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

17. Quantification of zwitterion betaine in betaine bis(trifluoromethylsulfonyl)imide and its influence on liquid–liquid equilibrium with water.

Author

Lee, Jaeseong, Fairley, Melissa, Goff, George S., and Brennecke, Joan F.

Subjects
BETAINE, ZWITTERIONS, LIQUID-liquid equilibrium, RARE earth metals
Abstract

Ionic liquids (ILs) have been proposed as extractants for separation of metals, including rare earth elements. In particular, protonated betaine bis(trifluoromethylsulfonyl)imide ([HBet][TFSI]) exhibits liquid–liquid phase behavior with water that can be tuned by complexation with various metals. Here we show that previously undetected neutral zwitterionic betaine formed during the IL synthesis can affect the phase behaviour. [ABSTRACT FROM AUTHOR]

Published
2023
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25. Ionic Liquid Stabilizes Olefin Facilitated Transport Membranes Against Reduction.

Author

Park, Sejoon, Morales‐Collazo, Oscar, Freeman, Benny, and Brennecke, Joan F.

Abstract

Separation of olefins from their paraffin analogs relies on energy‐intensive cryogenic distillation. Facilitated transport‐based membranes that reversibly and selectively bind olefins, but not paraffins, could save considerable amounts of energy. However, the chemical instability of the silver ion olefin‐binding carriers in such membranes has been a longstanding roadblock for this approach. We discovered long‐term carrier stability against extended exposure to hydrogen, a common contaminant in such streams. Based on UV/Vis absorption and Raman spectroscopy, along with XRD analysis results, certain ionic liquids solubilize silver ions, and anion aggregates surrounding the silver ion carriers greatly attenuate their reduction by hydrogen. Here, we report the stability of olefin/paraffin separation properties under continuous exposure to high pressure hydrogen, which addresses a critical technical roadblock in membrane‐based olefin/paraffin separation. [ABSTRACT FROM AUTHOR]

Published
2022
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27. Solubility of C[O.sub.2], C[H.sub.4], [C.sub.2][H.sub.6], [C.sub.2][H.sub.6], [O.sub.2], and [N.sub.2] in 1-hexyl-3-methylpyridinium Bis(trifluoromethylsulfonyl)imide: comparison to other ionic liquids

Author

Anderson, Jessica L., Dixon, Janielle K., and Brennecke, Joan F.

Subjects
Ionic solutions -- Research, Ionic solutions -- Chemical properties, Coordination compounds -- Research, Coordination compounds -- Chemical properties, Chemistry, Science and technology
Abstract

A study to examine the solubility of gases in ionic liquids (ILs) is conducted. Findings reveal a several fold increase in carbon dioxide solubility due to the use of fluoro-alkyl chains.

Published
2007

28. Characterization of the ability of C[O.sub.2] to act as an antisolvent for ionic liquid/organic mixtures

Author

Mellein, Beryln R. and Brennecke, Joan F.

Subjects
Ionic solutions -- Chemical properties, Hydrogen bonding -- Analysis, Carbon compounds -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

The ability of C[O.sub.2] to induce liquid/liquid-phase separation in mixtures of ionic liquids and organics is examined. The ability of C[O.sub.2] to act as an antisolvent has depended on the solubility of the C[O.sub.2] in the ionic liquid/organic mixture and strong hydrogen bonding between the ionic liquid and the organic has made it difficult for C[O.sub.2] to induce a liquid/liquid-phase secarbon compoundsparation.

Published
2007

29. Solvatochromic studies of ionic liquid/organic mixtures

Author

Mellein, Berlyn R., Aki, Sudhir N.V.K., Ladewski, Rebecca L., and Brennecke, Joan F.

Subjects
Ionic solutions -- Chemical properties, Organic dyes -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

The solvent strength of IL/organic mixtures is reported using Reichardt's dyes 30 and 33, Kamlet-Taft parameters and phenol blue. The results shows that the polarity of ILs is largely unaffected by the organic consolvent that is the probes are preferentially solvated by the ILs.

Published
2007

31. Anion effects on gas solubility in ionic liquids

Author

Anthony, Jennifer L., Anderson, Jessica L., Maginn, Edward J., and Brennecke, Joan F.

Subjects
Ionic solutions -- Research, Imidazole -- Electric properties, Anions -- Research, Chemicals, plastics and rubber industries
Abstract

A report on the solubilities of a variety of gases in several different ionic liquids is presented. It is concluded that the nature of the anion has the most significant influence on the gas solubilities.

Published
2005

32. High-pressure phase behavior of carbon dioxide with imidazolium-based ionic liquids

Author

Aki, Sudhir N.V.K., Mellein, Berlyn R., Saurer, Eric M., and Brennecke, Joan F.

Subjects
Ionic solutions -- Chemical properties, Carbon dioxide -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

The influence of anion, cation alkyl chain length, and additional alkyl substituents on the cation ring and on the solubility of CO2 in ILs at pressures to 150 bar is investigated. The results suggest that the solubility of carbon dioxide is strongly dependent on the choice of anion.

Published
2004

37. Hydroxyl radical reactivity with nitrobenzene in subcritical and supercritical water

Author

Feng, Junbo, Aki, Sudhir N.V.K., Chateauneuf, John E., and Brennecke, Joan F.

Subjects
Chemical reactions -- Analysis, Oxidation-reduction reaction -- Methods, Nitrobenzenes -- Chemical properties, Chemistry
Abstract

The bimolecular rate constants of the addition reaction between hydroxyl radical and nitrobenzene are determined in subcritical and supercritical water (SCW) at temperatures between ambient and 390 degree celsius. The measured bimolecular rate constants reported distinctly non-Arrhenius behavior from ambient to 350 degree celsius but increased in the slightly subcritical and supercritical region between 350 and 390 degree celsius.

Published
2002

38. Generation of Xanthenium and 9-phenylxanthenium carbocations in subcritical water and reactivity with amylamine

Author

Aki, Sudhir N. V. K., Feng, Junbo, Chateauneuf, John E., and Brennecke, Joan F.

Subjects
Amines -- Chemical properties, Ionization -- Research, Xanthine -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

A study of the ability of subcritical water to support ionic chemistry from the successful generation of (-R-xanthenium (R = H and C6H5) carbocations at temperatures up to 330 degrees Celsius from their respective alcohol precursors. The results show that for ion/neutral isoCoulombic reactions, require low-temperature Arrhenius parameters to predict the rate constants in water at higher temperatures and that the effect of pressure on the bimolecular rate constants in the temperature range of 22-330 degrees Celsius was negligible.

Published
2001

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