Imidazolium Ethyl Sulfate Research Articles

Effects of water-miscible ionic liquids on cell growth and nitro reduction using Clostridium sporogenes

Water miscible ionic liquids had various effects on the physiology of Clostridium sporogenes when tested as additives in culture media or reaction media for reduction of nitrobenzene. 2-Hydroxy ethyl trimethyl-ammonium dimethyl phosphate ([EtOHNMe3][Me2PO4]) and N,N-dimethylethanolammonium acetate (DMEAA) increased the growth rate of C. sporogenes by as much as 28%, suggesting that they were either metabolised or increased the availability of nutrients. By contrast, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMim][BF4]) and AMMOENG™ 100 inhibited growth. Although 1-ethyl-3-methyl imidazolium ethylsulfate ([EMim][EtSO4]; 2% w/v) inhibited growth by 58%, it was sufficiently non-toxic to allow efficient reduction of nitrobenzene using harvested cells, providing aniline yields up to 79%. The high product yield with reactions in [EMim][EtSO4] represented a significant improvement over conventional solvents, since the yield was only 8% in aqueous ethanol (4% v/v) and 45% in a biphasic heptane/aqueous system (phase ratio 0.33). The ionic liquid appeared to suppress unproductive substrate consumption by an unknown mechanism

Liquid-liquid Equilibria of ([C2mim][EtSO4] + Thiophene + 2,2,4-Trimethylpentane) and ([C2mim][EtSO4] + Thiophene + Toluene): Experimental Data and Correlation

Liquid + liquid equilibrium data for (1-ethyl-3-methyl imidazolium ethyl sulfate + thiophene + 2,2,4-trimethylpentane) and (1-ethyl-3-methyl imidazolium ethyl sulfate + thiophene + toluene) have been determined at 298.15 K and atmospheric pressure. The ionic liquid has a great capacity to dissolve not only thiophene but also the toluene, being practically immiscible with 2,2,4-trimethylpentane. Equilibrium data of systems with toluene have been fairly well correlated with the NRTL and UNIQUAC equations but for the system with 2,2,4-trimethylpentane high deviations have been found with both equations.

Ionic-Liquid Lubrication of Sliding MEMS Contacts: Comparison of AFM Liquid Cell and Device-Level Tests

Lubrication of microelectromechanical systems (MEMS) became very critical as the devices became complex and its reliability began to deteriorate. In this paper, ionic liquids (ILs) with low volatility and high environmental stability were investigated as lubricants for sliding MEMS devices. A method that is based on atomic force microscopy (AFM) with a liquid cell was developed to study friction and wear properties of surfaces lubricated with ILs, having a systematic variation in molecular geometry and chemistry. Six-member pyridinium and five-member imidazolium rings are compared as cations in ethyl methyl pyridinium and ethyl methyl imidazolium ethyl sulfate; influence of short and long alkyl chain lengths on lubrication is studied with butyl methyl pyrrolidinium and hexyl methyl pyrrolidinium bis(trifluro methyl sulfonyl) imide. Formation of a surface-screening cation layer was discovered and linked to low friction and wear of IL-lubricated hydrogenated-silicon (H-Si) substrates. Several promising IL lubricants were identified from the AFM study and were tested in real MEMS motor devices. The friction and wear data obtained for these tests showed good correlation with the failure life span of lubricated MEMS motors. This supports a conclusion that the AFM-liquid-cell technique can be used in screening IL lubricants for MEMS devices.

A comparative study on solvents for separation of tert-amyl ethyl ether and ethanol mixtures. New experimental data for 1-ethyl-3-methyl imidazolium ethyl sulfate ionic liquid

Ionic liquids have potential applications on separation technologies, as solvents for liquid extraction, gas absorbers and others. In this work, the ability of 1-ethyl-3-methyl imidazolium ethyl sulfate, [emim][ EtSO 4 ], to carry out the separation of tert-amyl ethyl ether and ethanol mixtures has been studied. New experimental LLE data for the ternary system are reported. Data correlation was done by means of the NRTL equation with satisfactory results ( rmsd = 0.429 % ) . Extraction process was studied by means of solute distribution ratio and selectivity of the ionic liquid. Results were compared to other solvents from the literature. Solute distribution ratio for [emim][ EtSO 4 ] was acceptable (higher than 1) and selectivity was better than for other solvents. Then, extraction processes were also simulated using conventional software and obtained results are shown for comparison. Best TAEE recovery was obtained with [emim][ EtSO 4 ] and water.

Great increase of the electrical conductivity of ionic liquids in aqueous solutions

Here we present measurements of the electrical conductivity and density for six ionic liquids (ILs) in aqueous solutions at 25.0 °C and atmospheric pressure. The analysed ILs are: two different mixtures of AlBr 3 + 1-ethyl-3-methyl imidazolium bromide (called here EMIM-AlBr 3), a mixture of AlBr 3 + 1-ethyl pyridinium bromide (EPYR-AlBr 3), another mixture of AlCl 3 + 1-ethyl-3-methyl imidazolium chloride (EMIM-AlCl 3), 1-ethtyl-3-methyl imidazolium tetrafluoroborate (EMIM-BF 4) and 1-ethyl-3-methyl imidazolium ethylsulfate (EMIM-ES, commercially known as ECOENG™ 212). For the EMIM-AlBr 3 we have tailored (and then measured) two ILs with two different molar fractions of AlBr 3 equal to 0.60 and 0.35, so that one is Lewis acidic and the other one Lewis basic. The density is seen to monotonically decrease when water is added, while the electrical conductivity dramatically increases up about 10 times (with a maximum of 30 times) for selected mixtures of each ionic liquid (IL) plus water. For the majority of systems the peak appears at about 50 wt.%, which corresponds to a molar fraction of IL in the mixture about 0.12. We have extracted the equivalent conductance and we have compared it with aqueous solutions of the precursor salts. Finally, as the data measured do not adapt to current theoretical expressions, we have developed a new theoretical approach based in conventional hole theory.