scholarly journals Apparent molar heat capacities and volumes of alkylbenzenesulfonate salts in water: substituent group additivity

1986 ◽  
Vol 64 (2) ◽  
pp. 394-398 ◽  
Author(s):  
K. Sway ◽  
Jamey K. Hovey ◽  
Peter R. Tremaine
Keyword(s):  
Alkyl Chain ◽  
Partial Molar Volumes ◽  
Heat Capacities ◽  
Group Additivity ◽  
Apparent Molar Heat Capacities ◽  
Sodium Salts ◽  
Aqueous Sodium ◽  
Specific Heats ◽  
Polar Groups ◽  
Substituent Group

Densities and specific heats were measured for the aqueous sodium salts of benzenesulfonate, p-toluenesulfonate, 2,4- and 2,5-dimethylbenzenesulfonate, mesitylenesulfonate, and p-ethylbenzenesulfonate. The limiting partial molar volumes, [Formula: see text] and heat capacities, [Formula: see text], lead to revised values in the group contributions for aromatic —CH2— and —CH3 groups in the additivity scheme proposed by Perron and Desnoyers. The heat capacities of substituted alkylbenzenes can deviate from group additivity by as much as 70 and 40 J K−1 mol,−1, respectively, when polar groups are located on the α and β positions of the alkyl chain.

Apparent molar heat capacities and volumes of aqueous sodium propionate

1984 ◽  
Vol 81 ◽  
pp. 381-384 ◽  
Author(s):  
Jarl B. Rosenholm ◽  
Loren G. Hepler
Keyword(s):  
Heat Capacities ◽  
Sodium Propionate ◽  
Apparent Molar Heat Capacities ◽  
Aqueous Sodium

Densities and apparent molar volumes of aqueous aluminum chloride. Analysis of apparent molar volumes and heat capacities of aqueous aluminum salts in terms of the Pitzer and Helgeson theoretical models

1986 ◽  
Vol 64 (2) ◽  
pp. 353-359 ◽  
Author(s):  
Leslie Barta ◽  
Loren G. Hepler
Keyword(s):  
Aqueous Solutions ◽  
Interaction Model ◽  
Partial Molar Volumes ◽  
Theoretical Models ◽  
Heat Capacities ◽  
Apparent Molar Volumes ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes ◽  
Aqueous Aluminum

Densities of aqueous solutions of AlCl3 (containing dilute HCl) have been measured at 10, 25, 40, and 55 °C with results that have led to defined apparent molar volumes. We have used the Pitzer ion interaction model as the basis for analyzing these apparent molar volumes to obtain standard state (infinite dilution) partial molar volumes of AlCl3(aq) at each temperature. We have also made similar use of apparent molar heat capacities of aqueous solutions of AlCl3–HCl and Al(NO3)3–HNO3 from Hovey and Tremaine to obtain standard state partial molar heat capacities of AlCl3(aq) and Al(NO3)3(aq) at these same temperatures. Finally, the standard state partial molar volumes and heat capacities have been used with the Helgeson–Kirkham semi-theoretical equation of state for aqueous ions to provide a basis for estimating the thermodynamic properties of Al3+(aq) at high temperatures and pressures.

Apparent molar heat capacities and volumes of unsaturated heterocyclic solutes in aqueous solution at 25 °C

1980 ◽  
Vol 58 (7) ◽  
pp. 704-707 ◽  
Author(s):  
Octavian Enea ◽  
Carmel Jolicoeur ◽  
Loren G. Hepler
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Heterocyclic Compounds ◽  
Infinite Dilution ◽  
Heat Capacities ◽  
Group Additivity ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Partial Molar Heat Capacities

Measurements at 25 °C with flow calorimeters and densimeters have led to heat capacities and densities of aqueous solutions of 15 unsaturated heterocyclic compounds containing nitrogen. From the results of these measurements we have obtained apparent molar heat capacities and volumes of the solutes. Extrapolations to infinite dilution have led to corresponding standard state apparent and partial molar heat capacities and volumes, which have been analyzed in terms of atomic and group additivity relationships.

Thermodynamic properties of aqueous diethanolamine (DEA), N,N-dimethylethanolamine (DMEA), and their chloride salts: apparent molar heat capacities and volumes at temperatures from 283.15 to 328.15 K

2000 ◽  
Vol 78 (1) ◽  
pp. 151-165 ◽  
Author(s):  
Christopher Collins ◽  
Joelle Tobin ◽  
Dmitri Shvedov ◽  
Rom Palepu ◽  
Peter R Tremaine
Keyword(s):  
Partial Molar Volumes ◽  
Heat Capacities ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes ◽  
Partial Molar Heat Capacities ◽  
Relaxation Effects ◽  
Chemical Relaxation ◽  
Young's Rule ◽  
Vibrating Tube Densimeter ◽  
Chloride Salts

Apparent molar heat capacities Cp,ϕ and apparent molar volumes Vϕ for aqueous diethanolamine (HOC2H4)2NH, diethanolammonium chloride (HOC2H4)2NH2Cl, N,N'-dimethylethanolamine (HOC2H4)(CH3)2N, and N,N'-dimethylethanolammonium chloride (HOC2H4)(CH3)2NHCl were determined from 283.15 to 328.15 K with a Picker flow microcalorimeter and vibrating tube densimeter. The experimental results have been analyzed in terms of Young's Rule with the Guggenheim form of the extended Debye-Hückel equation and appropriate corrections for chemical relaxation effects. These calculations lead to standard partial molar heat capacities and volumes for the neutral amines, (HOC2H4)2NH(aq) and (HOC2H4)(CH3)2N(aq), and the ions (HOC2H4)2NH2+(aq) and (HOC2H4)(CH3)2NH+(aq) over the experimental temperature range. Key words: standard partial molar volumes, standard partial molar heat capacities, diethanolamine, dimethyethanolamine, aqueous alkanolamine ionization.

The volumetric and thermochemical properties of L-ascorbic acid in water at 288.15, 298.15, and 308.15 K

1993 ◽  
Vol 71 (7) ◽  
pp. 925-929 ◽  
Author(s):  
Andrew W. Hakin ◽  
Susan A. M. Mudrack ◽  
Colin L. Beswick
Keyword(s):  
Heat Capacity ◽  
Ascorbic Acid ◽  
Sodium Chloride ◽  
Heat Capacities ◽  
Thermochemical Data ◽  
Thermochemical Properties ◽  
Apparent Molar Heat Capacities ◽  
Sodium Salts ◽  
Molar Volumes ◽  
Volume Of Ionization

Measurements have been made at 288.15, 298.15, and 308.15 K with a flow microcalorimeter and densimeter to obtain heat capacities and densities for L-ascorbic acid and sodium chloride in water. These data are reported in terms of apparent molar volumes [Formula: see text] and apparent molar heat capacities [Formula: see text] The volume of ionization (ΔV0) and heat capacity of ionization (ΔCP0) for the acid at 298.15 K have been calculated using a method that does not require volumetric and thermochemical data for the sodium salts of the acid. Details of our methodology are presented.

Calorimetric investigations of aqueous amino acid and dipeptide systems from 288. 15 to 328. 15 K

1995 ◽  
Vol 73 (5) ◽  
pp. 725-734 ◽  
Author(s):  
Andrew W. Hakin ◽  
Michelle M. Duke ◽  
Lori L. Groft ◽  
Jocelyn L. Marty ◽  
Matthew L. Rushfeldt
Keyword(s):  
Amino Acid ◽  
Thermodynamic Properties ◽  
Heat Capacities ◽  
Group Additivity ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Empirical Modelling ◽  
Temperature Dependences ◽  
Calorimetric Investigations ◽  
Capacity Data

Densities and heat capacities have been measured for aqueous solutions of L-asparagine, L-glutamine, glycylglycine, glycyl-L-valine, glycyl-L-asparagine, and glycyl-DL-leucine at 288.15, 298.15, 313.15, and 328.15 K. These data have been used to calculate apparent molar volumes, V2,ø, and apparent molar heat capacities, Cp,2,ø, which in turn have been used to obtain standard state volumes, [Formula: see text] and heat capacities, [Formula: see text] The semi-empirical modelling procedures of Helgeson, Kirkham, and Flowers have been used to subdivide the calculated standard state volume and heat capacity data into solvation and nonsolvation contributions. The nonsolvation components of the standard state properties are used in group additivity analyses. These analyses yield structural contributions to standard state volumes and heat capacities for the CH(NH2)CO2H, CH2, OH, COOH, CH, CONH2, and CONH groups. The temperature dependences of these contributions are discussed. Some comments are reported concerning the practicality of using the thermodynamic properties of aqueous amino acid and peptide systems as the basis for modelling standard state thermodynamic properties of aqueous protein systems. Keywords: heat capacities, densities, volumes, amino acids, peptides, group additivity.

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