Digital Density Meter Research Articles

Excess Properties of Binary Mixtures of Esters of Carbonic Acid + Three Aryl Alcohols at 308.15 K

Excess molar enthalpies, , and excess molar volumes, , of binary mixtures containing dimethyl carbonate, or diethyl carbonate, or propylene carbonate + benzyl alcohol, + 2-phenylethyl alcohol, and + 3-phenyl-1-propyl alcohol have been studied over the entire range of composition at 308.15 K and at atmospheric pressure using a flow microcalorimeter and a digital density meter. The values are positive, increasing as the chain length of aryl alcohol increases and showing a maximum varying from 1040 J·mol-1 (diethyl carbonate + benzyl alcohol) up to 1730 J·mol-1 (dimethyl carbonate + 3-phenyl-1-propyl alcohol). values are negative or positive with no definite trend. The mixture containing propylene carbonate + 2-phenylethyl alcohol shows an inversion of sign. All curves for mixtures containing dimethyl carbonate and diethyl carbonate are quasi-symmetrical, whereas those containing propylene carbonate are asymmetrical. Results were fitted to the Redlich−Kister polynomial. The results are qualitatively discusse...

Thermodynamic Study of Binary Mixtures Containing Glycols or Polyethylene Glycols + Benzyl Alcohol at 308.15 K

Excess molar enthalpies and excess molar volumes of binary mixtures containing ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, or poly(ethylene glycol)s (PEG200, PEG300, PEG400, and PEG600) + benzyl alcohol were determined at 308.15 K and at atmospheric pressure using a flow microcalorimeter and a digital density meter. Results were fitted to the Redlich−Kister polynomial to estimate the binary interaction parameters. The results are interpreted in terms of molecular interactions between the components.

Densities, Viscosities, and Refractive Indices of Binary Mixtures Containing n-Hexane + Components of Pine Resins and Essential Oils at 298.15 K

Densities, ρ, viscosities, η, and refractive indices, nD, of binary mixtures containing n-hexane + α-pinene (2,6,6-trimethylbicyclo[3.1.1]hept-2-ene), + β-pinene (6,6-dimethyl-2-methylene bicyclo[3.1.1]heptane), + p-cymene (1-methyl-4-[1-methylethyl]benzene), + (S)-(−)-limonene [(−)-1-methyl-4-(1-methylethenyl)cyclohexene], + 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane), and + linalool (3,7-dimethyl-1,6-octadien-3-ol) were determined at 298.15 K and at atmospheric pressure using a digital density meter, a Schott viscosity measuring system, and an Abbe refractometer, respectively. The excess molar volumes, , deviations in viscosities, Δη, and deviations in molar refractions, ΔR, calculated from experimental measurements, are always negative, with the exception of the curve referring to the hexane + linalool mixture, which shows an inversion of sign. Results were fitted to the Redlich−Kister polynomial and qualitatively discussed in terms of molecular interactions. The McAllister multibody intera...

Densities, Viscosities, Refractive Indices, and Excess Molar Enthalpies of Methyl tert-Butyl Ether + Components of Pine Resins and Essential Oils at 298.15 K

Densities, ρ, viscosities, η, refractive indices, nD, and excess molar enthalpies, , of binary mixtures containing methyl tert-butyl ether (MTBE) + α-pinene (2,6,6-trimethylbicyclo[3.1.1]hept-2-ene), + β-pinene (6,6-dimethyl-2-methylenebicyclo[3.1.1]heptane), + p-cymene [1-methyl-4-(1-methylethyl)benzene], + (S)-(−)-limonene [(−)-1-methyl-4-(1-methylethenyl)cyclohexene], + 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane), and + linalool (3,7-dimethyl-1,6-octadien-3-ol) were determined at 298.15 K and at atmospheric pressure using a digital density meter, a Schott measuring system, an Abbe refractometer, and a flow microcalorimeter, respectively. The excess molar volumes, , the deviations in viscosities, Δη, and in refractive indices, ΔR, and the excess molar enthalpies, , were calculated from experimental measurements. Results were fitted to the Redlich−Kister equation to obtain the adjustable parameters and standard deviations. Results were also qualitatively discussed in terms of molecular intera...

Densities, Viscosities, and Excess Molar Enthalpies of Binary Mixtures Containing Essential Oils at (298.15 and 313.15) K. The (S)-(−)-Limonene + Cineole, (S)-(−)-Limonene + Linalool, and Cineole + Linalool Systems

Densities, ρ, viscosities, η, and excess molar enthalpies, , of binary mixtures containing (S)-(−)-limonene [(−)-1-methyl-4-(1-methylethenyl)cyclohexene] + 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2,2,2]octane), (S)-(−)-limonene + linalool (3,7-dimethyl-1,6-octadien-3-ol), and cineole + linalool were determined at (298.15 and 313.15) K and at atmospheric pressure using a digital density meter, a Schott measuring system, and a flow microcalorimeter, respectively. The excess molar volumes, , the viscosity deviations, Δη, and the 's were calculated from experimental measurements. Results were fitted to the Redlich−Kister polynomial to obtain the adjustable parameters and standard deviations. Results were also qualitatively explained in terms of molecular interactions.

Excess Molar Enthalpies and Excess Molar Volumes of Binary Mixtures Containing 1,3-Dioxolane or 1,4-Dioxane + Pine Resins at (298.15 and 313.15) K and at Atmospheric Pressure

Excess molar enthalpies, , and excess molar volumes, , of binary mixtures containing 1,3-dioxolane or 1,4-dioxane + α-pinene, + β-pinene, or + p-cymene were determined at (298.15 and 313.15) K and at atmospheric pressure over the entire composition range using a flow microcalorimeter and a digital density meter. and are always positive, and the temperature dependence is more marked for values. Results were fitted to the Redlich−Kister polynomials to obtain the binary adjustable parameters and the standard deviations

Excess Molar Enthalpies and Excess Molar Volumes of Binary Mixtures Containing Dialkyl Carbonates + Pine Resins at (298.15 and 313.15) K

Excess molar enthalpies, , and excess molar volumes, , of binary mixtures containing dimethyl carbonate (DMC), or diethyl carbonate (DEC) + α-pinene, + β-pinene, or + p-cymene have been determined using a flow microcalorimeter and a digital density meter at atmospheric pressure and at (298.15 and 313.15) K. All and data are positive and show symmetrical curves versus composition. The influence of temperature is marked for volumetric measurements while almost negligible for enthalpic data. Results have been correlated using the Redlich−Kister polynomial to estimate the binary interaction parameters. The calculated quantities have been qualitatively discussed in terms of thermodynamic interactions between the mixing compounds.

Wax deposition from Middle East crudes

This paper reports measurements of wax content by acetone precipitation techniques as well as wax appearance temperature (WAT) by viscosity measurements and differential scanning calorimetry (DSC) of eight different stock-tank crude oils from the Middle East. Comparison of WAT measured by DSC and viscosity indicates that the viscosity method overestimates the WAT. Crude oil gravity measured, by digital density meter, and molecular weight, by vapor pressure osmometer, were used to characterize the plus fraction and predict WAT and amount of wax formed at a given condition by the thermodynamic model. Comparison between predicted and measured results shows that measured WAT by DSC compares very well with that predicted from the model for most crudes. Generally, wax contents measured by the modified UOP method 46-64 and that predicted by the thermodynamic model are in good agreement.

Densities and apparent molar volumes for aqueous solutions of HNO3−UO2(NO3)2 at 298.15 K

In order to obtain the exact information of atomic number density in the ternary system of HNO3−UO2(NO3)2−H2O, the densities were measured with an Anton-Paar DMA60/602 digital density meter thermostated at 298.15±0.01 K. The apparent molal volumes for the systems were calculated from the experimental data. The present measured apparent molar volumes have been fitted to the Pitzer ion-interaction model, which provides an adequate representation of the experimental data for mixed aqueous electrolyte solutions up to 6.2 mol/kg ionic strength. This fit yields θV, and ψV, which are the first derivatives with respect to pressure of the mixing interaction parameters for the excess free energy. With the mixing parameters θV, and ψV, the densities and apparent molar volumes of the ternary system studied in this work can be calculated with good accuracy, as shown by the standard deviations.

Excess Molar Enthalpies and Excess Molar Volumes of Binary Mixtures Containing Dimethyl Carbonate + Four Butanol Isomers at (288.15, 298.15, and 313.15) K

Excess molar enthalpies, , and excess molar volumes, , of dimethyl carbonate + 1-butanol, + 2-butanol, + 2-methyl-1-butanol, and + 2-methyl-2-butanol have been determined at (288.15, 298.15, and 313.15) K and atmospheric pressure using a flow microcalorimeter and a digital density meter. Excess properties are positive over the entire experimental conditions, increasing as the temperature increases. Maxima values of vary from 2100 up to 2900 J·mol-1. Those of vary from 0.57 up to 0.83 cm3·mol-1. Experimental data have been correlated using Redlich−Kister polynomials, and parameters from least-squares analysis have been reported.

Excess Molar Enthalpies and Excess Molar Volumes of Dimethyl Carbonate + Seven Alkyl Acetates at 298.15 K

Excess molar enthalpies and excess molar volumes of dimethyl carbonate + seven alkyl acetates have been determined at 298.15 K and at atmospheric pressure using a flow microcalorimeter and a digital density meter. Values of excess enthalpies and excess volumes increase as the chain length of the acetate molecule is increased. In contrast, the mixtures containing dimethyl carbonate + vinyl acetate show the lowest values. The experimental results have been correlated using the Redlich−Kister equation and have been qualitatively discussed.

Excess Molar Enthalpies and Excess Molar Volumes of Dialkyl Carbonates + Acetic or Propionic Acid at 298.15 K

Excess molar enthalpies, H m E , and excess molar volumes, V m E , of the binary mixtures of dimethyl carbonate or diethyl carbonate + acetic acid or propionic acid have been determined at 298.15 K as a function of composition using a flow microcalorimeter and a digital density meter. Excess values have been correlated with the Redlich-Kister equation, and smoothed data plots are presented.

Excess molar enthalpies, densities and excess molar volumes for binary mixtures containing dimethyl carbonate or diethyl carbonate + 2,2,4-trimethylpentane at 288.15, 298.15, and 313.5 K, and at atmospheric pressure. Application of an extended cell model

Excess molar enthalpies, H E m, densities, ϱ, and excess molar volumes, V E m, of dimethyl carbonate or diethyl carbonate + 2,2,4-trimethylpentane have been determined at 288.15, 298.15 and 313.15 K and at atmospheric pressure, using an LKB flow microcalorimeter and an Anton Paar digital density meter. For all mixtures, the H E m and V E m values are positive and increase slowly as the temperature is increased. The experimental values have been correlated by the Redlich-Kister equation and the adjustable parameters have been evaluated by least-squares analysis. The results are discussed qualitatively in terms of molecular interactions and have been interpreted by an extended cell model.

Solubility and Density of Chloric Acid + Sodium Chlorate Solutions

Solubilities of sodium chlorate were measured in chloric acid solutions ranging in concentration from 5 to 22 mass % HClO 3 at temperatures of 25, 35, 45, 55, and 65 °C. Densities of saturated solutions were determined by weighing measured volumes of the solutions. Densities of chloric acid solutions and unsaturated chloric acid + sodium chlorate solutions were determined at 25 °C over a range of solution concentrations using a digital density meter. The solubility data and previously reported data from literature sources were correlated with chloric acid concentration and temperature by multilinear regression. All of the data could be represented graphically by a single line by plotting the ratio of sodium chlorate solubility in chloric acid solution to sodium chlorate solubility in water versus mass percent chloric acid. The specific volume of chloric acid at 25 °C is linear with respect to chloric acid concentration. A parameter determined from the slope of this linear plot and the density of crystalline sodium chlorate were used to correlate densities of chloric acid solutions containing sodium chlorate.

Excess Molar Volumes of Binary Mixtures Containing Diethyl Carbonate + Linear and Cyclic Ethers at 298.15 K

Densitites and excess molar volumes for the eight binary mixtures diethyl carbonate + diethoxymethane, + 1,2-diethoxyethane, + dimethoxymethane, + 1,2-dimethoxyethane, + 1,3-dioxolane, + oxolane, + 1,4-dioxane, or + oxane have been determined at 298.15 K and atmospheric pressure by means of a digital density meter. Excess molar volumes are negative over the entire range of composition for the four mixtures containing linear ethers and positive in the cases of cyclic ethers with the exception of the diethyl carbonate + 1,3-dioxolane mixture, which presents a sign inversion. The results were correlated by the Redlich-Kister equation.

Excess Molar Enthalpies and Excess Molar Volumes of Propylene Carbonate + Cyclic Ethers

Excess molar enthalpies, H m E , and excess molar volumes, V m E , have been determined as a function of mole fraction for propylene carbonate+oxane, oxolane, 1,4-dioxane, and 1,3-dioxolane at 298.15 K and at atmospheric pressure in a flow microcalorimeter and in a digital density meter. The experimental values have been correlated using the Redlich-Kister equation, and the parameters have been evaluated by least-squares analysis. The H m E values are positive for the propylene carbonate+oxane and oxolane mixtures and negative in the mixture with 1,3-dioxolane, while an inversion of sign has been noted for the propylene carbonate+1,4-dioxane mixture

Excess molar volumes of binary mixtures containing isooctane + six methyl- n-alkyl ketones at 298.15 K

Excess molar volumes V E of binary mixtures containing isooctane + six methyl- n-alkyl ketones have been determined using a digital density meter at 298.15 K and atmospheric pressure. The experimental values were correlated by the Redlich-Kister equation. V E decreases with an increase in the chain length of the ketone, from the highly positive values of isooctane + 2-propanone ( V E ≈ 1.0cm 3mol −1) up to the markedly negative values of isooctane + 2-undecanone ( V E ≈ −0.4cm 3 mol −1). The volume effect is discussed qualitatively in terms of the molecular interactions.

Excess molar volumes of ethylbenzene and (2-chloroethyl)benzene + five methyl n-alkyl ketones at 298.15 K

Excess molar volumes V m E of ethylbenzene and (2-chloroethyl)benzene+five methyl n-alkyl ketones have been determined from density measurements at 298.15 K and atmospheric pressure by means of an Anton Paar digital density meter. Values of V m E are negative for all mixtures with the exception of the (2-chloroethyl)-benzene+2-undecanone system which presents an inversion of sign. The variation of V m E with molecular size is discussed

Excess molar enthalpies and excess molar volumes of binary mixtures containing p-xylene + cyclic ethers

Excess molar enthalpies H E, and excess molar volumes V E, of mixturesof p-xyleae with the cyclic ethers oxolane, oxane, 1,3-dioxolane, and 1,4-dioxane have been determined by means of a flow microcalorimeter and a digital density meter at 298. 15″ K and afinospheric pressure. The experimental values are correlated by polynomiah equations. V E is positive over the entire range of mole fractions for p-xylene-1,4-dioxane, but is negative for the other mixtures. H E is positive for the mixtures involving the diethers-1,3-dioxolane and 1,4-dioxane, and negative for the monoethers. The heat effects are qualitatively discussed in terms of molecular interactions.

Pressure dependence of the density of n-alkanes

Accurate density data for n-alkanes are essential for the measurement of interfacial tension of liquid-liquid systems as a function of pressure. The variation of density with pressure for three n-alkanes, n-hexane, n-heptane, and n-decane, was measured at 21.2°C and pressures ranging from 0.1 to 35 MPa with a digital density meter. The Tait equation of the form (ρ−ρ0)/ρ=C log[(B+P)/ (B+P0)] was used to represent the experimental data.