively constant over the conversion range, suggesting that "trapped" or "protected" radicals were not present in our systems.

Living Radical Polymerization by the RAFT Process - A Second Update

“…5). [255] The polymerization kinetics were similar to those for toluene solution. Note that previous attempts to polymerize St in conventional imidazolium ionic liquids were unsuccessful.…”

“…AA [251] BA [251,252] BA [253] MA [54,252] St [254,255] HPA [251] St [256] SMe [251] BP/NPMI [257] S S 93 [216] BA [216] (BA) [216] S S 94* [255] AEP [87] BA [62,216] (BA) [216] TFPA [93] MMBL [258] AcS [259] St [260] St [261] PFS [93] NIPAM [262,263] St/MMBL [258] MMA/BA [62] BP/NPMI [257] BP/NMMI [257] BP/NEMI [257] TFPA-b-tBA [93] PFS-b-tBA [93] …”

New ionic liquids with hydrolytically stable anions as alternatives to hexafluorophosphate and tetrafluoroborate salts in the free radical polymerization and preparation of ion-conducting composites

“…26,27 The major advantages of using of ILs in free radical polymerization are (a) their ability to dissolve a wide range of organic and ionic compounds, including monomers and polymers; (b) the acceleration of the polymerization reaction; (c) the safety of the process, in particular because of the nonflammability and nonvolatility of ILs and (d) the possibility of solvent recycling. These intriguing features have stimulated interest in the application of ILs as reaction media in other types of radical polymerization, including the reversible addition-fragmentation chain transfer [28][29][30][31] process, polymerization with atom (atom transfer radical polymerization), [32][33][34][35][36][37][38][39][40][41][42][43][44] group 45 or charge 46 transfer, nitroxide-mediated polymerization 47 and some others. [48][49][50] The majority of published reports 14,15,19,23,29,30,32,34,37,39,51 devoted to polymerization in ILs as reaction media only deals with the investigation of commonly known ILs with fluorinated anions such as tetrafluoroborate, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide ILs.…”

Grignard Reactions in Pyridinium and Phosphonium Ionic Liquids

“…These ILs have been evaluated as reaction media for a range of organic reactions, including Diels-Alder reactions, [22] palladium-catalysed hydrogenation reactions, [22] Sonogashira coupling reactions [23] as well as the RAFT-mediated polymerization of styrene. [24] The presence of a labile ester group clearly limits the utility of these ionic liquids as reaction media. Herein we report the synthesis of new pyridinium and phosphonium ILs that possess ether functionality as well as their use as solvents for Grignard reactions.…”