Towards a Better Understanding of 'Delocalized Charge' in Ionic Liquid Anions

2007 ◽  
Vol 60 (1) ◽  
pp. 15 ◽  
Author(s):  
Ekaterina I. Izgorodina ◽  
Maria Forsyth ◽  
Douglas R. MacFarlane
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Melting Point ◽  
Proton Affinity ◽  
Molten Salts ◽  
Charge Delocalization ◽  
Range Of Values

One of the main characteristics that are attributed to ionic liquids (especially those with a low melting point) is that the anions comprising the ionic liquids possess a certain degree of charge delocalization as compared to anions in traditional molten salts. Based on the proton affinity equilibrium we proposed a new energetic criterion that can be used as a measure of charge delocalization. The proposed proton affinity comparison quantifies the extent to which ionic liquid anions are delocalized. Thus it should lead to a better understanding towards the design of task-specific ionic liquids. Therefore, this criterion can be applied to newly designed anions to assure that the extent of charge delocalization falls within the same range of values on the proton affinity scale as other commonly used ionic liquid anions.

Synthesis and Characterization of Super-Molecular Ionic Liquids

2011 ◽  
Vol 197-198 ◽  
pp. 906-910
Author(s):  
Hui Ru Liu ◽  
Li Qiang Lv ◽  
Xing Chen Zhang
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Melting Point ◽  
Quantum Chemical ◽  
Organic Molecules ◽  
Raw Materials ◽  
Ammonium Thiocyanate ◽  
Molar Ratio ◽  
Molecular Ion

This study concerned a novel super-molecular ionic liquid synthesized by ammonium thiocyanate and caprolactam. The physical characters such as melting point and electric conductivity were investigated. Results showed that the melting point is -12.2°C at the molar ratio of 3:1 (caprolactam/ammonium thiocyanate), which is much lower than raw materials. The electric conductivities of synthesized ionic liquids were close to that of imidazole ILs. The structure of ionic liquid was characterized by IR,1HNMR and quantum chemical calculations. It was shown that the NH4+cation connected with caprolactam organic molecules by hydrogen bonds, leading to the forming of a super-molecular ion. The electrostatic attraction of super-molecular ion with anion was decreased because of the larger volume of super-molecular ion than original cation, thus the melting point decreased. The key properties that distinguish super-molecular ionic liquid from other ILs were the presence of supermolecular ion, which can be used to build up a hydrogen-bonded network. This type ion liquid was named as super-molecular ion liquid.

Novel Ionic Liquid Lubricants for Aerospace and MEMS

2005 ◽  
Author(s):  
Barbara J. Kinzig ◽  
Paul Sutor ◽  
Gregory W. Sawyer ◽  
Alison Rennie ◽  
Pamela Dickrell ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Molten Salts ◽  
Room Temperature ◽  
Room Temperature Ionic Liquids ◽  
Melting Points

Room temperature ionic liquids (RTILs) are molten salts with melting points at or below room temperature. RTILs have recently been recognized as novel lubricants. Only a few have previously been evaluated.

scholarly journals Tuning the melting point of selected ionic liquids through adjustment of the cation's dipole moment

2020 ◽  
Vol 22 (21) ◽  
pp. 12301-12311 ◽  
Author(s):  
Brooks D. Rabideau ◽  
Mohammad Soltani ◽  
Rome A. Parker ◽  
Benjamin Siu ◽  
E. Alan Salter ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Dipole Moment ◽  
Melting Point ◽  
Fluorine Substitution

Adjusting the dipole moment of an ionic liquid cation through fluorine substitution for hydrogen tunes the melting point.

Physical Properties of Substituted Imidazolium Based Ionic Liquids Gel Electrolytes

2002 ◽  
Vol 57 (11) ◽  
pp. 839-846 ◽  
Author(s):  
Thomas E. Sutto ◽  
Hugh C. De Long ◽  
Paul C. Trulove
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Ionic Conductivity ◽  
Physical Properties ◽  
Molten Salt ◽  
Polyacrylic Acid ◽  
Molten Salts ◽  
Polymer Gel ◽  
Composite Gels ◽  
Gel Electrolytes

The physical properties of solid gel electrolytes of either polyvinylidene diflurohexafluoropropylene or a combination of polyvinylidene hexafluoropropylene and polyacrylic acid, and the molten salts 1-ethyl-3-methylimidazolium tetrafluoroborate, 1,2-dimethyl-3-n-propylimidazolium tetrafluoroborate, and the new molten salts 1,2-dimethyl-3-n-butylimidazolium tetrafluoroborate, and 1,2-dimethyl-3-n-butylimidazolium hexafluorophosphate were characterized by temperature dependent ionic conductivity measurements for both the pure molten salt and of the molten salt with 0.5 M Li+ present. Ionic conductivity data indicate that for each of the molten salts, the highest concentration of molten salt allowable in a single component polymer gel was 85%, while gels composed of 90%molten salt were possible when using both polyvinylidene hexafluorophosphate and polyacrylic acid. For polymer gel composites prepared using lithium containing ionic liquids, the optimum polymer gel composite consisted of 85% of the 0.5 M Li+/ionic liquid, 12.75% polyvinylidene hexafluoropropylene, and 2.25% poly (1-carboxyethylene). The highest ionic conductivity observed was for the gel containing 90%1-ethyl-3-methyl-imidazolium tetrafluoroborate, 9.08 mS/cm. For the lithium containing ionic liquid gels, their ionic conductivity ranged from 1.45 to 0.05 mS/cm, which is comparable to the value of 0.91 mS/cm, observed for polymer composite gels containing 0.5 M LiBF4 in propylene carbonate.

scholarly journals Azoniaspiro salts: towards bridging the gap between room-temperature ionic liquids and molten salts

2016 ◽  
Vol 18 (4) ◽  
pp. 3339-3351 ◽  
Author(s):  
Matthew T. Clough ◽  
Karolin Geyer ◽  
Patricia A. Hunt ◽  
Alastair J. S. McIntosh ◽  
Rebecca Rowe ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Molten Salts ◽  
Room Temperature ◽  
Room Temperature Ionic Liquids ◽  
Thermal Stabilities ◽  
Chloride Salts

Organic spirocyclic tetraalkylammonium chloride salts exhibit enhanced thermal stabilities relative to traditional dialkylimidazolium ionic liquid analogues.

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