Partial molal heat capacities of aqueous tetraalkylammonium bromides as functions of temperature

Shin, Charles; Worsley, Ian G.; Criss, Cecil M.

doi:10.1007/bf01167240

Cited by 23 publications

(7 citation statements)

References 27 publications

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“…Another difficulty rests with the tetraalkyammonium ions that are also not well correlated through eq 4. Heat capacities in water for the tetraalkylammonium ions indicate that as the alkyl groups become larger, these ions become more and more hydrophobic structure-making ions. ,, Such behavior cannot be accounted for by the descriptors used for nonelectrolytes, eq 4, and so we introduce another term, j + . J + in the equation, specifically to take the tetraalkylammonium ions into account.…”

Section: Resultsmentioning

confidence: 99%

“…The J + descriptor for cations seems to be related to structural effects of the ions. A plot of partial molal heat capacities in water 52 against J + shows that as structural effects such as hydrophobic hydration increase for the tetraalkylammonium ions, so does J + increase, Figure . Shin et al showed that a plot of partial molar heat capacities in water against cation radius was similar in shape to that in Figure , so that it is no surprise to find that J + itself correlates with ionic radius (Figure ); this might be useful in assigning values of J + for other cations.…”

Section: Resultsmentioning

confidence: 99%

“…As mentioned above in discussions on single ion transfers, it is considered that the transfer energy for the tetraphenyl ions is due to a “neutral” part and an “electrostatic” part, the latter being mainly ion−dipole with some ion−quadropole character. − It has never been considered that the presence of the aromatic rings can lead to an effect such as hydrogen bond basicity. Even if the central ion is shielded from the solvent, this does not apply to the four phenyl groups.…”

Section: Resultsmentioning

confidence: 99%

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Determination of Solvation Descriptors for Ionic Species: Hydrogen Bond Acidity and Basicity

Abraham

Zhao

2004

J. Org. Chem.

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Literature values of Gibbs energies of transfer of ions from water to other solvents have been used in conjunction with our solvation equation to obtain descriptors for univalent ions. It is suggested that descriptors used for nonelectrolytes are not adequate to describe transfers of single ions, and that two specific ionic descriptors (J(+) and J(-)) for cations and anions, respectively, are required. The ions studied include the alkali metal and tetraalkylammonium cations, halide and other anions, and the tetraphenylarsonium, tetraphenylphosphonium, and tetraphenylborate ions. It is shown that simple cations such as Na(+) act as very strong hydrogen bond acids and that the R(4)N(+) ions are only weak hydrogen bond acids. The halide anions are very strong hydrogen bond bases, as is also the acetate anion. Other anions, such as azide, cyanide, and nitrate, are again very strong hydrogen bond bases. The tetraphenylarsonium, tetraphenylphosphonium, and tetraphenylborate ions have no hydrogen bond acidity but are quite strong hydrogen bond bases. It is suggested that this is due to the basic properties of the phenyl groups.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Determination of Solvation Descriptors for Ionic Species: Hydrogen Bond Acidity and Basicity

Abraham

Zhao

2004

J. Org. Chem.

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“…De nombreux auteurs [39,43] Selon Desnoyers [43] les quantités molaires apparentes standard se subdivisent en quatre contributions distinctes. Ainsi la capacité calorifique molaire apparente standard peut s'écrire : …”

Section: -5 Les Interactions Soluté-solvantunclassified

Thermodynamique des systèmes micellaires Partie III : Capacités calorifiques apparente et partielle des alcanoates de sodium

Hajji¹

2010

Afrique Science: Revue Internationale Des Sciences Et Technologie

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Thermodynamics of micellar systems Part III : Apparent and partial heat capacities of sodium alkanoatesTo obtain the heat capacities of the aqueous solutions of the sodium carboxylates, we carry out microcalorimetric heat capacities measurements. The aim of this work is to calculate the quantities of the apparent and partial molar heat capacities, and also to define the critical micellar concentrations. The variations of the partial molar heat capacities by increment -CH2 allows us to give prove for products supposed to form true Afrique SCIENCE 03(2) (2007) 214 -231 M. Said HAJJI 215 micelles and products do not form micelles. To discuss the solute-solvent and solutesolute interactions we used the standard apparent molar heat capacities.

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“…To calculate these characteris tics from the temperature dependences of solution enthalpies, it is necessary to know the heat capacities of crystalline salts. Despite numerous studies ( [5][6][7][8][9]), however, no data are available for salts with more than five carbon atoms in the alkyl chain (C 6 , C 7 , etc. ).…”

Section: Introductionmentioning

confidence: 99%

Heat capacities of crystalline tetraalkylammonium salts

Manin

Кустов

Антонова

2012

Russ. J. Phys. Chem.

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The behavior of crystalline tetraalkylammonium salts at 290-350 K was studied by differential scanning calorimetry. For tetraethyl and tetrabutylammonium bromides (Et 4 NBr and Bu 4 NBr), the exper imental heat capacities agreed well with the literature values. For tetrahexyl , tetraheptyl , and tetraoctylam monium bromides (Hex 4 NBr, Hep 4 NBr, and Oct 4 NBr), phase transitions were found between crystal mod ifications whose characteristic temperatures depended significantly on the size of the cation. Empirical equa tions for the temperature dependences of the heat capacities of the salts within the ranges of homogeneous equilibrium phases were derived.

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Partial molal heat capacities of aqueous tetraalkylammonium bromides as functions of temperature

Cited by 23 publications

References 27 publications

Determination of Solvation Descriptors for Ionic Species: Hydrogen Bond Acidity and Basicity

Determination of Solvation Descriptors for Ionic Species: Hydrogen Bond Acidity and Basicity

Thermodynamique des systèmes micellaires Partie III : Capacités calorifiques apparente et partielle des alcanoates de sodium

Heat capacities of crystalline tetraalkylammonium salts

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