Rate constants for reaction of 1,2‐dimethylimidazole with benzyl bromide in ionic liquids and organic solvents

Abstract

The rate constant for the Menschutkin reaction of 1,2-dimethylimidazole with benzyl bromide to produce 3-benzyl-1,2-dimethylimidazolium bromide was determined in a number of ionic liquids and molecular organic solvents. The rate constants in 12 ionic liquids are in the range of (1.0-3.2) × 10 −3 L mol −1 s −1 and vary with the solvent anion in the order (CF 3 SO 2 ) 2 N − < PF 6 − < BF 4 − . Variations with the solvent cation (butylmethylimidazolium, octylmethylimidazolium, butyldimethylimidazolium, octyldimethylimidazolium, butylmethylpyrrolidinium, and hexyltributylammonium) are minimal. The rate constants in the ionic liquids are comparable to those in polar aprotic molecular solvents (acetonitrile, propylene carbonate) but much higher than those in weakly polar organic solvents and in alcohols. Correlation of the rate constants with the solvatochromic parameter E T (30) is reasonable within each group of similar solvents but very poor when all the solvents are correlated together. Better correlation is obtained for the organic solvents by using a combination of two parameters, π * (dipolarity/polarizibility) and α (hydrogen bond acidity), while additional parameters such as δ (cohesive energy density) do not provide any further improvement. C

A Kinetic Study of the Reaction between N,N‐Dimethyl‐p‐toluidine and its Electrogenerated Radical Cation in a Room Temperature Ionic Liquid

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Solvent effects on Grubbs’ pre-catalyst initiation rates

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Degradation of 1-butyl-3-methylimidazolium chloride ionic liquid in a Fenton-like system

“…Ionic liquids were also a subject of interest in advanced oxidation processes, not as target solutes however but as a novel reaction media for decomposition of various contaminants including CCl 4 , benzophenone, quinones or chlorinated phenols [21][22][23][24]. It was found that formation of stable radiolysis intermediates of ionic liquids may lead to their resistance towards oxidation, thus making them privileged for type of applications.…”