Excess functions of (an alkane + carbon disulphide) at 298.15 K

Vapour pressures, excess enthalpies, and densities for {(1?x)C₆H₁₄ + xCS₂} {(1?x)C₁₀H₂₂ + xCS₂}, {(1?x)C₁₃H₂₈ + xCS₂}, and {(1?x)C₁₆H₃₄ + xCS₂} have been measured at 298.15 K. It was found that H_m^E and V_m^E increase as chain length increases while G_m^E diminishes, becoming negative for hexadecane.     

Excess molar volumes of (cyclohexanone+trichloromethane,or 1,2-dichloroethane,or trichloroethene,or 1,1,1-trichloroethane,or cyclohexane) at T=308.15 K,and of (cyclohexanone+dichloromethane) at T=303.15 K

Excess molar volumes V_m^E have been measured using a dilatometric technique for mixtures of cyclohexanone (C₆H₁₀O) with trichloromethane (CHCl₃), 1,2-dichloroethane (CH₂ClCH₂Cl), trichloroethene (CHClCCl₂), 1,1,1-trichloroethane (CCl₃CH₃), and cyclohexane (c-C₆H₁₂) at T=308.15 K, and for cyclohexanone+dichloromethane (CH₂Cl₂) at T=303.15 K. Throughout the entire range of the mole fraction χ of C₆H₁₀O, V_m^E has been found to be positive for χ C₆H₁₀O+(1−χ)c-C₆H₁₂, and negative for χ C₆H₁₀O+(1−χ)CH₂Cl₂, χ C₆H₁₀O+(1−χ)CHClCCl₂, χ C₆H₁₀O+(1−χ)CHCl₃, and χ C₆H₁₀O+(1−χ) CCl₃CH₃. For χ C₆H₁₀O+(1−χ)CH₂ClCH₂Cl, V_m^E has been found to be positive at lower values of χ and negative at high values of χ, with inversion of sign from positive to negative values of V_m^E for this system occurring at χ∼0.78. Values of V_m^E for the various systems have been fitted by the method of least squares with smoothing equation, and have been discussed from the viewpoint of the existence specific interactions between the components.     

Excess molar enthalpies of (methanol + 1-propanol) + oxane or 1,4-dioxane mixtures at the temperature 298.15 K

Experimental excess molar enthalpies H_m^E at the temperature 298.15 K and atmospheric pressure in a flow microcalorimeter are reported for the ternary mixtures: {x₁CH₃OH+x₂C₂H₅OH+(1−x₁−x₂)C₅H₁₀O} and {x₁CH₃OH+x₂C₂H₅OH+(1−x₁−x₂)C₄H₈O₂}. The results have been correlated by means of a polynomial equation and used to construct constant excess enthalpy contours. Further, the results have been compared with those calculated from a UNIQUAC associated-solution model taking into consideration the molecular association of like alcohols, solvation between unlike alcohols and alcohols with oxane (tetrahydropyran) or 1,4-dioxane using only binary information.     

Excess molar quantities of (a halogenated n-alkane + an n-alkane) A comparative study of mixtures containing either 1-chlorobutane or 1,4-dichlorobutane

Excess molar volumes V_m^E at 298.15 K were obtained, as a function of mole fraction x, for series I: {x1-C₄H₉Cl + (1 ? x)n-C_lH_{2l + 2}}, and II: {x1,4-C₄H₈Cl₂ + (1 ? x)n-C_lH_{2l + 2}}, for l = 7, 10, and 14. 10, and 14. The instrument used was a vibrating-tube densimeter. For the same mixtures at the same temperature, a Picker flow calorimeter was used to measure excess molar heat capacities C_{p, m}^E at constant pressure. V_m^E is positive for all mixtures in series I: at x = 0.5, V_m^E/(cm³ · mol^?1) is 0.277 for l = 7, 0.388 for l = 10, and 0.411 for l = 14. For series II, V_m^E of {x1,4-C₄H₈Cl₂ + (1 ? x)n-C₇H₁₆} is small and S-shaped, the maximum being situated at x_max = 0.178 with V_m^E(x_max)/(cm³ · mvl^?1) = 0.095, and the minimum is at x_min = 0.772 with V_m^E(x_min)/(cm³ · mol^?1) = ?0.087. The excess volumes of the other mixtures are all positive and fairly large: at x = 0.5, V_m^E/(cm³ · mol^?1) is 0.458 for l = 10, and 0.771 for l = 14. The C_{p, m}^Es of series I are all negative and |C_{p, m}^E| increases with increasing l: at x = 0.5, C_{p, m}^E/(J · K^?1 · mol^?1) is ?0.56 for l = 7, ?1.39 for l = 10, and ?3.12 for l = 14. Two minima are observed for C_{p, m}^E of {x1,4-C₄H₈Cl₂ + (1 ? x)n-C₇H₁₆}. The more prominent minimum is situated at x′_min = 0.184 with C_{p, m}^E(x′_min)/(J · K^?1 · mol^?1) = ?0.62, and the less prominent at x″_min = 0.703 with C_{p, m}^E(x″_min)/(J · K^?1 · mol^?1) = ?0.29. Each of the remaining two mixtures (l = 10 and 14) has a pronounced minimum at low mole fraction (x_min = 0.222 and 0.312, respectively) and a broad shoulder around x = 0.7.     

Excess enthalpies of some aromatic aldehydes in n-hexane, n-heptane and benzene

Calorimetric measurements of molar excess enthalpies, H^E, at 298.15 K, of mixtures containing aromatic aldehydes of general formula C₆H₅(CH₂)_mCHO (with m = 0, 1 and 2) + n-hexane, n-heptane or benzene are reported, together with the values of H^E at equimolar composition compared with the corresponding values of H^E for the aromatic ketones in the same solvents. The experimental results clearly indicate that the intermolecular interactions between the carbonyl groups (CHO) are influenced by the intramolecular interactions between the carbonyl and phenyl groups, particularly for the mixtures containing benzaldehyde.     

Vapor–liquid equilibria and excess properties of octane + 1,1-dimethylpropyl methyl ether (TAME) mixtures

Vapor–liquid equilibrium (VLE) data are reported for the binary mixtures formed by octane and the branched ether 1,1-dimethylpropyl methyl ether (tert-amyl methyl ether or TAME). A Gibbs–van Ness type apparatus was used to obtain total vapor pressure measurements as a function of composition at 298.15, 308.15, 318.15 and 328.15 K. The system shows positive deviations from Raoult’s law. These VLE data are analyzed together with data previously reported for octane+TAME mixtures: VLE data at 323.15 and 423.15 K, excess enthalpy (H_m^E) data at 298.15 and 313.15 K and excess volume (V_m^E) data at 298.15 K. The UNIQUAC model, the lattice–fluid (LF) model, and the Flory theory are used to simultaneously correlate VLE and H_m^E data. The two latter models are then used to predict V_m^E data. The original UNIFAC group contribution model and the modified UNIFAC (Dortmund model) are used to predict VLE data.     

Excess molar volumes of (ethyl formate or ethyl acetate + an isomer of hexanol) at 298.15 K

Excess molar volumes V_m^E were determined over the entire composition range at 298.15 K for ethyl formate or ethyl acetate + hexan-1-ol, +2-methylpentan-1-ol, +3-methylpentan-2-ol, +2-methylpentan-3-ol, +3-methylpentan-3-ol, +2-methylpentan-2-ol, +4-methyl-pentan-2-ol, and +hexan-2-ol. Excess volumes were determined from density measurements made with a vibrating-tube densimeter. The V_m^E values were all positive, decreasing with the n value of the ester: C_n?1H_2n?1CO₂C₂H₅.     

Excess molar volumes and viscosities of mixtures of some n-alkoxyethanols with dialkyl carbonates at 298.15 K

Excess molar volumes V_m^E and viscosities η have been measured as a function of composition at atmospheric pressure and 298.15 K for nine {an alkoxyethanol+dimethyl carbonate (C₃H₆O₃), diethyl carbonate (C₅H₁₀O₃), or propylene carbonate (C₄H₆O₃)} mixtures. The alkoxyethanols were 2-methoxyethanol (CH₃OCH₂CH₂OH), 2-(2-methoxyethoxy)ethanol {CH₃(OCH₂CH₂)₂OH}, and 2-{2-(2-methoxyethoxy)ethoxy}ethanol {CH₃(OCH₂CH₂)₃OH}. The V_m^E for each of the carbonate mixtures studied decrease in magnitude as the polar head group of the alkoxyethanol increases. From the experimental results, deviation in the viscosity (Δlnη) have been calculated. The experimental results have been correlated using the Redlich–Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behaviour of the components.     

Excess heat capacities and excess volumes of binary liquid mixtures of chloroform with cyclic ethers at 298.15 K

Molar excess heat capacities at constant pressure, C^E_p, of binary liquid mixtures chloroform + oxolane, chloroform + 1,3-dioxolane, chloroform + oxane, and chloroform + 1,4-dioxane have been determined at 298.15 K from measurements of volumetric heat capacities in a Picker flow microcalorimeter. A precision of ±0.04 J K^?1 mole^? was achieved by using the stepwise procedure. Experimental molar excess heat capacities are compared with values derived from H^E results at different temperatures. Excess molar volumes, V^E, for the same systems at 298.15 K have been determined by measuring the density of the pure liquids and solutions with a high-precision digital flow densimeter.     

Temperature dependence of the volumetric properties of some alkoxypropanols + n-alkanol mixtures

The excess molar volumes V_m^E for binary liquid mixtures containing dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether and methanol, 1-propanol, 1-pentanol and 1-heptanol have been measured as a function of composition using a continuous dilution dilatometer at T=(288.15, 298.15, and 308.15) K and atmospheric pressure over the whole concentration range. The excess volume results allowed the following mixing quantities to be reported in all range of concentrations or at equimolar concentrations: α, volume expansivity; (∂V_m^E/∂T)_p; (∂H^E/∂P)_T at T=298.15 K. The obtained results have been compared at T=298.15 K with the calculated values by using the Flory theory of liquid mixtures. The theory predicts the α, and α^E values rather well, while the calculated values of (∂V_m^E/∂T)_p and (∂H^E/∂P)_T show general variation with the alkyl chain length of the alkoxypropanols. The results are discussed in terms of order or disorder creation.     

Measurements of HmE and VmE for (n-butane + sulphur hexafluoride) in the supercritical region at the pressure 6.00 MPa

A flow mixing calorimeter followed by a vibrating-tube densimeter has been used to measure excess molar enthalpies H_m^E and excess molar volumes V_m^E of {xC₄H₁₀+(1−x)SF₆}. Measurements over a range of mole fractions x have been made in the supercritical region at the pressure p=6.00 MPa and at seven temperatures in the range T=311.25 K to T=425.55 K. The H_m^E(x) measurements at T=351.35 K were found to exhibit an unusual double maximum. Measurements at all temperatures are compared with the Patel–Teja equation of state with the parameters determined by solving a cubic equation as recommended, and also with parameters determined by the method suggested by Valderamma and Cisternas who proposed equations which are a function of the critical compression factor. The overall fit to the H_m^E and V_m^E measurements obtained using Valderamma and Cisternas equations was found to be better than that obtained using the parameters according to the method suggested by Patel and Teja.     

Excess molar enthalpies of the ternary system <Emphasis Type="Italic">p</Emphasis>-xylene+decane+diethyl carbonate

Excess molar enthalpies of the ternary system {x ₁ p-xylene+x ₂decane+(1–x ₁–x ₂)diethyl carbonate} and the involved binary mixtures {p-xylene+(1–x)decane}, {xp-xylene+(1–x)diethyl carbonate} and {xdecane+(1–x)diethyl carbonate} have been determined at the temperature of 298.15 K and atmospheric pressure, over the whole composition range, using a Calvet microcalorimeter. The experimental excess molar enthalpies H _m ^E are positive for all the binary systems studied over the whole composition range. Excess molar enthalpy for the ternary system is positive as well, showing maximum values at x ₁=0, x ₂=0.4920, x ₃=0.5080, H _m,123 ^E=1524 J mol^–1.     

Excess molar heat capacities and excess molar volumes of some mixtures of propylene carbonate with aromatic hydrocarbons

Excess molar volumes V ^E and excess molar heat capacities C _P ^E at constant pressure have been measured, at 25°C, as a function of composition for the four binary liquid mixtures propylene carbonate (4-methyl-1,3-dioxolan-2-one, C₄H₆O₃; PC) + benzene (C₆H₆;B), + toluene (C₆H₅CH₃;T), + ethylbenzene (C₆H₅C₂H₅;EB), and + p-xylene (p-C₆H₄(CH₃)₂;p-X) using a vibrating-tube densimeter and a Picker flow microcalorimeter, respectively. All the excess volumes are negative and noticeably skewed towards the hydrocarbon side: V ^E (cm³-mol^–1) at the minimum ranges from about –0.31 at x₁=0.43 for {x₁C₄H₆O₃+x₂p-C₆H₄(CH₃)₂}, to –0.45 at x₁=0.40 for {x₁C₄H₆O₃+x₂C₆H₅CH₃}. For the systems (PC+T), (PC+EB) and (PC+p-X) the C _P ^E s are all positive and even more skewed. For instance, for (PC+T) the maximum is at x _1,max =0.31 with C _P,max ^E =1.91 J-K^–1-mol^–1. Most interestingly, C _P ^E of {x₁C₄H₆O₃+x₂C₆H₆} exhibits two maxima near the ends of the composition range and a minimum at x _1,min =0.71 with C _P,min ^E =–0.23 J-K^–1-mol^–1. For this type of mixture, it is the first reported case of an M-shaped composition dependence of the excess molar heat capacity at constant pressure.Communicated at the Festsymposium celebrating Dr. Henry V. Kehiaian's 60^th birthday, Clermont-Ferrand, France, 17–18 May 1990.     

Determination of excess molar enthalpies for the ternary system <Emphasis Type="Italic">p</Emphasis>-xylene+octane+diethyl carbonate

Excess molar enthalpies, H ^E, for the binary mixtures {p-xylene+(1–x) octane}, {x p-xylene+(1–x) diethyl carbonate}, {x octane+(1–x) diethyl carbonate} and the corresponding ternary system {x ₁ p-xylene+x ₂ octane+(1–x ₁–x ₂) diethyl carbonate} have been measured by using a Calvet microcalorimeter at 298.15 K under atmospheric pressure. The experimental H ^E values are all positive for the binary and ternary mixtures over the entire composition range.     

Liquid density,viscosity and spectroscopic studies of binary mixture of tetraethylene glycol + 1,2-ethanediamine for CO2 capture

Thermophysical properties for binary mixture of tetraethylene glycol (T₄EG) (1) + 1,2-ethanediamine (EDA) (2), a potential scrubbing solution for the absorption of CO₂, are very important as well as lacking in the literatures. This work reports densities and viscosities over the entire concentration range for the binary mixture at T = (293.15-318.15) K under atmospheric pressure. According to the experimental density and viscosity values, the mixtures’ excess molar volume (V_m^E), absolute viscosity deviation (?η), excess free energies of activation (?G*^E), apparent molar volumes, partial molar volumes and isobaric thermal expansion coefficient were calculated, respectively. Meanwhile, the V_m^E, ?η and ?G*^E values were fitted by a Redlich–Kister equation to obtain coefficients. To further study, the Fourier transform infrared, UV-Vis and fluorescence spectra of T₄EG + EDA mixtures with various concentrations were measured, and the intermolecular interaction of T₄EG with EDA was also discussed as the formation of –OCH₂CH₂O–H···N(H₂)CH₂CH₂(H₂)N···.     

Excess enthalpies of (methyl propanoate or methyl pentanoate + 1-alkanol) at 298.15 K

The excess molar enthalpies H_m^E of methyl propanoate or methyl pentanoate + 1-butanol, + 1-hexanol, + 1-octanol, and + 1-decanol have been determined experimentally at 298.15 K using a Calvet microcalorimeter. For all these mixtures H_m^E > 0; the values increase with the chain length of the alkanol but decrease as the ester chain lengthens.     

Enthalpies of Solution of Aliphatic Amines, Aliphatic Benzene, and Alkane in Dimethyl Sulfoxide at 298.15 K

The enthalpies of solution of aliphatic compounds [{aliphatic amine, H(CH₂) _n NH₂, n = 3 to 10}, aliphatic benzene {H(CH₂) _n C₆H₅, n = 0 to 8}, and alkane {H(CH₂) _n H, n = 6 to 10}] in dimethyl sulfoxide have been measured at 298.15 K in the low concentration range from x = 5 × 10^?6 to x = 0.002. The partial molar enthalpies at infinite dilution of each aliphatic compound were determined and were found to increase linearly with increasing number of methylene groups. The enthalpic group contribution of methylene, phenyl, methyl, hydroxyl, nitrile, and amine in aliphatic compounds were 1.55, 2.65, 3.81, ?2.55, ?3.71, and ?4.43 kJ-mol^?1, respectively.     

Densities and excess volumes of the ternary system butyl ethanoate + n-decane + 1-chlorobutane at 298.15 K

Excess molar volumes at 298.15 K and atmospheric pressure were measured for {x₁ CH₃CO₂(CH₂)₃CH₃ + x₂ C₁₀H₂₂ + (1 − x₁ − x₂) Cl(CH₂)₃CH₃} and the corresponding binary mixtures, with an Anton Paar densimeter. All the experimental values were compared with the results obtained by different prediction methods.     

Excess heat capacities and excess volumes of binary liquid mixtures of 1,1,1,-trichloroethane with cyclic ethers at 298.15 K

Measurements of volumetric heat capacities at constant pressure, C_p/V (V being the molar volume), at 298.15 K, of the binary liquid mixtures 1,1,1-trichloroethane + oxolane, +1,3-dioxolane, +oxane, +1,3-dioxane, and +1,4-dioxane were carried out in a Picker-type flow microcalorimeter. Molar heat capacities at constant pressure. C_p, and molar excess heat capacities, C^E_p, were calculated from these results as a function of the mole fraction. C^E_p values for these systems are positive and the magnitude depends on the size of the cycle and on the relative position of the oxygen atoms in the cyclic diethers. The precision and accuracy for C^E_p are estimated as better than 2%. Molar excess volumes, V^E, for the same systems, at 298.15 K, have been determined from density measurements with a high-precision digital flow densimeter. The experimental results of V^E and C^E_p, are interpreted in terms of molecular interactions.     

Excess thermodynamic parameters of binary mixtures of methanol,ethanol, 1-propanol,and 2-butanol + chloroform at (288.15–323.15 K) and comparison with the Flory theory

In this work we used the experimental result for calculating the thermal expansion coefficients α, and their excess values α ^E , and isothermal coefficient of pressure excess molar enthalpy and comparison the obtain results with Flory theory of liquid mixtures for the binary mixtures {methanol, ethanol, 1-propanol and 2-butanol-chloroform} at 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15 K. The excess thermal expansion coefficients α ^E and the isothermal coefficient of pressure excess molar enthalpy ((∂H _m^E/∂P) _T,x for binary mixtures of {methanol and ethanol + chloroform} are S-shaped and for binary mixtures of {1-propanol and 2-butanol + chloroform} are positive over the mole fraction. The isothermal coefficient of pressure excess molar enthalpy (∂H _m^E/∂P) _T,x , are negative over the mole fraction range for binary mixture of {1-propanol and 2-butanol + chloroform}. The calculated values by using the Flory theory of liquid mixtures show a good agreement between the theory and experimental.