Binary Mixtures Of Heptane Research Articles

Surface Tension and Interfacial Tension of Binary Organic Liquid Mixtures

The pendant drop method, combined with efficient temperature control of the measuring cell, allows high precision measurements of both surface tension and interfacial tension. The surface tensions and liquid densities of mixtures of cyclohexane + heptane, cyclohexane + propanone, and toluene + propanone have been determined at a normal pressure of 1 bar over the temperature range from 287 K to 317 K. The surface tension data could be parametrized with a cubic polynomial. Gibbs excess surface concentrations are derived from our experimental data, and the influence of activity coefficients is discussed. The high precision pendant drop apparatus allows accurate measurements of the interfacial tension in systems with liquid−liquid phase separation. In binary mixtures of heptane + N,N-dimethylformamide, heptane + N-methyl-2-pyrrolidone, and decane + N,N-dimethylformamide, the interfacial tension was measured over a wide temperature range close to the critical solution point. The densities of the corresponding ...

Densities and Excess Volumes in Binary Mixtures of Heptane with 1-Chloropropane, 1-Chlorobutane, 1-Chloropentane, or 1-Chlorohexane at 298.15 K

Densities and excess molar volumes, VE, of heptane-1-chloropropane, heptane- 1-chlorobutane, heptane-1-chloropentane, and heptane-1-chlorohexane systems are reported at 298.15 K and atmospheric pressure over the whole composition range. Value of VE was found to be slightly negative at lower mole fractions and slightly positive at higher mole fractions in case of the heptane-1-chlorohexane system. For all the other systems, VE was positive. The VE results were correlated using the fourth-order Redlich-Kister equation, the maximum likelihood procedure being applied for evaluating the adjustable parameters.

Adsorption of binary mixtures of heptane and alkanols by activated carbon

The adsorption isotherm of heptane–hexanol on activated carbon at 298 K is presented and compared with our earlier work on heptane–ethanol and heptane–butanol mixtures under similar conditions. The data show that the preferred adsorption shifts from the alkane to the alkanol as the length of the alkanol chain, relative to that of the alkane chain, increases. The surface mole fraction, interfacial tension differences and surface activity coefficients have been estimated based on an approximate theoretical model (surface phase model). These results show that the minimum thickness of the layers required to achieve thermodynamic consistency between the surface phase model and the experimental data increases as the length of the alkanol chain decreases. All the systems exhibit smaller deviations from ideality in the adsorbed phases than in the bulk.

Isothermal vapor—liquid equilibria for two binary mixtures of heptane with 2-butanone and 4-4-methyl-2-pentanone measured by a dynamic still with a pressure regulation

Abstract Isothermal vapor—liquid equilibrium data are presented for two binary mixtures of heptane with 2-butanone at 45°C and 4-methyl-2-pentanone at 70°C. A control system is connected to a vapor and liquid recirculating still; the recorded fluctuations of still temperature usually have been within ±0.005 K. The data points are consistent according to the local area test. The experimental activity coefficients are compared with those predicted by the UNIFAC method.