Dilution Dilatometer Research Articles

Volumetric properties of (alkoxypropanol + n-alkanol) systems at 298.15 K

Excess molar volumes V m E for binary liquid mixtures of ( n-alkanol + 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-propoxy-2-propanol, 1-butoxy-2-propanol, or 1- tert-butoxy-2-propanol) have been measured as a function of composition using a continuous dilution dilatometer at 298.15 K and atmospheric pressure over the full range of composition. The n-alkanols were methanol, ethanol, and 1-propanol. The V m E for each of the mixture studied are negative over the whole mole fraction range. For each case, the V m E increases in a positive direction with increase in chain length of the n-alkanol. The V m E results have been used to estimate the excess partial molar volumes V¯ m,i E of the components.

Excess Volumetric and Spectroscopic Properties of Mixtures of Some n-Alkoxyethanols and of Some Polyethers with 2-Pyrrolidinone and N-Methyl-2-Pyrrolidinone at 298.15 K

Excess molar volumes VmE for binary liquid mixtures of n-alkoxyethanols or polyethers + 2-pyrrolidinone or N-methyl-2-pyrrolidinone have been measured with a continuous dilution dilatometer at 298.15 K and atmospheric pressure as a function of composition. The alkoxyethanols are diethylene glycol monomethylether, 2-(2-methoxyethoxy) ethanol, CH3(OC2H4)2OH; diethylene glycol monoethylether, 2-(2-ethoxyethoxy) ethanol, C2H5(OC2H4)2OH; and diethylene glycol monobutylether, 2-(2-butoxyethoxy) ethanol, C4H9(OC2H4)2OH; whereas the polyethers are diethylene glycol dimethylether, bis(2-methoxyethyl)ether, CH3(OC2H4)2OCH3; diethylene glycol diethylether, bis(2-ethoxyethyl)ether, C2H5(OC2H4)2OC2H5; and diethylene glycol dibutylether, bis(2-butoxyethyl)ether, C4H9(OC2H4)2OC4H9. In all mixtures the excess molar volumes are negative and symmetric across the entire composition range. The excess volumes are fitted to the Redlich–Kister polynomial equation to obtain the binary coefficients and the standard errors. The experimental results have also been discussed on the basis of IR measurements.

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.

Volumetric properties of binary mixtures of 2-alkoxyethanols with N,N-dimethylformamide and N,N-dimethylacetamide at 298.15 K

The excess molar volumes (V m E) for binary liquid mixtures of (2-alkoxyethanol +N,N-dimethylformamide or N,N-dimethylacetamide) have been measured with a continuous dilution dilatometer at 298.15 K and atmospheric pressure over the entire composition range. The 2-alkoxyethanols were 2-methoxyethanol (CH 3OCH 2CH 2OH), 2-ethoxyethanol (C 2H 5OCH 2CH 2OH), and 2-butoxyethanol (C 4H 9OCH 2CH 2OH). The excess molar volumes are negative and symmetric over the entire range of composition for all mixtures. The results have been used to estimate the partial molar volumes V mi of the components. The change of V m E and V m i with composition and the number of alkyl chain-length in the alkoxyethanol molecule are discussed with reference to the nature of interactions between the component molecules.

Temperature Dependence of the Volumetric Properties of Binary Mixtures Containing Polyethers and 1-Propanol

Excess molar volumes (VEm) were measured at 288.15, 298.15, and 308.15 K and atmospheric pressure as a function of composition with a continuous dilution dilatometer for the binary mixtures of 1-propanol [CH3CH2CH2OH] with glymes [CH3O(CH2CH2O)mCH3, m=1,2,3, and 4]. With these results and other thermodynamic data from the literature, the following mixing quantities have been reported over the complete range of concentration or at equimolar concentration: α, volume expansivity; αE, excess volume expansivity; (∂VEm/∂T)P, and (∂HE/∂P)T at 298.15 K. The Prigogine–Flory–Patterson theory (PFP) of liquid mixtures has been applied to estimate interaction, free-volume, and internal-pressure contributions to VEm and to estimate the different mixing quantities for the mixtures. The calculated values using the PFP theory were then compared at 298.15 K with the experimentally obtained results. The PFP theory predicts excess volume VEm values rather well, while the calculated value of (∂VEm/∂T)P and (∂HE/∂P)T by using the Flory theory show general variation with the chain length of the glyme. The (∂VEm/∂T)P and (∂HE/∂P)T show deviations between theoretical and experimental values that are slightly larger in systems with lower glyme.

Physicochemical properties in mixtures of hexamethylphosphortriamide with 2,2,2-trichloroethanol or 2,2,2-trifluoroethanol or 1,1,1,3,3,3-hexafluoropropan-2-ol

The excess volume V E, ultrasonic speed u and 1 H NMR measurements have been carried out in mixtures of hexamethylphosphortriamide (HMPA) and 2,2,2-trichloroethanol (TCE) or 2,2,2-trifluoroethanol (TFE) or 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) over the whole composition range. The excess volume and ultrasonic velocity have been measured with the help of continuous dilution dilatometer and ultrasonic time intervalometer based on a ‘pulse-echo-overlap’ (PET) technique, respectively at 303.15 K. V E is positive throughout the whole composition range in the mixture of HMPA and TFE whereas it shows an S-shaped behaviour, negative at low x and positive at high x in the other two mixtures HMPA+TCE and HMPA+HFP. The V E results have been utilised to calculate the partial molar volumes of the components. Estimates of the isentropic molar quantity K S and of its excess counterpart K S E were obtained from excess volume data in combination with ultrasonic speed values. The K S E is positive for HMPA+TFE but negative for HMPA+HFP mixture. It is both negative and positive for HMPA+TCE with very small positive values at very high mole fraction of HMPA. The order is TFE>TCE>HFP. The apparent parameters have also been estimated for support in explaining the results of volume and compressibilities. An attempt has also been made to correlate these with the values of the spectral parameter Δ δ (HMPA-halogenated alkanol) calculated from the 1 H NMR data.

Vapor–liquid equilibria and excess molar volumes of diethylamine(1) + acetone(2) and diethylamine(1) + acetonitrile(2) binary systems

Isothermal vapor–liquid equilibrium (VLE) data for diethylamine(1)+acetone(2) and diethylamine(1)+acetonitrile(2) binary systems were obtained at 323.15 K by dynamic method. Excess molar volumes at 298.15 K for these systems were measured by a dilution dilatometer. VLE data have been checked for thermodynamic consistency and correlated by Wilson, NRTL and UNIQUAC equations. UNIFAC group interaction parameters for CH 2NHCH 3CO and CH 2NHCH 3CN pairs are also obtained from the experimental VLE data.

Excess Molar Volumes and Partial Molar Volumes of Dipropylene Glycol Monomethyl Ether + n-Alkanol Mixtures at 25°C

The excess molar volumes VE for binary liquid mixtures containing dipropylene glycol monomethyl ether and methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol have been measured using a continuous dilution dilatometer over the whole mole fraction range at 25°C at atmospheric pressure. VE are negative over the whole composition range except for the systems containing 1-pentanol, 1-hexanol, or 1-heptanol which are positve at every composition. VE increases in a positive direction with increase in chain length of the n-alcohol. The results have been used to estimate the excess partial molar volumes ViE of the components. The change of VE and ViE with composition and the number of carbon atoms in the alcohol molecule are discussed as a basis to understand some of the molecular interactions present in the mixtures:

Excess volumes in ( N-methylacetamide + ethanol + water) at T = 313.15 K

Excess volumes V E measured at the temperature 313.15 K in a dilution dilatometer are reported for ( N -methylacetamide + ethanol), and for ( N -methylacetamide + ethanol + water). The results have been analysed using various correlation equations and the possibility of predicting the ternary V E values from the binary ones is examined. The results for ( N -methylacetamide + ethanol) are compared with previously obtained data for ( N -methylacetamide, or N -methylformamide, or N, N -dimethylformamide + water, or methanol, or ethanol).

Excess volumes in (N-methylacetamide + methanol + water) at the temperature 313.15 K

Excess molar volumes, VE, measured at the temperature 313.15 K in a dilution dilatometer are reported for binary mixtures (N -methylacetamide + water), (N -methylacetamide + methanol), and for the ternary mixture (N -methylacetamide + methanol + water). The results have been analysed using various correlation equations and the possibility of predicting the ternary VEvalues from the binary ones is examined.

Excess Molar Volumes and Viscosities of Mixtures Containing Some Polyethers + Acetonitrile at 298.15 K

Excess molar volumes and viscosities η for ethylene glycol dimethyl ether (monoglyme), CH3OC2H4OCH3, diethylene glycol dimethyl ether (diglyme), CH3(OC2H4)2OCH3, triethylene glycol dimethyl ether (triglyme), CH3(OC2H4)3OCH3, tetraethylene glycol dimethyl ether (tetraglyme), and CH3(OC2H4)4OCH3 + acetonitrile (CH3CN) have been measured as a function of composition at 298.15 K and atmospheric pressure. The measurements of excess volume have been carried out with a continuous dilution dilatometer. The excess volumes are all negative over the entire range of composition and decrease with increasing number of oxygen atoms in the glyme molecule. The results are discussed in terms of dipole−dipole interactions between glymes and acetonitrile and their magnitudes increasing with the dipole character of the glyme molecules.

Volumetric properties of binary systems between tetralin and alkylbenzenes

Excess molar volumes of binary mixtures of 1,2,3,4-tetrahydronaphthalene (tetralin) with benzene, toluene, ethylbenzene, n-propylbenzene, iso-propylbenzene, n-butylbenzene, tert-butylbenzene, and sec-butylbenzene over the whole mole fraction range were measured with a continuous dilution dilatometer. All the experimental values, except that of benzene system, are negative. Flory theory and its extended form, the two-parameter method, were used to describe the volumetric properties. Theoretical prediction of volumetric properties is discussed in terms of the efficiency of the segmental contact sites. It is concluded that the two-parameter method can improve greatly the theoretical results.

Volumetric properties of ( n-alkanol+polyether) systems at 298.15 K

Excess molar volumes V E for binary liquid mixtures of ( n-alkanol+2,5-dioxahexane, 2,5,8-trioxanonane, 2,5,8,11-tetraoxadodecane, 3,6,9-trioxaundecane, or 5,8,11-trioxapentadecane) have been measured as a function of compositions using a continuous dilution dilatometer at 298.15 K and atmospheric pressure over the full range of compositions. The n-alkanols were methanol, ethanol, 1-butanol, and 1-pentanol. The results have been used to estimate the excess partial molar volumes of the components. The V E for each of the mixture studied are negative with the exception of 1-pentanol+2,5,8-trioxanonane or 2,5,8,11-tetraoxadodecane and change sign for 1-butanol+2,5-dioxahexane over the whole composition range. For each case, the V E increases as the chain length of the n-alkanol increases.

Excess Molar Volumes and Excess Gibbs Energies in N-Methylformamide + Water, or + Methanol, or + Ethanol at the Temperature 303.15 K

Excess volumes VE measured in a dilution dilatometer and total vapor pressures at the temperature 303.15 K are reported for (N-methylformamide + water), (N-methylformamide + methanol), and (N-methylformamide + ethanol) over the entire composition range. The total vapor pressure measurements were made by a modified static method. The excess molar volumes are negative for all the mixtures over the entire composition range; the vapor pressure measurements show only small negative deviations from ideality for these systems.

Excess Molar Volumes of Binary Liquid Mixtures of 1-Propanol and of 2-Propanol + Propane-1,2-diol, 1-Methoxy-2-propanol, 1-Ethoxy-2-propanol, and 1-tert-Butoxy-2-propanol and Water + 1-Methoxy-2-propanol and 1-Ethoxy-2-propanol at 298.15 K

Excess molar volumes measured as a function of composition at 298.15 K using a dilution dilatometer, are reported for the 10 binary mixtures of 1-propanol and of 2-propanol with propane-1,2-diol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, or 1-tert-butoxy-2-propanol and water with 1-methoxy-2-propanol or 1-ethoxy-2-propanol. Excess volumes are negative over the whole mole fraction range and rather symmetrical for mixtures with 1-propanol. For the mixtures with 2-propanol and water, excess volumes are also negative over the whole mole fraction range but the curves are slightly unsymmetrical. The results are discussed on the basis of molecular interactions between the components of the mixtures.

Excess volumes of (a polar liquid + an aromatic hydrocarbon) at the temperature 298.15 K. V. (γ-Butyrolactone + an aromatic hydrocarbon)

Excess molar volumes have been measured by means of a continuous dilution dilatometer for (γ-butyrolactone + benzene, or toluene, or o-xylene, or m-xylene, or p-xylene, or ethylbenzene, or styrene) at T= 298.15 K. The V m Evalues are negative over the entire range of composition for all the binary mixtures. The ∣ V m E(minimum)∣ and ∣ V m E( x= 0.5)∣ values of this series decrease in the sequence: C 6H 5CH=CH 2> C 6H 5CH 3> C 6H 6> p-C 6H 4(CH 3) 2> C 6H 5CH 2CH 3≈ m-C 6H 4(CH 3) 2> o-C 6H 4(CH 3) 2. The results were compared with the results for binary mixtures containing other polar liquids, and showed that the interactions between γ-butyrolactone molecules and the above-noted aromatic hydrocarbon molecules are very strong.

Excess molar volumes of binary mixtures of some aliphatic amines with selected members of homologous series of n-alkanes at T= 298.15 K

Excess molar volumes of binary liquid mixtures of (heptane or octane or dodecane + n-hexylamine or diethylamine or di- n-propylamine) at T= 298.15 K, measured with a tilting dilution dilatometer, are reported. The excess volumes are positive over the entire concentration range for all mixtures and increase with increasing length of the n-alkane molecule for mixtures containing n-hexylamine and di- n-propylamine, while the maximum is observed for mixtures of ( n-alkane + diethylamine).

Excess volumes of (N-methylformamide + ethanol + water) at the temperature 313.15 K

Excess molar volumesVmEmeasured at the temperatureT= 313.15 K in a dilution dilatometer are reported for the binary mixture (N-methylformamide + ethanol) and for the ternary mixture (N-methylformamide + ethanol + water). The results have been analysed using various correlation equations. The results for (N-methylformamide + ethanol) are compared with previously obtained data for (N-methylformamide + A) (where A = water and methanol) and for (N,N-diemthylformamide + B) (where B = water, methanol, ethanol, and propan-1-ol). From this comparison, it is suggested that the difference in molecular sizes of both components of the binary mixture (amide + A) play an important role in determining theVmEvalues.

Excess volumes in ( N-methylformamide + methanol + water) at the temperature 313.15K

Excess volumes V Emeasured at the temperature 313.15K in a dilution dilatometer are reported for the binary mixtures ( N-methylformamide + water) and ( N-methylformamide + methanol) and for the ternary mixture ( N-methylformamide + methanol + water). The results have been analysed using various correlation equations.

A computer controlled continuous dilution dilatometer for the determination of solute molar volumes and direct measurement of reaction volumes in solution

The design and operation of a computer controlled continuous dilution dilatometer utilizing a diode array detection system is presented. To test the accuracy and reproducibility of the technique, apparent molar volumes of dilute aqueous solutions of potassium ferricyanide and potassium ferrocyanide have been measured. To provide supporting data for high pressure studies of reaction volumes and molar volume change in solutions of high ionic strength, study of these electrolytes was extended by dilution into 0.1M and 1.0M potassium nitrate solutions rather than extrapolation to zero ionic strength as is normal. In addition, the system has been used to determine reaction volumes of some acid-base reactions by direct measurement, using the equipment as an automatic titration dilatometer.