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857 results on '"Brennecke, Joan F."'

203. Homogeneous organic reactions as mechanistic probes in supercritical fluids

Author

Brennecke, Joan F. and Chateaneuf, John E.

Subjects
Organic compounds -- Research, Supercritical fluid chromatography -- Research, Solvents -- Research, Chemistry
Abstract

Several studies have been carried out to analyze the reactions of probes of molecular structure and its influence on reactivity in supercritical fluids. A number of these studies have examined the homogeneous reactions of organic compounds to determine the effects of solvent structure. Results indicated that primary effects on reaction rates, selectivities and mechanisms can be differentiated. In addition, solvent shells do not support their integrity long enough to generate cage effects in the decomposition process.

Published
1999

204. Molecular trees for green chemistry

Author

Brennecke, Joan F.

Subjects
Solvents -- Research, Surface active agents -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

New research that shows the use of a fluorinated dendrimer to extract hydrophilic compounds from water into liquid carbon dioxide (CO2) could considerably expand the use of CO2 as a solvent. Such 'smart' CO2 agents can extend CO2's ability as a solvent and could replace chlorinated liquids in cleaning operations. Other uses could include the extraction of pharmaceutical products from fermentation broths. Details of the study are presented.

Published
1997

214. Solubility of CO2 in [1-n-butylthiolanium] [Tf2N] + toluene mixtures: liquid-liquid phase split separation and modelling.

Author

Canales, Roberto I., Lubben, Michael J., Gonzalez-Miquel, Maria, and Brennecke, Joan F.

Subjects
CARBON dioxide, LIQUID-liquid interfaces, AROMATIC compound derivatives, TOLUENE, IONIC liquids, TERNARY alloys
Abstract

Carbon dioxide has been shown to be an effective antisolvent gas for separating organic compounds from ionic liquids (ILs) by inducing a liquid-vapour to liquid-liquid-vapour transition. Using carbon dioxide, toluene can be separated from imidazolium, phosphonium and pyridinum cation-based ILs with the bis(trifluoromethylsulfonyl)imide anion, which is relatively hydrophobic and has a high toluene solubility. A new IL with relatively low viscosity is tested here for the same toluene separation process: 1-n-butylthiolanium bis(trifluoromethylsulfonyl)imide. Carbon dioxide solubility in binary and ternary systems containing toluene and 1-n-butylthiolanium bis(trifluoromethylsulfonyl)imide is measured at 298.15 and 313.15K up to 7.4 MPa. Solubility behaviour in this IL is similar to imidazolium-based ILs with the same anion. However, phase split pressures are lower when 1-n-butylthiolanium bis (trifluoromethylsulfonyl)imide is used instead of 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide at the same conditions of temperature and initial composition of toluene in the IL. Solubility data are modelled with the conductor-like screening model for real solvents combined with the Soave-Redlich-Kwong equation of state, which provides good qualitative results. [ABSTRACT FROM AUTHOR]

Published
2015
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217. Guidelines for reporting of phase equilibrium measurements (IUPAC Recommendations 2012)

Author

Chirico, Robert D., primary, de Loos, Theodoor W., additional, Gmehling, Jürgen, additional, Goodwin, Anthony R. H., additional, Gupta, Sumnesh, additional, Haynes, William M., additional, Marsh, Kenneth N., additional, Rives, Vicente, additional, Olson, James D., additional, Spencer, Calvin, additional, Brennecke, Joan F., additional, and Trusler, J. P. Martin, additional

Published
2012
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218. Solubility of Nitrogen in Ionic Liquids at 295–353 K and Pressures to 140 bar

Author

Bentley, Caitlin L., Song, Tangqiumei, Morales-Collazo, Oscar, and Brennecke, Joan F.

Abstract

Ionic liquids (ILs) have been evaluated extensively as post-combustion CO2capture solvents, with CO2solubility data available for a large number of ILs. However, data for the solubility of the less-soluble gas component, N2, are sparse. Therefore, the solubility of N2was measured gravimetrically at pressures up to 140 bar in 12 ILs containing imidazolium, ammonium, pyrrolidinium, and phosphonium cations paired with bis(trifluoromethanesulfonyl)imide ([TFSI]−), dicyanamide ([DCA]−), methanesulfonate ([MeSO3]−), tetrafluoroborate [BF4]−), and triflate ([TfO]−) anions. Increasing the alkyl chain length from ethyl to hexyl to decyl in alkylimidazolium bis(trifluoromethanesulfonyl)imide ILs increased the N2solubility. The same effect was observed with phosphonium cations paired with the bis(trifluoromethylsulfonyl)imide anion. Nitrogen solubility in ILs with the 1-ethyl-3-methylimidazolium cation followed the order [DCA]−< [MeSO3]−< [BF4]−< [TfO]−< [TFSI]−. Generally, regardless of the IL structure, the N2solubility increased with increasing IL molar volume. For ILs with similar chemical composition and molar volume (i.e., ILs with tetraalkylammonium and pyrrolidinium cations), N2was less soluble in the IL with the cyclic cation. The absorption of N2in bis(trifluoromethylsulfonyl)imide ILs did not depend significantly on temperature. However, [emim][BF4] had a significant positive enthalpy of N2absorption. These N2solubility data, along with the readily available CO2solubilities in ILs, is critical to evaluating ILs for post-combustion carbon capture processes.

Published
2023
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232. Thermodynamic and thermophysical properties of the reference ionic liquid: 1-Hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide (including mixtures). Part 1. Experimental methods and results (IUPAC Technical Report)

Author

Marsh, Kenneth N., primary, Brennecke, Joan F., additional, Chirico, Robert D., additional, Frenkel, Michael, additional, Heintz, Andreas, additional, Magee, Joseph W., additional, Peters, Cor J., additional, Rebelo, Luis Paulo N., additional, and Seddon, Kenneth R., additional

Published
2009
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242. Preface

Author

Brennecke, Joan F., primary, Rogers, Robin D., additional, and Seddon, Kenneth R., additional

Published
2007
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246. Liquid-liquid phase split in ionic liquid + toluene mixtures induced by CO2.

Author

Canales, Roberto I. and Brennecke, Joan F.

Subjects
LIQUID-liquid interfaces, IONIC liquids, TOLUENE, CARBON dioxide, BINARY mixtures
Abstract

High pressure carbon dioxide was dissolved in ionic liquid + toluene mixtures to obtain the conditions of pressure and composition where a liquid-liquid phase split occurs at constant temperature. Ionic liquids (ILs) with four different cations paired with the bis(trifluoromethylsulfonyl)imide ([Tf2N]−) anion were selected: 1-hexyl-3-methylimidazolium ([hmim]+), 1-hexyl-3-methylpyridinium ([hmpy]+), triethyloctylphosphonium ([P2228]+), and tetradecyltrihexylphosphonium ([P66614]+). The solubility of CO2 was measured in the liquid mixtures at temperatures between 298 and 333 K and at pressures up to 8 MPa, or until the second liquid phase appeared, for initial liquid phase compositions of 0.30, 0.50, and 0.70 mole fraction of IL. Ternary isotherms were compared with the binary solubility of CO2 in each IL and pure toluene. The lowest pressure for separating toluene in a second liquid phase was achieved by decreasing the temperature of the system, increasing the amount of toluene in the initial liquid mixture and using [hmim][Tf2N]. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2968-2976, 2015 [ABSTRACT FROM AUTHOR]

Published
2015
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247. Characterization of Imidazolium Chloride Ionic Liquids Plus Trivalent Chromium Chloride for Chromium Electroplating.

Author

Liyuan Sun and Brennecke, Joan F.

Subjects
*CHROMIUM chlorides, *IONIC liquids, *MIXTURES, *ELECTROPLATING, *ELECTROCHEMISTRY, *WATER
Abstract

A series of mixtures consisting of the ionic liquids (ILs) 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, and 1-hexyl-3-methylimidazolium chloride ([emim][Cl], [bmim][Cl], and [hmim][Cl], respectively) and trivalent chromium chloride have been prepared. Physicochemical and electrochemical properties of these mixtures have been studied and the potential applications of these mixtures for chromium electroplating, as an alternative to the conventional hard chromium electroplating processes using hexavalent chromium baths, have been examined. To optimize the transport properties of the mixtures, different amounts of ultrapure water were added to the Cr(III) salt-IL mixtures, although the ultimate goal is to reduce or eliminate water. As shown previously for choline chloride/Cr(III) salt mixtures, we found that the physicochemical and electrochemical properties of the mixtures are affected by the relative water content. Our preliminary electroplating results show that these types of Cr(III) salt-IL mixtures could be promising alternatives to Cr(VI) containing baths for chromium electroplating applications with the advantage of avoiding the use of highly toxic hexavalent chromium. [ABSTRACT FROM AUTHOR]

Published
2015
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