共查询到20条相似文献,搜索用时 31 毫秒
1.
Bernazzani L. Cabani S. Conti G. Mollica V. 《Journal of Thermal Analysis and Calorimetry》2000,61(2):637-647
The excess molar enthalpies and volumes have been determined for the binary system (water+octan-1-ol or +octan-2-ol) by means
of direct calorimetric and densimetric measurements in the miscibility range. The experimental data were described through
a Redlich-Kister type equation. For excess enthalpies a sigmoidal shape is predicted,while excess volumes are negative except
for a little positive queue observed for(water+octan-1-ol) system at very low water content. Also the partial molar enthalpies
of solution and the partial molar volumes of water in the two isomeric octanols at infinite dilution have been evaluated and
discussed. A comparison is made between excess enthalpies and excess free energies calculated by the UNIFAC method.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Monika Geppert-Rybczyńska Barbara Hachuła Monika Bucek 《Journal of solution chemistry》2008,37(12):1747-1773
The densities of propan-2-ol + pentan-1-ol, + hexan-1-ol, + heptan-1-ol, + octan-1-ol + nonan-1-ol and speeds of sound in
propan-2-ol + pentan-1-ol, + heptan-1-ol, + nonan-1-ol have been measured over the whole composition range at 298.15 K. Excess
molar functions determined from the experimental data have been plotted as functions of composition. The excess molar volumes
have been interpreted on the basis of the Symmetrical Extended Real Associated Solution Model (S-ERAS). 相似文献
3.
The densities and speeds of sound in the pentan-1-ol + nonan-1-ol, pentan-1-ol + dekan-1-ol, propan-1-ol + hexan-1-ol, and
propan-2-ol + hexan-1-ol binary systems have been measured within the whole composition range at 298.15 K. The quantities
determined from the measurement data have been plotted as functions of composition. The excess molar volumes have been interpreted
on the basis of results of the Symmetrical Extended Real Associated Solution Model (S-ERAS). 相似文献
4.
Densities (ρ)of the binary systems of {difurylmethane + (ethanol or propan-1-ol or butan-1-ol or pentan-1-ol or hexan-1-ol)} have been measured with an Anton Paar DMA 4500 vibrating-tube densimeter over the entire composition range at 298.15,K and atmospheric pressure. Excess molar volumes (V
m
E
) of each binary system were determined and correlated by the Redlich-Kister equation. Limiting (V
i
E,∞) and excess partial molar volumes (V
i
E
) of components of each binary system have been calculated to provide insight into the intermolecular interactions present and the packing efficiencies. The results have been discussed in terms of specific intermolecular interactions, dispersive forces and structural effects. 相似文献
5.
《Physics and Chemistry of Liquids》2012,50(4):449-455
Excess molar enthalpies, $ H_m^E $ of N , N -dimethylacetamide + methanol, + ethanol, + propan-1-ol, + butan-1-ol, + pentan-1-ol, and + hexane-1-ol have been determined at 298.15 K and atmospheric pressure using a Parr 1455 solution calorimeter. While the excess molar enthalpies are negative for methanol and ethanol mixtures, those for propan-1-ol, butan-1-o1, pentane-1-ol, and hexan-1-ol mixtures are positive over the entire range of composition of N , N -dimethylacetamide. The $ H_m^E $ at around x , 0.5 follow the order: methanol<ethanol<propan-1-ol<butan-1-ol<pentan-1-ol<hexan-1-ol. The results are explained in terms of the self-association exhibited by the alkan-1-ols and the formation of aggregates between unlike molecules through OHO hydrogen bonding. The experimental results for mixtures are well represented by the Redlich - Kister equation. 相似文献
6.
In this paper, experimental excess molar enthalpies for the binary mixtures of R-fenchone with propan-1-ol or propan-2-ol, at four temperatures (283.15, 298.15, 313.15 and 328.15) K and atmospheric pressure are reported over the entire composition range. They have been fitted to the Redlich–Kister equation at each temperature. Excess molar enthalpies are positive in all cases, being greater for the mixture with propan-2-ol than for the mixture with propan-1-ol. These positive values of the excess enthalpy suggest the predominance of the effect due to hydrogen bond breaking over the interaction between dissimilar molecules in the mixture. Finally UNIFAC (Dortmund) method and the Quantum Continuum Method COSMO-RS have been used to predict the excess molar enthalpies. Better predictions are obtained in the case of UNIFAC model. 相似文献
7.
Ivona R. Radović Mirjana Lj. Kijevčanin Marijan Z. Gabrijel Slobodan P. Šerbanović Bojan D. Djordjević 《Chemical Papers》2008,62(3):302-312
The excess molar volumes of 51 binary mixtures containing diverse groups of organic compounds: alcohols (methanol, ethanol,
propan-1-ol, butan-1-ol, pentan-1-ol, hexan-1-ol, and heptan-1-ol), (cyclo-) alkanes (hexane, heptane, octane, nonane, decane,
undecane, dodecane, and cyclohexane), esters (diethyl carbonate and ethyl chloroacetate), aromatics (o-xylene, m-xylene, p-xylene, and ethylbenzene), ketones (acetone), and ethers (anisole), were predicted from the refractive index data, using
three types of equations coupled with several different mixing rules for refractive index calculations: the Lorentz-Lorenz,
Dale-Gladstone, Eykman, Arago-Biot, Newton, and the Oster. These systems were chosen since they belong to different classes
of organic species forming molecular interactions and intermolecular forces during mixing resulting in positive or negative,
smaller or larger deviations from ideal behaviour. The obtained results were analysed in terms of the applied equation and
mixing rule, the nature of compounds of the mixtures and the influence of alkyl chain length of the alkane or alcohol molecule.
Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May
2007. 相似文献
8.
《Physics and Chemistry of Liquids》2012,50(1):137-149
Abstract Excess molar volumes (VE ) and average thermal expansivities (α) of the systems, water (W) + n-butylamine (NBA), W + sec-butylamine (SBA), and W + tert-butylamine (TBA), have been calculated from the density data at temperatures ranging from 298.15–323.15 K. The VE and α values have been plotted as functions of mole fraction of amines. The systems show large negative excess volumes, magnitude of which varies in the order, W + TBA > W + SBA > W + NBA. The curves are found to be symmetrical along the composition axis, with minima occurring at 0.5 mole fraction of butylamines. The negative excess volumes have been interpreted primarily by two effects: (i) strong chemical interaction leading to the formation of 1:1 complexes through H-bonding and (ii) hydrophobic hydration causing significant contraction of volume. 相似文献
9.
Molar excess enthalpies H
m
E have been determined over the whole composition range for mixtures of benzene, methanol, ethanol, 1-propanol, 2-propanol
and 1-butanol with quinoline at 298.15 K using a Thermometric flow calorimeter. The results reflect a strong H-bond association
between an alkanol and quinoline which decreases with increasing length of the alkanol chain. The small H
m
E for (benzene+quinoline) reflects the similarity of the two molecules.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
S. K. Bindhani G. K. Roy Y. K. Mohanty T. R. Kubendran 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(7):1255-1264
Density, viscosity and ultrasonic velocity values for pentan-1-ol (1) + nitrobenzene (2) mixtures were measured at temperatures of 303.15 to 313.15 K. The new equations have been developed for viscosity and ultrasonic velocity by the use of statistical software Design Expert. The excess values like excess molar volume, viscosity deviation and ultrasonic velocity deviations have been calculated from density, viscosity and ultrasonic velocity respectively. The excess values were correlated using the Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. 相似文献
11.
In this paper, excess thermodynamic functions have been computed from the measured values of density, viscosity, and refractive index at T = (298.15, 303.15, and 308.15) K, ultrasonic velocity at T = 298.15 K over the entire mixture composition range of (anisole with ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, or 3-methyl butan-1-ol). Excess molar volume, VE has been calculated from densities, whereas deviations in viscosity, Δη, were computed from the measured viscosities. From ultrasonic velocities, isentropic compressibilities were calculated, from which deviations in isentropic compressibility, Δks have been computed. Lorenz-Lorentz mixture rule was used to compute molar refractivity, R from refractivity index data and from these data, deviations in molar refractivity, ΔR have been computed. Computed thermodynamic quantities have been fitted to Redlich and Kister polynomial equation to derive the coefficients and standard errors between experimental and predicted quantities. Intermolecular interactions between anisole and alkanols have been studied based on the computed excess thermodynamic quantities. 相似文献
12.
Ângela F.S. Santos Maria Luísa C.J. Moita Isabel M.S. Lampreia 《The Journal of chemical thermodynamics》2009,(12):1387-1393
Accurate density values are reported for aqueous binary mixtures of 1-propoxypropan-2-ol (1-PP-2-ol) over the whole composition range and temperatures between (283 and 303) K at intervals of 5 K. Excess molar volumes of the mixture, , apparent molar volumes of 1-PP-2-ol, Vφ,2, as well as excess partial molar volumes, , of both components were obtained over the entire composition and temperature ranges. Thermal expansibility effects on this (amphiphile + water) mixture are analysed in terms of excess molar isobaric expansions, , of the mixture and from the temperature dependence of limiting excess partial molar isobaric expansions, , for both chemical substances in the mixture. An analytical method based on Redlich−Kister fitting equations for as a function of the mole fraction has been used to obtain limiting excess partial molar volumes, . The excess properties are referred to a thermodynamically defined ideal liquid mixture. Interesting insights into the mixing process are gained from the visual impact of plots showing the composition and temperature dependence of different excess molar thermodynamic properties. The choice of 1-PP-2-ol was specially meant to highlight the role of branching in the alcohol versus alkoxy moieties. The present thermodynamic data are compared with that for isomeric 2-butoxyethanols, which are structural isomers of 1-PP-2-ol, and for 2-isopropoxyethanol. From this comparison an extended insight is gained into the role of branching and chain length on the mixing process and particularly in changes of local H-bond patterns of hydration water. 相似文献
13.
Excess molar volumes Vm^E and kinematic viscosities v have been measured as a function of composition for binary mixtures of propylene glycol monomethyl ether (1-methoxy-2-propanol), MeOCH2CH(OH)Me, propylene glycol monoethyl ether (1-ethoxy-2-propanol), EtOCH2CH(OH)Me, propylene glycol monopropyl ether (1-propoxy-2-propanol), PrOCH2CH(OH)Me, propylene glycol monobutyl ether (1-butoxy-2-propanol), BuOCH2CH(OH)Me, and propylene glycol tert-butyl ether (1-tert-butoxy-2-propanol), t-BuOCH2CH(OH)Me with 1-butanol, and 2-butanol, at 298.15 K and atmospheric pressure. The excess molar volumes are negative across the entire range of composition for all the systems with 1-butanol, and positive for the systems 2-butanol+ 1-methoxy-2-propanol, and +1-propoxy-2-propanol, negative for the systems 2-butanol+1-butoxy-2-propanol, and change sign for the systems 2-butanol+ 1-ethoxy-2-propanol, and + 1-tert-butoxy-2-propanol. From the experimental data, the deviation in dynamic viscosity η from ∑χiηi has been calculated. Both excess molar volumes and viscosity deviations have been correlated using a Redlich-Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors. 相似文献
14.
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
15.
P. V. Verdes M. M. Mato J. L. Legido M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2008,92(1):179-183
Densities at 298.15 K and atmospheric pressure have been measured, using a DMA 4500 Anton Paar densimeter, for the ternary
mixture methyl tert-butyl ether (MTBE)+1-pentanol+nonane and for the involved binary mixture 1-pentanol+nonane. In addition, excess molar volumes
were determined from the densities of the pure liquids and mixtures. Suitable fitting equations have been used in order to
correlate adequately the excess molar volumes.
Experimental data were also used to test several empirical expressions for estimating ternary properties from experimental
binary results. 相似文献
16.
Sonia Freire H. Casas Esther Rilo Luisa Segade O. Cabeza E. Jiménez 《Journal of Thermal Analysis and Calorimetry》2005,80(2):285-288
Summary In this paper we present excess molar volumes and excess molar enthalpies of binary and ternary mixtures containing propyl propanoate, hexane and cyclohexane as components at 298.15 K. Excess molar volumes were calculated from the density of the pure liquids and mixtures. The density was measured using an Anton Paar DMA 60/602 vibrating-tube densimeter. Excess molar enthalpies were obtained using a Calvet microcalorimeter 相似文献
17.
The densities of the (cyclohexane + pentane, or hexane, or heptane, or octane, or nonane) systems were measured at the temperature
298.15 K by means of a vibrating-tube densimeter. Their respective excess molar volumes were calculated and correlated using
the fourth-order Redlich—Kister equation, with the maximum likelihood principle being applied in the determination of the
adjustable parameters. The values of excess molar volumes were negative for the cyclohexane + pentane system, whereas they
were positive for the other systems with the values increasing with the number of carbon atoms in the respective alkane molecules. 相似文献
18.
Experimental densities were measured for the system 1-methyl-3-octyl-imidazolium tetrafluoroborate [OMIM][BF4] + butan-1-ol, + pentan-1-ol at 298.15 K and ambient pressure using a vibrating tube densimeter, taking into account the
influence of the viscosity correction. Excess molar volumes VE have been determined. VE is quite small and negative in the alcohol-rich range of the mixture composition and positive in the alcohol-poor range.
LLE data of [OMIM][BF4] + pentan-1-ol have been measured using a laser light scattering cell for detecting cloud points at different compositions
in the temperature range of 282–292 K. A miscibility gap with an upper critical solution temperature (UCST) of 292 K has been
found. 相似文献
19.
As a continuation of our studies of the excess functions of binary systems containing acetonitrile (1−x)–amines (x) mixtures, the molar heat capacity, Cp, and excess molar heat capacity, Cp
E, of acetonitrile + diethylamine or sec-butylamine mixtures have been determined as a function of composition at 288.15, 293.15,
298.15 and 303.15 K at atmospheric pressure using a modified 1455 PARR solution calorimeter. The excess heat capacity data
are positive for both systems over the whole composition range. The experimental data on the excess molar heat capacity are
discussed in terms of the influence of the magnitude of the experimental excess molar enthalpy, H
E, over the curve shaped for the experimental Cp
E data, molecular interactions in the mixtures, isomeric effect of the amines and modeling of Cp
E data. 相似文献
20.
The viscosity deviation (Δη), the excess molar volume (V
E) and the ultrasonic speed (u) have been investigated from viscosity (η) and density (ρ ) measurements of binary liquid mixtures of 1,2-dimethyoxyethane with methanol, ethanol, propan-1-ol, butan-1-ol,
pentan-1-ol, hexan-1-ol or octan-1-ol over the entire range of composition at 298.15 K. The excess volumes are negative over
the entire range of composition for all of the mixtures with the exception of hexan-1-ol and octan-1-ol. The excess isentropic
compressibilities (K
S
E) and viscosity deviations are negative for all of the mixtures. The magnitudes of the negative values of V
E decrease with the number of carbon atoms of the alkan-1-ol. The trend of increasing K
S
E values with the chain length of the alkanol is similar to that observed in the case of V
E. Graphs of V
E, Δ η, K
S
E, Δ u, L
f
E and Z
E against composition are presented as a basis for a qualitative discussion of the results. 相似文献