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Chemical Properties

Yellowish-beige crystalline coarse crystals

Upstream product

• 110-86-1 pyridine 
• 111-25-1 1-bromo-hexane 

Relevant academic research and scientific papers

Physicochemical properties of ionic liquids [C3py][NTf 2] and [C6py][NTf2]

Air- and water-stable hydrophobic ionic liquids N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([Cnpy][NTf2], n = 3, 6) were synthesized. The density, surface tension, dynamic viscosity, and electrical conductivity of [C6py][NTf2] were measured in the range of T = (283.15 to 338.15) K. The density, dynamic viscosity, and electrical conductivity of [C3py][NTf2] were measured in the range of T = (308.15 to 338.15) K. The melting and glass transition temperatures of the two ILs were determined according to the differential scanning calorimetry (DSC). The physicochemical properties, including molecular volume, standard molar entropy, lattice energy, parachor, molar enthalpy of vaporization, interstice volume, interstice fraction, and thermal expansion coefficient, were estimated in terms of empirical and semiempirical equations, as well as the interstice model theory on the base of the experimental values. The dynamic viscosity and electrical conductivity values were fitted by Vogel-Fulcher-Tammann (VFT) and Arrhenius equations for [C6py] [NTf2] and the Arrhenius equation for [C3py][NTf 2].

Properties of Bromine Fused Salts Based on Quaternary Ammonium Molecules and Their Relevance for Use in a Hydrogen Bromine Redox Flow Battery

Bromine complexing agents (BCA) in aqueous electrolytes for hydrogen bromine flow batteries are used to reduce bromine‘s vapour pressure, while an insoluble and liquid fused salt is formed. The properties (concentrations, composition, conductivity and viscosity) of this fused salt are investigated in this study systematically ex situ by using 7 BCAs at different state of charge in HBr/Br2/H2O electrolytes with a theoretical capacity of 179.6 Ah L?1. Bromine is stored in the fused salt at concentrations up to 13.6 M, reaching theoretical volumetrical capacities up to 730 Ah L?1 in fused salts. The fused salt consists of a pure, bromine- and water-free ionic liquid of organic [BCA]+ cations and polybromides, and its conductivity bases on a hopping mechanism among the polybromides. Alkyl side chain length of the BCAs and distribution of polybromides influence strongly the conductivity and viscosity of the fused salts. 1-ethylpyridin-1-iumbromide results to be favoured BCA for application.

ZIF-8-porous ionic liquids for the extraction of 2,2,3,3-tetrafluoro-1-propanol and water mixture

The design of stable ionic liquids (ILs) has become crucial for efficient liquid-liquid extraction (LLE) of alcohol and water. Porous ionic liquids (PILs), as a special class of ILs, have attracted attention by virtue of their unique porous structure and IL characteristics. In this research, a series of zeolitic imidazolate framework-8 based porous ionic liquids (ZIF-8-PILs) were synthesized by simply mixing a solution of zeolitic imidazolate framework-8 (ZIF-8) and rationally designed ILs. The introduction of ZIF-8 resulted in a unique liquid porous structure and molecular sieve for ZIF-8-PILs. The improved extraction properties endowed ZIF-8/[Bpy][NTf2] with more efficiency for the separation of 2,2,3,3-tetrafluoro-1-propanol (TFP) and water with 88.1% TFP extraction rate and steady reuse. The excellent extraction performance of ZIF-8-PILs is discussed in relation to their textural property and unique intermolecular interaction.

Micelle formation as a factor influencing the mode(s) of metal ion partitioning into: N -alkylpyridinium-based ionic liquids (ILs): Implications for the design of IL-based extraction systems

Prior studies of metal ion partitioning between an acidic aqueous phase and an ionic liquid in the presence of a macrocyclic polyether have demonstrated that the overall partitioning is a composite of three distinct pathways: neutral complex/ion-pair extraction, exchange of a cationic metal-crown ether (CE) complex for the cationic constituent of the IL, and exchange of the metal ion for a hydronium ion in a CE-H3O+ complex formed during acid preconditioning of the IL. The obvious undesirability of the ion-exchange pathways, which can lead to substantial loss of the IL cation to the aqueous phase, has led to efforts to identify means by which these processes can be suppressed or eliminated. Prior work with N,N′-dialkylimidazolium and quaternary ammonium bis [(trifluoromethyl)sulfonyl]imides has shown that increasing the hydrophobicity of the IL cation can be an effective means of diminishing the contribution of ion-exchange. Work with the corresponding N-alkylpyridinium ILs, however, indicates that in certain instances, an increase in the hydrophobicity of the IL cation is accompanied by a marked increase in its propensity to self-associate, leading to the formation of micelles in the aqueous phase. The net effect is to diminish or even negate the expected beneficial effect of IL cation hydrophobicity in reducing the contribution of ion exchange to the overall metal ion partitioning process, adversely impacting the "greenness" of extraction processes employing these ILs.

Ultrafast dynamics in aromatic cation based ionic liquids: A femtosecond raman-induced kerr effect spectroscopic study

We studied the ultrafast dynamics of 40 aromatic cation based ionic liquids (ILs) by means of femtosecond Ramaninduced Kerr effect spectroscopy. The low-frequency Kerr spectra (ca. 0.3700 cm1) of the ILs were obtained from the Kerr transients by Fourier-Transform deconvolution analysis. The low-frequency Kerr spectra in the frequency range less than 200 cm-1 coming mainly from the intermolecular vibrations for the ILs were discussed in terms of (i) anion dependence, (ii) imidazolium cations vs. pyridinium cations, (iii) alkyl group dependence, and (iv) effect of methylation in aromatic cations. Several liquid properties, such as density, viscosity, electrical conductivity, and surface tension, of the present sample ILs at 293K were also estimated in this study. We clarified that the aromatic cation based ILs show a different relation of the first moment of the low-frequency spectral band to the bulk liquid parameter, which is the square root of surface tension divided by liquid density, from aprotic molecular liquids. The slope of the first moment to the bulk parameter for the aromatic cation based ILs is gentler than that for aprotic molecular liquids.

Octanol/water partition coefficients of pyridinium-based ionic liquids

Nine pyridinium-based ionic liquids were synthesised, which include 1-butylpyridinium bromide ([BPYR] [Br]), 1-hexylpyridinium bromide ([HPYR][Br]), 1-octylpyridinium bromide ([OPYR][Br]), 1-hexylpyridinium bis(trifluoromethylsulfonyl)imide ([HPYR] [NTf2]), 1-octylpyridinium bis(trifluoromethylsulfonyl)imide ([OPYR][NTf2]), 1-hexylpyridinium trifluoromethanesulfonate ([HPYR] [TFO]), 1-octylpyridinium trifluoromethanesulfonate ([OPYR][TFO]), 1-hexylpyridinium tetrafluoroborate ([HPYR] [BF4]), 1-octylpyridinium I tetrafluoroborate ([OPYR][BF4]). The octanol/water partition coefficients (KOWs) of these pyridinium-based ionic liquids were determined by shake-flask method. It is found that the pyridinium-based ionic liquids measured in this work are extremely hydrophilic except for [OPYR] [NTf2]. It is also found that KOWs of [NTf2] ionic liquids were dependent on the concentration and high ionic liquids concentration in water leads to big KOW.

Thermochemistry of the pyridinium- and pyrrolidinium-based ionic liquids

We applied DSC for the determination of enthalpies of synthesis reactions of pyridinium- and pyrrolidinium-based ionic liquids (ILs) from pyridine (or N-methyl-pyrrolidine) and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of enthalpies of the formation and vaporization enthalpies of ILs.

Does alkyl chain length really matter? Structure-property relationships in thermochemistry of ionic liquids

DSC was used for determination of reaction enthalpies of synthesis of ionic liquids [Cnmim][Cl]. A combination of DSC with quantum chemical calculations presents an indirect way to study thermodynamics of ionic liquids. The indirect procedure for vaporization enthalpy was validated with the direct experimental measurements by using thermogravimetry. First-principles calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the CBS-QB3 and G3 (MP2) theory. Experimental DSC data for homologous series of alkyl substituted imidazolium, pyridinium, and pyrrolidinium based ionic liquids with anions [Cl] and [Br] were collected from the literature. We have shown that enthalpies of formation, enthalpies of vaporization, and lattice potential energies are linearly dependant on the alkyl chain length. The thermochemical properties of ILs generally obey the group additivity rules and the values of the additivity parameters for enthalpies of formation and vaporization seem to be very close to those for molecular compounds.

Three different types of heterocycle of nitrogen-containing alkaline ionic liquids treatment of acid oil to remove naphthenic acids

Ionic liquids had enormous potential for industrial use as environmental friendly chemicals. A green and effective deacidification method was found based on ionic liquids. N-alkylpyridinium bromide ([APy]Br), 1-alkyl-3- methylimidazolium bromide ([AMIm]Br) and 1-alkyl-3-methylimidazolium imidazolide ([AMIm]Im) were used to remove naphthenic acids from acid oil. The performance of deacidification followed the order [APy]Br [AMIm]Br [AMIm]Im. The stronger alkalinity of ionic liquids was, the higher deacidification would be. The growth of alkyl chain length was also beneficial to get high deacidification. The deacidification mechanism was that liquid clathrate could form due to interaction between the ionic liquids and π-bond in naphthenic acids through π-π interaction. When the reagent/oil ratio of [OMIm]Im (1-octyl-3-methylimidazolium imidazolide)/oil was 0.008, the deacidification rate could be reached 100%. The preliminary results reveal that the process consumes less energy, saves time and produces less pollution to environment.

Scalable synthesis of ionic liquids: Comparison of performances of microstructured and stirred batch reactors

A range of alkylpyridinium bromide ionic liquids have been synthesized in a stirred reactor at multigram scale and characterized by physical methods (viscosity, conductivity, melting point, electrochemical window, and water content). One ionic liquid, octylpyridinium bromide, was chosen to be synthesized in both macro and reduced scale reactors, in order to compare its performance and to afford evidence of the advantages of a cross channel micro reactor (channel width = 1 mm) compared to a stirred reactor.