Comments and Additional Work on “High-Pressure Volumetric Properties of Imidazolium-Based Ionic Liquids: Effect of the Anion”

This works follows a publication of our group in J. Chem. Eng. Data2007, 52, 2204–2211 presenting high temperature and pressure density data for five imidazolium-based ionic liquids. At this period, very few ionic liquid density data were available in the literature, especially at high pressure, and the uncertainty of published results was calculated with respect to the literature data available for three of the five ionic liquids studied. Since 2007, the ionic liquid density databank has largely increased. In this work, a comparison of our published data in J. Chem. Eng. Data2007, 52, 2204–2211, with more than 1800 high pressure data coming from the literature up to December 2011 is presented to assess the uncertainty of our published values. The claimed uncertainty is close to 0.31 % for all IL density data sets except in the case of the [C1C2Im][EtSO4], where the uncertainty is up to 1.1 %. Reported data in J. Chem. Eng. Data2007, 52, 2204–2211, for this particular ionic liquid cannot be used as a reference. For this ionic liquid, new density measurements of the same sample batch have been remeasured by using the same experimental technique, and new experimental data presented herein are clearly higher than our previous published results. A 1H NMR analysis of the sample has confirmed hydrolysis of the ethylsulfate anion to ethanol and hydrogenate anion which explains the differences observed between our density data and the literature.

Mutual Solubilities of Ammonium-Based Ionic Liquids with Water and with Water/Methanol Mixture

Over the last two decades, ionic liquids have gained importance as alternative solvents to conventional VOCs in the field of homogeneous catalysis. This success is not only due to their ability to dissolve a large amount of metal catalysts, but it is also due to their potential to enhance yields of enantiopure products. The art of preparation of a specific enantiomer is a highly desired one and searched for in pharmaceutical industry. This work presents a study on solubility in water and in water/methanol mixture of a set of ILs composed of the bis (trifluoromethylsulfonyl) imide anion and of the N-alkyl-triethyl-ammonium cation (abbrev. [NR,222][NTf2]) with the alkyl chain R ranging from 6 to 12 carbons. Mutual solubilities between ILs and water, as well as between ILs and methanol/water mixture were investigated in detail. These solubilities were measured using two well-known and accurate experimental techniques based on a volumetric and a cloud-point methods. Both methods enabled us to measure the Tx diagrams reflecting the mutual solubilities between water (or water/methanol) and selected ILs in the temperature range from 293.15 to 338.15 K. The data were fitted by using the modified Flory-Huggins equation proposed by de Sousa and Rebelo and compared also with the prediction carried out by the Cosmo-RS methodology

Mapping Irreversible Electrochemical Processes on the Nanoscale: Ionic Phenomena in Li Ion Conductive Glass Ceramics

A scanning probe microscopy approach for mapping local irreversible electrochemical processes based on detection of bias-induced frequency shifts of cantilevers in contact with the electrochemically active surface is demonstrated. Using Li ion conductive glass ceramic as a model, we demonstrate near unity transference numbers for ionic transport and establish detection limits for current-based and strain-based detection. The tip-induced electrochemical process is shown to be a first-order transformation and nucleation potential is close to the Li metal reduction potential. Spatial variability of the nucleation bias is explored and linked to the local phase composition. These studies both provide insight into nanoscale ionic phenomena in practical Li-ion electrolyte and also open pathways for probing irreversible electrochemical, bias-induced, and thermal transformations in nanoscale systems.

Isolation and Characterisation of 1-Alkyl-3- Methylimidazolium Chloride Ionic Liquid-Tolerant and Biodegrading Marine Bacteria

The aim of this study was to isolate and identify marine-derived bacteria which exhibited high tolerance to, and an ability to biodegrade, 1-alkyl-3-methylimidazolium chloride ionic liquids. The salinity and hydrocarbon load of some marine environments may induce selective pressures which enhance the ability of microbes to grow in the presence of these liquid salts. The isolates obtained in this study generally showed a greater ability to grow in the presence of the selected ionic liquids compared to microorganisms described previously, with two marine-derived bacteria, Rhodococcus erythropolis and Brevibacterium sanguinis growing in concentrations exceeding 1 M 1-ethyl-3-methylimidazolium chloride. The ability of these bacteria to degrade the selected ionic liquids was assessed using High Performance Liquid Chromatography (HPLC), and three were shown to degrade the selected ionic liquids by up to 59% over a 63-day test period. These bacterial isolates represent excellent candidates for further potential applications in the bioremediation of ionic liquid-containing waste or following accidental environmental exposure.

Enhanced antimicrobial activities of 1-alkyl-3-methyl imidazolium ionic liquids based on silver or copper containing anions

We have developed a series of 1-alkyl-3-methylimidazolium tetrachlorocuprate(II) and dibromoargentate(I) ionic liquids with enhanced antimicrobial activity when compared with 1-alkyl-3-methylimidazolium chloride ionic liquids. These new ionic liquids proved to be effective against a range of pathogenic bacteria and fungi.

Thermophysical properties of ionic liquids

Ionic liquids have received significant interest from research groups and industry for a range of novel applications. Many of these require a thorough knowledge of the thermophysical properties of the pure fluids and their mixtures. Despite this need, the necessary experimental data for many properties are scarce and often inconsistent between the various sources. However, by using accurate data, predictive physical models can be developed which are highly useful, and some would consider essential, if ionic liquids are to realise their full potential. This is particularly true if one can use them to design new ionic liquids which maximise key desired attributes. This paper will review some of the recent advances in our understanding, prediction and correlation of selected ionic liquid physical properties.

Flow patterns and pressure drop of ionic liquid-water two-phase flows in microchannels

The two-phase flow of a hydrophobic ionic liquid and water was studied in capillaries made of three different materials (two types of Teflon, FEP and Tefzel, and glass) with sizes between 200µm and 270µm. The ionic liquid was 1-butyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, with density and viscosity of 1420kgm and 0.041kgms, respectively. Flow patterns and pressure drop were measured for two inlet configurations (T- and Y-junction), for total flow rates of 0.065-214.9cmh and ionic liquid volume fractions from 0.05 to 0.8. The continuous phase in the glass capillary depended on the fluid that initially filled the channel. When water was introduced first, it became the continuous phase with the ionic liquid forming plugs or a mixture of plugs and drops within it. In the Teflon microchannels, the order that fluids were introduced did not affect the results and the ionic liquid was always the continuous phase. The main patterns observed were annular, plug, and drop flow. Pressure drop in the Teflon microchannels at a constant ionic liquid flow rate, was found to increase as the ionic liquid volume fraction decreased, and was always higher than the single phase ionic liquid value at the same flow rate as in the two-phase mixture. However, in the glass microchannel during plug flow with water as the continuous phase, pressure drop for a constant ionic liquid flow rate was always lower than the single phase ionic liquid value. A modified plug flow pressure drop model using a correlation for film thickness derived for the current fluids pair showed very good agreement with the experimental data. © 2013 Elsevier Ltd.

Controlled fragrance delivery in functionalised ionic liquid-enzyme systems

It is often believed that both ionic liquids and surfactants generally behave as non-specific denaturants of proteins. In this paper, it is shown that amphiphilic ionic liquids bearing a long alkyl chain and a target molecule, where the target molecule is appended via a carboxylic ester functionality, can represent super-substrates that enable the catalytic activity of an enzyme, even at high concentrations in solution. Menthol has been chosen as the target molecule for slow and controlled fragrance delivery, and it was found that the rate of the menthol release can be controlled by the chemical structure of the ionic liquid. At a more fundamental level, this study offers an insight into the complex hydrophobic, electrostatic, and hydrogen bond interactions between the enzyme and substrate.

Lead(II) chloride ionic liquids and organic/inorganic hybrid materials - a study of chloroplumbate(II) speciation

A range of chloroplumbate(II) organic salts, based on the two cations, 1-ethyl-3-methylimidazolium and trihexyl(tetradecyl) phosphonium, was prepared by ionothermal synthesis. Depending on the structure of the organic cation and on the molar ratio of PbCl2 in the product,.PbCl2, the salts were room-temperature ionic liquids or crystalline organic/inorganic hybrid materials. The solids were studied using Raman spectroscopy; the crystal structure of [C(2)mim]{PbCl3} was determined and shown to contain 1D infinite chloroplumbate(II) strands formed by edge-sharing tetragonal pyramids of pentacoordinate (PbCl5) units. The liquids were analysed using Pb-207 NMR and Raman spectroscopies, as well as viscometry. Phase diagrams were constructed based on differential scanning calorimetry (DSC) measurements. Discrete anions: [PbCl4](2-) and [PbCl3](-), were detected in the liquid state. The trichloroplumbate(II) anion was shown to have a flexible structure due to the presence of a stereochemically-active lone pair. The relationship between the liquid phase anionic speciation and the structure of the corresponding crystalline products of ionothermal syntheses was discussed, and the data were compared with analogous tin(II) systems.

Controlled chemistry of Moisture Sensitive Reagents in Ionic Liquids

Many reactions involving phosphorus reagents require highly anhydrous and inert conditions for their successful implementation. In particular, the use of PCl3 and its derivatives for synthesis is often hampered by the inherent sensitivity of the materials themselves. Ionic liquids are emerging as green alternative solvents for a range of processes, and in particular have proven to be excellent media for highly sensitive phosphorus reagents without the need for anhydrous or inert conditions. Herein, we report the use of ionic liquids as both storage and reaction media which allows difficult and sensitive chemistry to be achieved in a more accessible manner.

Transcameral suture to prevent tube-corneal touch after glaucoma drainage device implantation: a new surgical technique

PURPOSE: To report a new technique to correct tube position in anterior chamber after glaucoma drainage device implantation.

PATIENT AND METHODS: A patient who underwent a glaucoma drainage device implantation was noted to have the tube touching the corneal endothelium. A 10/0 polypropylene suture with double-armed 3-inch long straight needle was placed transcamerally from limbus to limbus, in the superior part of the eye, passing the needle in front of the tube.

RESULTS: The position of the tube in the anterior chamber was corrected with optimal distance from corneal endothelium and iris surface. The position remained satisfactory after 20 months of follow-up.

CONCLUSIONS: The placement of a transcameral suture offers a safe, quick, and minimal invasive intervention for the correction of the position of a glaucoma drainage device tube in the anterior chamber.

Simultaneous use of mitomycin-C with Baerveldt implantation

BACKGROUND AND OBJECTIVE: To evaluate the outcome of Baerveldt implantation with adjunctive mitomycin-C in cases of complicated glaucoma. PATIENTS AND METHODS: The authors reviewed the charts of all patients who had undergone Baerveldt implantation with mitomycin-C between January 1993 and March 1995. Success was defined before data collection as an intraocular pressure (IOP) between 5 and 21 mm Hg, with or without medications. The success rate was calculated using the Kaplan-Meier actuarial method. RESULTS: Twenty-nine patients were identified. The mean preoperative IOP was 33.6 mm Hg, with an average of 2.0 antiglaucoma medications. The probability of success at 6 and 12 months for patients who received mitomycin-C during Baerveldt implantation was 82.4% and 73.3%, respectively. Choroidal effusion with a flat anterior chamber (10.3%), corneal edema (6.8%), and conjunctival erosion (6.8%) were the most frequent complications. CONCLUSION: In this retrospective series of complicated glaucoma, the implantation of a Baerveldt drainage device with adjunctive mitomycin-C had a satisfactory outcome. The complications encountered and the clinical efficacy were comparable to those of previously reported series in which mitomycin-C was not used.

Mitomycin-C supplemented trabeculectomy, phacoemulsification, and foldable lens implantation

Purpose: To evaluate the outcome of combined mitomycin-C filtering surgery, phacoemulsification, and foldable intraocular lens (IOL) implantation. Setting: Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA. Methods: This retrospective study evaluated 182 eyes of 174 patients who had combined mitomycin-C trabeculectomy, phacoemulsification, and insertion of a foldable IOL through a 3.5 mm incision. Success of the combined procedure was defined as intraocular pressure (IOP) below 21 mm Hg, with or without medications, and no serious complication. Success rates were calculated using the Kaplan-Meier actuarial method. Results: Mean follow-up was 16.7 months ± 5.4 (SD). The probability of success at 6, 12, 18, and 24 months was 98.3, 95.6, 90.6, and 88.0%, respectively. When compared with preoperativety, visual acuity improved one or more lines in 148 eyes (81.3%) and worsened one or more lines in 15 (8.2%); 111 eyes (61.0%) achieved visual acuity of 20/40 or better. The most frequent complication was posterior capsule opacification requiring capsulotomy, which occurred in 22 cases (12.0%). Conclusion: The 1 year and 2 year IOP control rate of combined mitomycin-C filtering procedures and phacoemulsification in glaucoma patients was high.