Article

Surface tensions and refractive indices of (tetrahydrofuran +n -alkanes) atT =298.15 K

Departamento de Fı́sica Aplicada, Facultad de Fı́sica, Universidad de Santiago, E-15706, Santiago de Compostela, Spain
The Journal of Chemical Thermodynamics 01/1999; DOI: 10.1006/jcht.1999.0517

ABSTRACT The refractive indices n and surface tensions σ of liquid binary mixtures {xc-(CH2)4O + (1 − x)CH3(CH2)mCH3,m = (4 to 8)} were measured at T = 298.15 K over the whole concentration range. The densities ρ of {xc-(CH2)4O + (1 − x)CH3(CH2)8CH3} were also measured at this temperature. The data are discussed in terms of molecular interactions and the chain length of the n -alkane. The Lorentz–Lorenz, Dale–Gladstone, Eykman, Oster, Arago–Biot, and Newton equations were used to predict the excess molar volumes from the refractometric measurements, as well as a modified Eykman equation with a parameter obtained for each binary system from data for dn / dT , dρ / dT , and ρ for the pure components. The most accurate predictions were those of the Oster and parametrized Eykman equations. Surface tensions predicted from measured densities using the Sugden equation and the assumption of mole-wise additivity for parachor were more accurate (between 2 per cent and 7 per cent) than predictions based on refractive index obtained by combining the Sugden equation and the definition of molar refraction R and adopting the additional assumption of mole-wise additivity forR .

0 Bookmarks
 · 
141 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Chemical Papers- Slovak Academy of Sciences 05/2008; 62(3):302-312. · 0.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Certain combustion engine technologies can imply the formation of a liquid film on the walls of the combustion chamber, which produces significant pollutant emission. In this context, experimental study of the flame/film interaction is necessary, which in turn necessitates the measurement of the liquid film thickness. For this purpose, a low-coherence interferometry technique has been used in a specific configuration involving reactive flow and, consequently, temperature gradients, which contribute to measurement errors because of the thermo-optic coefficient. In the present work, in order to estimate these errors, the group refractive indexes of hexane, heptane and octane were measured by low-coherence interferometry according to the temperature at a wavelength of 1310 nm. The comparison of the thermo-optic coefficients indicated a good concordance between experimental data and the application of models derived from electromagnetic theory. The knowledge of these coefficients permits the estimation of a fairly reasonable film thickness uncertainty.
    Experimental Thermal and Fluid Science. 01/2010;
  • Chemical Engineering & Technology - CHEM ENG TECHNOL. 01/2008; 31(3):426-432.