L-Hexyl-3-methylimidazolium bromide

The Michael-Arbuzov rearrangement is a basic reaction for the preparation of 4-coordinate species including phosphine oxides from 3-coordinate phosphorus esters, such as phosphinous esters. In most cases, the reaction requires a prolonged heating above 100 °C. Odinets et al. have now succeeded in carr5nng out the Arbuzov-reaction of ethyl diphenylphosphinite with a variety of alkyl halides in ionic liquids at or below 110 °C in short reaction times, mostly within half an hour. The best ionic liquid was l-hexyl-3-methylimidazolium bromide (Scheme 2). The recovered [hmim]Br could be recycled at least five times without a decrease in activity. 

The selective aerobic (O2) oxidative coupling of thiols in several imidazolium-based ionic liquids is studied in the absence of any base/metal catalysts. Disulfides are obtained from the corresponding thiols in good to excellent yields in l-hexyl-3-methylimidazolium bromide ([hmim]Br). Furthermore, a H NMR-based mechanistic study of the S-S bond formation demonstrated the cooperative role of halide anion and imidazolium cation of [hmimJBr. ... 

Li J-G, Hu Y-F, Sun S-F, Liu Y-S, Liu Z-C (2010) Densities and dynamic viscosities of the binary system (water + l-hexyl-3-methylimidazolium bromide) at different temperatures. J Chem Thermodyn 42 904—908... 

The compounds l-ethyl-3-methylimidazolium tetrafluoroborate ([EMlm][BF4]), l-butyl-3-methylimidazolium tetrafluoroborate ([B-Mlm][BF4]), l-hexyl-3-methylimidazolium tetrafluoroborate ([H-Mlm][BF4]) and l-butyl-3-methylimidazolium bromide ([BMlm]-[Br]) were used as ionic liquids. Some of these compounds are shown in Figure 1.7. Some properties are summarized in Table 1.3. 

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