TY - GEN
T1 - Pulse radiolysis studies of reaction kinetics in ionic liquids
AU - Neta, P.
AU - Behar, D.
AU - Grodkowski, J.
PY - 2003
Y1 - 2003
N2 - Reaction rate constants were determined by pulse radiolysis in the ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate and tetrafluoroborate, N-butylpyridinium tetrafluoroborate, and methyltributylammonium bis(trifluoromethylsulfonyl)imide (R4NNTf2). Oxidation of chlorpromazine and Trolox by CCl3O2 · radicals was studied in all the ionic liquids and oxidation of chlorpromazine by Br 2·-" radicals was studied in R 4NNTf2. Reduction of quinones and other compounds was studied both in R4NNTf2 and in the pyridinium ionic liquids. The ionic liquids behave as solvent with much lower polarity than water and also inhibit reactions due to their high viscosity. However, electron transfer from the N-butylpyridinyl radical to various acceptors is more rapid than the diffusion-controlled limit, suggesting an electron hopping mechanism. Electron transfer between methyl viologen and quinones takes place several orders of magnitude more slowly in this ionic liquid than in water or 2-PrOH and the direction of the electron transfer is solvent dependent. In contrast, addition and abstraction reactions of ·CF3 radicals in R 4NNTf2 are only slightly slower than those in water and acetonitrile.
AB - Reaction rate constants were determined by pulse radiolysis in the ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate and tetrafluoroborate, N-butylpyridinium tetrafluoroborate, and methyltributylammonium bis(trifluoromethylsulfonyl)imide (R4NNTf2). Oxidation of chlorpromazine and Trolox by CCl3O2 · radicals was studied in all the ionic liquids and oxidation of chlorpromazine by Br 2·-" radicals was studied in R 4NNTf2. Reduction of quinones and other compounds was studied both in R4NNTf2 and in the pyridinium ionic liquids. The ionic liquids behave as solvent with much lower polarity than water and also inhibit reactions due to their high viscosity. However, electron transfer from the N-butylpyridinyl radical to various acceptors is more rapid than the diffusion-controlled limit, suggesting an electron hopping mechanism. Electron transfer between methyl viologen and quinones takes place several orders of magnitude more slowly in this ionic liquid than in water or 2-PrOH and the direction of the electron transfer is solvent dependent. In contrast, addition and abstraction reactions of ·CF3 radicals in R 4NNTf2 are only slightly slower than those in water and acetonitrile.
UR - http://www.scopus.com/inward/record.url?scp=34249663103&partnerID=8YFLogxK
U2 - 10.1021/bk-2003-0856.ch032
DO - 10.1021/bk-2003-0856.ch032
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AN - SCOPUS:34249663103
SN - 9780841238565
T3 - ACS Symposium Series
SP - 397
EP - 409
BT - Ionic Liquids as Green Solvent - Progress and Prospects
PB - American Chemical Society
ER -