- Novel ionic liquid with peroxyniobate-radical negative ions and preparing method thereof
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The invention relates to novel ionic liquid with peroxyniobate-radical negative ions and a preparing method thereof. The ionic liquid comprises imidazolium salt positive ions, quaternary ammonium salt positive ions and the peroxyniobate-radical negative ions. The preparing method of the ionic liquid includes the steps that 1, alkyl-replacing N-methylimidazole hydrochloride is prepared from N-methylimidazole; 2, alkyllimidazolium salt chloride and quaternary ammonium salt halogenide are subjected to ion exchange to obtain corresponding ethanol solutions of hydroxide; 3, ammonium peroxyniobate is prepared from commercial niobium pentoxide with the document method; 4, the brand-new-structure ionic liquid with the peroxyniobate-radical negative ions is obtained with the ion exchange (acid-base neutralization) method. According to the novel ionic liquid with the peroxyniobate-radical negative ions and the preparing method thereof, the ionic liquid is prepared for the first time, the preparing method is simple, the yield is high, and the characteristics of a niobium element can be fully used to carry out a certain catalytic oxidation reaction.
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Page/Page column 6; 7
(2016/12/01)
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- Influence of alkyl chain length and temperature on thermophysical properties of ammonium-based ionic liquids with molecular solvent
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Mixing of ionic liquids (ILs) with molecular solvent can expand the range of structural properties and the scope of molecular interactions between the molecules of the solvents. Exploiting of these phenomena essentially require a basic fundamental understanding of mixing behavior of ILs with molecular solvents. In this context, a series of protic ILs possessing tetra-alkyl ammonium cation [R4N]+ with commonly used anion hydroxide [OH]- were synthesized and characterized by temperature dependent thermophysical properties. The ILs [R4N]+[OH]- are varying only in the length of alkyl chain (R is methyl, ethyl, propyl, or butyl) of tetra-alkyl ammonium on the cationic part. The ILs used for the present study included tetramethyl ammonium hydroxide [(CH3) 4N]+[OH]- (TMAH), tetraethyl ammonium hydroxide [(C2H5)4N]+[OH]- (TEAH), tetrapropyl ammonium hydroxide [(C3H7)4N] +[OH]- (TPAH) and tetrabutyl ammonium hydroxide [(C 4H9)4N]+[OH]- (TBAH). The alkyl chain length effect has been analyzed by precise measurements such as densities (ρ), ultrasonic sound velocity (u), and viscosity (η) of these ILs with polar solvent, N-methyl-2-pyrrolidone (NMP), over the full composition range as a function of temperature. The excess molar volume (VE), the deviation in isentropic compressibility (Δκs) and deviation in viscosity (Δη) were predicted using these properties as a function of the concentration of ILs. Redlich-Kister polynomial was used to correlate the results. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and NMP molecules. Later, the hydrogen bonding features between ILs and NMP were also analyzed using a molecular modeling program with the help of HyperChem 7.
- Kavitha,Attri, Pankaj,Venkatesu, Pannuru,Devi, R. S. Rama,Hofman
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experimental part
p. 4561 - 4574
(2012/07/02)
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- Temperature effect on the molecular interactions between ammonium ionic liquids and N, N-dimethylformamide
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In view of the wide scope of molecular interactions between the highly polar compound of N,N-dimethylformamide (DMF) and ammonium ionic liquids (ILs), we have measured thermophysical properties such as densities (??) and ultrasonic sound velocities (u) over the whole composition range at temperatures ranging from 25 to 50 ?°C under atmospheric pressure. To gain some insight into the several aggregations of molecular interactions present in these mixed solvents, we predicted the excess molar volume (VE) and the deviations in isentropic compressibilities (??Ks) as a function of the concentration of IL. These results are fitted to the Redlich-Kister polynomials. The materials investigated in the present study included the hydroxide series of ammonium ILs of tetramethylammonium hydroxide [(CH 3)4N][OH] (TMAH), tetraethylammonium hydroxide [(C 2H5)4N][OH] (TEAH), and tetrapropylammonium hydroxide [(C2H7)4N][OH] (TPAH). The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion-dipole and ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors. ? 2010 American Chemical Society.
- Attri, Pankaj,Venkatesu, Pannuru,Kumar, Anil
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experimental part
p. 13415 - 13425
(2011/02/18)
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