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1.
Fujisawa M. Maeda M. Takagi S. Kimura T. 《Journal of Thermal Analysis and Calorimetry》2002,69(3):841-848
The enthalpies of dilution of aqueous solutions of methanol, ethanol, l-propanol, 2-propanol, 1-butanol, l-pentanol, 1-hexanol,
cyclohexanol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol and poly-alcohol(cyclohexaamylose) have been determined at high
dilution as a function of the mole fraction of alcohol at 298.15 K, by a rocking twin-microcalorimeter of the heat-conduction
type.
A smoothing equation of the enthalpies of dilution against the mole fractions of alcohols are given. The graphical comparison
of experimental results with their smoothed values or literature ones, taking into account the dependence of the mole fractions,
are also presented.
It has been found for the aqueous solutions of shorter n-alcohols than hexanol that at very high dilution, exothermic values of molar enthalpies of dilution from a definite mole
fraction of alcohols to infinite dilution with the change of mole fraction is proportional to carbon number of n-alcohols. The molar enthalpies of infinite dilution of aqueous butanediol isomers and 1-hexanol were very large. Molar enthalpies
of infinite dilution of aqueous poly-alcohol (cyclohexaamylose) were endothermic.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
Dharam V.S. Jain Vijay K. Singla Suraj B. Saini Rajwant S. Sidhu 《The Journal of chemical thermodynamics》1983,15(12):1105-1107
Excess molar volumes VmE as function of mole fraction x for methylcyclohexane + benzene, + methylbenzene, + 1,4-dioxane, and + tetrahydrofuran are reported at 303.15 K. The excess molar volumes are positive and indicate the presence of weak interactions. 相似文献
3.
The preferential solvation parameters (δx1,3) of indomethacin (IMC) in 1,4-dioxane + water binary mixtures were derived from their thermodynamic properties by means of the inverse Kirkwood–Buff integrals method. δx1,3 is negative in water-rich and 1,4-dioxane-rich mixtures but positive in cosolvent compositions from 0.17 to 0.69 in mole fraction of 1,4-dioxane at 298.15 K. It is conjecturable that in water-rich mixtures, the hydrophobic hydration around the aromatic and methyl groups of the drug plays a relevant role in the solvation. The higher solvation by 1,4-dioxane in mixtures of similar cosolvent compositions could be mainly due to polarity effects. Finally, the preference of this drug for water in 1,4-dioxane-rich mixtures could be explained in terms of the higher acidic behavior of water molecules interacting with the hydrogen-acceptor groups present in IMC. 相似文献
4.
Excess molar enthalpies and heat capacities of dimethyl sulfoxide + 1,4-dioxane, dimethyl sulfoxide + 1,3-dioxolane, dimethyl sulfoxide + tetrahydropyran, dimethyl sulfoxide + tetrahydrofuran, dimethyl sulfoxide + 1,2-dimethoxyethane, and dimethyl sulfoxide + 1,2-diethoxyethane have been measured at 308.15 K and at atmospheric pressure using an LKB micro-calorimeter and a Perkin-Elmer differential scanning calorimeter. Heat capacities of pure components were determined in the range (293.15 < T/K < 423.15). The results of excess molar enthalpies were fitted to the Redlich-Kister polynomial equation to derive the adjustable parameters and standard deviations, and were used to study the nature of the molecular interactions in the mixtures. Results of excess molar enthalpy were interpreted by an extended modified cell model. 相似文献
5.
The molar execess enthalpies of C_1 to C_5 normal alcohols with 1,4-dioxane have been measured with a Picker flow microcalorimeter. From our measurements we can come to the following results. Mixing n-alcohols with 1,4-dioxane are all endothermic processes. The maximum values of H~E are situated near 0.49 mole fraction of n-alcohols. H~E of these systems increase with increasing chain length of the alcohols, whereas the increments for two neighbour-alcohols decrease with increasing the number of carbon. 相似文献
6.
Liisa Pikkarainen 《Journal of solution chemistry》1987,16(2):125-132
The molar excess enthalpies H
m
E
of binary solvent mixtures of N-methylacetamide with methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and t-butanol have been measured with a flow microcalorimeter at 40°C. The excess enthalpies are negative for methanol and positive for the other alcohols over the whole composition range, except for t-butanol which exhibits a sigmoid curve with a deep minimum at low mole fractions of the amide. The values for the primary alcohols increase in the order methanol < ethanol < 1-propanol < 1-butanol. The partial molar excess enthalpies have also been evaluated. Intermolecular interactions in these mixtures are discussed through comparison of the results with those for the corresponding binary mixtures of N,N-dimethylacetamide. 相似文献
7.
Alessandro D'Aprano Rosario De Lisi Dorina Ines Donato 《Journal of solution chemistry》1983,12(6):383-400
The densities, heat capacities, and dilution enthalpies ofn-pentanol+2-methyl-2-butanol mixtures have been measured, in many cases as a function of temperature, over the complete mole fraction range. Excesses thermodynamic properties, apparent and partial molar heat capacities, volumes and expansibilities were derived. The concentration and temperature dependences of these functions are discussed in terms of the variations of the structure of the system caused by the participation of the two alcohol molecules (with quite different steric hindrance of the alkyl chain around the-OH group) in the dynamic intermolecular association process through hydrogen bonding. 相似文献
8.
Mohammad M.H BhuiyanKazuhiro Tamura 《Thermochimica Acta》2003,405(1):137-146
Ternary excess molar enthalpies, HmE, at 298.15 K and atmospheric pressure measured by using a flow microcalorimeter are reported for the (methanol+ethanol+tetrahydropyran) and (methanol+ethanol+1,4-dioxane) mixtures. The pseudobinary excess molar enthalpies for all the systems are found to be positive over the entire range of compositions. The experimental results are correlated with a polynomial equation to estimate the coefficients and standard errors. The results have been compared with those calculated from a UNIQUAC associated solution model in terms of the self-association of alcohols as well as solvation between unlike alcohols and alcohols with tetrahydropyran or 1,4-dioxane. The association constants, solvation constants and optimally fitted binary parameters obtained solely from the pertinent binary correlation predict the ternary excess molar enthalpies with an excellent accuracy. 相似文献
9.
《The Journal of chemical thermodynamics》2007,39(3):433-437
The enthalpies of solution of 1,4-dioxane in {(1 − x)F + xH2O}, {(1 − x)NMF + xH2O}, and {(1 − x)DMF + xH2O} have been measured within the whole mole fraction range at T = 298.15 K. Based on the obtained data, the effect of substituting methyl groups at the nitrogen atom in formamide on the preferential solvation of 1,4-dioxane has been analyzed. A simple model has been proposed to describe the influence of structural and energetic properties of the mixed solvent on the energetic effect of hydrophobic hydration and preferential solvation of 1,4-dioxane by the components of the examined mixture. 相似文献
10.
Experimental molar heat capacity data (Cp
m) and excess molar heat capacity data (CpEm\mathit{Cp}^{\mathrm{E}}_{\mathrm{m}}) of binary mixtures containing water + (formamide or N,N-dimethylformamide or dimethylsulfoxide or N,N-dimethylacetamide
or 1,4-dioxane) at several compositions, in the temperature range 288.15 K to 303.15 K and atmospheric pressure, have been
determined using a modified 1455 PAAR solution calorimeter. The excess heat capacities are positive for aqueous solutions
containing 1,4-dioxane, N,N-dimethylformamide or dimethylsulfoxide, negative for solutions containing water + formamide and
show a sigmoid behavior for mixtures containing water + N,N-dimethylacetamide, over the whole composition range. The experimental
excess molar heat capacities are discussed in terms of the influence of temperature and of the organic solvent type present
in the binary aqueous mixtures, as well as in terms of the existing molecular interactions and the organic solvent’s molecular
size and structure. 相似文献
11.
The knowledge and prediction of physicochemical properties of binary liquid mixtures is of great importance for understanding
intermolecular interactions. Viscosities (η) have been investigated by using density (ρ) and kinematic viscosity (ν) measurements for 1,4-dioxane + water (D–W) mixtures over the entire range of mole fractions under atmospheric pressure,
at 311.15, 316.15 and 320.15 K, in order to increase the studied temperatures range available from the literature and to improve
the investigations. The viscosity Arrhenius activation energy of 1,4-dioxane + water mixtures was calculated from the present
experimental viscosity measurements, and those presented in a previous work at only four temperatures, and for three temperatures
in the present work, over the entire range of composition in the temperatures range from 293.15 to 323.15 K. Based on the
partial molar activation energy from the Arrhenius equation for viscosity, interactions between water and 1,4-dioxane molecules
are discussed. Comparison between some reduced Redlich–Kister functions covering the composition domain shows the existence
of two distinct behaviors. 相似文献
12.
M. V. Kulikov O. A. Antonova V. P. Slyusar V. P. Korolev 《Russian Chemical Bulletin》1995,44(9):1678-1683
Enthalpies of dissolution of acetonitrile, propylene carbonate, and 1,4-dioxane in mixtures of water with acetone or DMSO were measured in the whole concentration range of the mixed solvents. Standard enthalpies of dissolution and enthalpies of transfer of solutes from water to its mixtures with acetone or DMSO were determined. In the region of small proportions of the nonaqueous component, the enthalpy of cavity formation in the mixed solvent makes the main contribution to the variation of the enthalpy of dissolution. An increase in the proportion of the nonaqueous component leads to competition between the contributions of cavity formation and specific interaction between the solute and the solvent during solvation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1747–1752, September, 1995. 相似文献
13.
Experimental data from dielectric investigations of solutions of flourobenzene (FB) and its mesogenic derivative (1-fluoro-4-(4-pentylcyclohexyl)
benzene (FPCHB) in 1,4-dioxane are reported for various mole fractions and temperatures. The molecular dipole moments were
determined using the Guggenheim-Debye method in the temperature range of 298.2 to 318.2 K. Both fluorinated compounds show
a positive and small temperature coefficient for the effective dipole moment. Variations of the effective dipole moment and
correlation factor, g, with mole fraction in these mixtures were investigated using the Kirkwood-Frohlich equation. Dielectric measurements were
also carried out on binary mixtures of FPCHB with 1-butanol for various concentrations at 318.2 K. The Kirkwood correlation
factor, the Bruggeman factor, and the excess permittivity were determined. 相似文献
14.
Marta M. Mato M. Illobre Pedro V. Verdes José Luis Legido María Inmaculada Paz Andrade 《Fluid Phase Equilibria》2010
Excess molar enthalpies for the ternary system {x1 2-methoxy-2-methylpropane + x2 ethanol + (1 − x1 − x2) decane} and the involved binary mixture {x ethanol + (1 − x) decane} have been measured at the temperature of 298.15 K and atmospheric pressure, over the whole composition range. No experimental excess enthalpy values were found in the currently available literature for the ternary mixture under study. The results were fitted by means of different variable-degree polynomials. Smooth representations of the results are presented and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. The excess molar enthalpies for the binary and ternary system are positive over the whole range of composition. The binary mixture {x ethanol + (1 − x) decane} is asymmetric, with its maximum displace toward a high mole fraction of decane. The ternary contribution is also positive, and the representation is asymmetric. 相似文献
15.
M. M. Mato M. Illobre P. V. Verdes J. L. Legido E. Jiménez M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2007,88(2):607-611
Excess molar enthalpies
of the ternary mixture {x
1
tert-butyl methyl ether (MTBE)+x
2
ethanol+(1–x
1–x
2) octane} and the involved
binary mixture {x ethanol+(1–x) octane} have been measured at 298.15 K and atmospheric
pressure, over the whole composition range, using a Calvet microcalorimeter.
The results were fitted by means of different variable degree polynomials. 相似文献
16.
Maria D. M. C. Ribeiro da Silva Joana I. T. A. Cabral Chelsea Givens Stephanie Keown W. E. Acree Jr. 《Journal of Thermal Analysis and Calorimetry》2008,92(1):73-78
The standard (p
0=0.1 MPa) molar enthalpies of formation, in the gaseous phase, at T-298.15 K, for 2,5-dimethylpyrazine (2,5-DMePz) and for the two dimethylpyrazine-N,N′-dioxide derivatives, 2,3-dimethylpyrazine-1,4-dioxide (2,3-DMePzDO) and 2,5-dimethylpyrazine-1,4-dioxide (2,5-DMePzDO), were
derived from the measurements of standard massic energies of combustion, using a static bomb calorimeter, and from the standard
molar enthalpies of vaporization or sublimation, measured by Calvet microcalorimetry.
The mean values for the molar dissociation enthalpy of the nitrogen-oxygen bonds, 〈DH
m0〉(N-O), were derived for both N,N′-dioxide compounds. These values are discussed in terms of the molecular structure of the two N,N′-dioxide derivatives and compared with 〈DH
m0〉(N-O) values previously obtained for other N-oxide derivatives. 相似文献
17.
Shashi Singh Shahla Parveen Divya Shukla Maimoona Yasmin Manisha Gupta J. P. Shukla 《Journal of solution chemistry》2011,40(5):889-899
Experimental values of the density and ultrasonic velocity have been measured for binary mixtures of butylamine with 1-butanol
and with tert-butanol at temperatures of 293.15, 303.15 and 313.15 K over the entire mole fraction range. From these data, the excess molar
volumes, deviations in isentropic compressibility, excess internal pressures, and excess molar enthalpies have been calculated.
All of the excess functions were fitted to Redlich-Kister polynomial relations to estimate the adjustable parameters along
with the standard deviations of the fits. The variations of these excess functions with mole fraction of butylamine have been
examined. The changes in these parameters with composition suggest that the interaction between butylamine and 1-butanol is
strong, whereas its interaction with tert-butanol is weak. Further, the partial molar volumes and partial molar compressibilities at infinite dilution have also been
evaluated since these parameters provide better insight for studying intermolecular interactions. 相似文献
18.
M. A. V. Ribeiro da Silva Ana Filipa L. O. M. Santos 《Journal of Thermal Analysis and Calorimetry》2007,88(1):7-17
The standard (p
0=0.1
MPa) molar enthalpies of formation, in the condensed phase, of nine linear-alkyl
substituted thiophenes, six in position 2- and three in position 3-, at T=298.15 K, were derived from the standard massic
energies of combustion, in oxygen, to yield CO2(g)
and H2SO4·115H2O(aq),
measured by rotating-bomb combustion calorimetry. The standard molar enthalpies
of vaporization of these compounds were measured by high temperature Calvet
Microcalorimetry, so their standard molar enthalpies of formation, in the
gaseous phase, were derived.
The results are discussed in terms
of structural contributions to the energetics of the alkyl-substituted thiophenes,
and empirical correlations are suggested for the estimation of the standard
molar enthalpies of formation, at T=298.15
K, for 2- and 3-alkyl-substituted thiophenes, both in the condensed and in
the gaseous phases. 相似文献
19.
Excess molar enthalpies, HE for the binary systems formamide+methanol, + ethanol, + propan-1-ol, + butan-1-ol, + pentan-1-ol, and + hexan-1-ol have been measured at 298.15 K and atmospheric pressure with a Paar 1455 solution calorimeter. All the system present endothermic events and showed maximum positive HE values around 0.40-0.50 mole fraction of formamide. The HE values increases in the order: methanol<ethanol<propan-1-ol<butan-1-ol<pentan-1-ol<hexan-1-ol. Experimental showed insolubility of hexan-1-ol in formamide around x≅0.5 mole fraction of formamide. The excess enthalpies of the above mentioned binary systems, were used to discuss interaction between the alkan-1-ols and formamide molecules. The results are interpreted to gain insight into the changes in molecular association equilibria and structural effects in these systems through O···HO hydrogen bonding. The experimental data have been correlated using Redlich-Kister polynomials. In this research work, the thermodynamics models were also tested: NRTL, Wilson models and their parameters were calculated. The correlation of excess enthalpy data in the systems using NRTL model provides good results. 相似文献