N. Llewellyn Lancaster

The role of hydrogen bonding in controlling the selectivity of Diels–Alder reactions in room-temperature ionic liquids

The reaction of cyclopentadiene with methyl acrylate has been investigated in a range of ionic liquids. The origin of the endo-selectivity for the reactions and associated rate enhancements has been attributed to a hydrogen bond formed between the cation of the ionic liquid and the methyl acrylate.

Precise temperature control in microfluidic devices using Joule heating of ionic liquids

Microfluidic devices for spatially localised heating of microchannel environments were designed, fabricated and tested. The devices are simple to implement, do not require complex manufacturing steps and enable intra-channel temperature control to within +/-0.2 degrees C. Ionic liquids held in co-running channels are Joule heated with an a.c. current. The nature of the devices means that the internal temperature can be directly assessed in a facile manner.

A study of halide nucleophilicity in ionic liquids

The relative nucleophilicity of chloride, bromide and iodide anions in [bmim][BF4] ionic liquid has been measured by studying their reaction with methyl p-nitrobenzenesulfonate ([bmim] = 1-butyl-3-methylimidazolium cation). It has been found that iodide is the most nucleophilic halide, and that chloride and bromide have approximately equal nucleophilicities (Cl− is slightly more nucleophilic than Br−) in [bmim][BF4]. Activation energies for the reaction of chloride and bromide with methyl p-nitrobenzenesulfonate have been calculated. The relative nucleophilicity of the halides has been compared with that observed in molecular solvents and in a tetraalkylammonium tetraalkylboride ionic liquid.

Aromatic nitrations in ionic liquids: the importance of cation choice

Aromatic substrates can be nitrated in high yields and with efficient use of the nitrating agent in ionic liquids, although a suitably inert ionic liquid cation must be used.

The efficacy of ‘Claycop’ in the dinitration of toluene

Claycop and acetic anhydride in tetrachloromethane are modestly catalytic and regioselective in the mononitration of toluene, but are neither catalytic nor regioselective in the nitration of 2-nitrotoluene.