Fusion properties of some ionic quaternary ammonium compounds

Coker, T. G.; Ambrose, J.; Janz, George J.

doi:10.1021/ja00721a001

Cited by 83 publications

(44 citation statements)

References 4 publications

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“…In the liquid state, the sample may reside in the periphery of the crucible due to surface tension. If a ther- [157] 158-159; [158] 164-165; [159] 166 [160] [ mal gradient between the center and the circumference of the crucible exists, slightly different T fus may be obtained. [75] Especially if high melting temperatures are expected, the use of a crucible with an opening is advisable to avoid the influence of pressure.…”

Section: Recommendations For Dsc Measurementsmentioning

confidence: 99%

Is Universal, Simple Melting Point Prediction Possible?

et al. 2011

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An investigation of the melting points of 520 organic 1:1 salts is presented with the aim of developing a universal, simple, physically well-founded prediction scheme. The general reliability and reproducibility of the recorded experimental data are discussed with respect to purity, phase behavior, disorder and thermal history of a given substance. Additionally, mistakes, systematic errors, or lack of conventions can lead to considerable differences in the experimental measurements. A rough error bar for the reproducibility of the melting points of organic salts of ±5 to ±15 °C can be assigned. With this restraint, we developed two simple, semiempirical, five- and nine-parameter schemes with easy-to-calculate quantities. With these, we could predict the melting temperature of a given organic salt in the temperature range of -25 to +300 °C with an average error of 33.5 °C and a relative error of 9.3%. All calculated quantities are assessed with the help of conventional DFT, COSMO and COSMO-RS calculations, and are currently implemented into the IL-Prop module of the upcoming version of COSMOtherm. These prediction schemes are suitable for high-throughput computational screening of substances in the context of "computer-aided synthesis". Therefore, they are valuable tools to find a compound with a suitable melting point before its first synthesis.

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Section: Recommendations For Dsc Measurementsmentioning

confidence: 99%

Is Universal, Simple Melting Point Prediction Possible?

et al. 2011

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“…In addition, tetra-nheptylammonium nitrate was investigated to confirm the rather unusual results reported for several other tetrasubstituted salts [5]. The results are listed in the A previous investigation of monosubstituted n-alkylammonium halides showed that the entropies of fusion were less than 5 e.u.…”

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confidence: 57%

“…However, the existence of several solid-solid transitions in these compounds have been previously established [4][5][6][7]. It would seem that tJ~e crystal and molecular structure of the solid phase existing closest to the melting points (Phase l) should be used as the basis for any comparisons between the solid and molten or solution phases.…”

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confidence: 99%

A differential scanning calorimetric study of phase transitions in polysubstitutedn-alkylammonium halides

Lippman

Rudman

1976

Journal of Thermal Analysis

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A DSC investigation of several n-alkylammonium salts is reported. The results of this investigation can be used to help decide which of several crystalline forms should be studied by X-ray diffraction for the best correlation between the liquid and solid states.The n-alkylammonium halide compounds are currently under intensive investigation for a number of reasons. For example, the quaternary salts are excellent cationic detergents when dissolved in hydrocarbons; their concentrated solutions are known as liquid membranes (and are believed to control a large number of biological processes, with their bioactivity being a function of the structure of the solute); and they are pharmacologically active substances [1]. The secondary salts are widely used in solvent extraction processes in general and in the extraction of fused salts in particular [2].During the course of these investigations, attempts have been made to correlate the properties of these materials in solution and in the molten state with the structure in the solid state [2,3]. However, the existence of several solid-solid transitions in these compounds have been previously established [4][5][6][7]. It would seem that tJ~e crystal and molecular structure of the solid phase existing closest to the melting points (Phase l) should be used as the basis for any comparisons between the solid and molten or solution phases. However, if the structural differences between Phase I and the room-temperature phase are minor, then a reasonable and more practical approach would be to base the comparison on the room-temperature phase.As a first step in making this decision, the temperatures of the phase transitions and several thermodynamic parameters should be obtained. This information will be helpful in selecting proper temperature ranges for the crystal structure analyses and in predicting the degree of disorder to be expected in the high-temperature phases.Enthalpies and entropies of transition and of fusion, as well as the transition and fusion temperatures, have been reported for a number of substituted n-alkyl-

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“…The uncertainty in density measurements was determined to be 0.00125 g cm -3 . The molarity of solutions was converted to molality using standard expressions [18][19][20][21] and density values. The ultrasonic velocity of solutions were measured with ultrasonic interferometer, model-M-84 (Mittal Enterprises, India,) with a frequency of 2 MHz.…”

Section: Methodsmentioning

confidence: 99%

Ultrasonic Studies on Ion-Solvent Interactions of Tetra-n-butylammonium Bromide in Aqueous Solution of 1,3-Dioxolane and 2,2-Dimethoxypropane at Different Temperatures

Sarangi¹,

Panda²,

Sahu³

et al. 2018

Asian J. Chem.

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Tetra-n-butylammonium bromide (TBAB) is made soluble in different solvents like 10 % 1,3-dioxolane-water and 10 % dimethoxypropanewater. Ultrasonic velocity (U), density (ρ) and coefficient of viscosity (η) are determined at different temperatures i.e. at 298.15, 303.15, 308.15 and 313.15 K. These values of ultrasonic velocity (U), density (ρ) and co-efficient of viscosity (η) are used to calculate the thermo acoustic properties like isentropic compressibility (βs), molar compressibility (W), acoustic impedance (Z), molar sound velocity (R), relative association (RA), intermolecular free length (Lf), free volume (Vf), internal pressure (πi), isothermal compressibility (βT). The results obtained were analyzed to interpret the ion-ion and ion-solvent interactions occurring in the solutions.

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Fusion properties of some ionic quaternary ammonium compounds

Abstract: Enthalpy, entropy, and molar volume changes during the fusion process of a wide range of quaternary

Cited by 83 publications

References 4 publications

Is Universal, Simple Melting Point Prediction Possible?

Is Universal, Simple Melting Point Prediction Possible?

A differential scanning calorimetric study of phase transitions in polysubstitutedn-alkylammonium halides

Ultrasonic Studies on Ion-Solvent Interactions of Tetra-n-butylammonium Bromide in Aqueous Solution of 1,3-Dioxolane and 2,2-Dimethoxypropane at Different Temperatures

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