ISSN:
1572-8927
Keywords:
Solubility
;
enthalpy of solution
;
heat capacity
;
volume
;
compressibility
;
sound velocity
;
benzene and 2-propanol
;
microemulsions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The solubilities, enthalpies of solution, heat capacities, densities and ultrasonic velocities of benzene in 2-propanol-water mixtures were measured at 25°C. The apparent molal volumes, heat capacities and isentropic compressibilities and the free energies, enthalpies and entropies of transfer of benzene were calculated. The benzene concentration is sufficiently low that all thermodynamic quantities can be considered in the standard state. All these functions show large changes in the aqueous end. Large extrema are observed for 2-propanol mole fractions (XP) near 0.08, and at higher XP the functions rapidly tend to the values in pure 2-propanol. The free energy of transfer of benzene from water to alcohol-water mixtures decreases linearly with the alcohol concentration up to XP of 0.07 and then more abruptly. On the other hand, at low temperature, this free energy becomes positive at low XP. These data are consistent with the existence of microphases in 2-propanol-water mixtures for Xp〉0.1. At low XP benzene is in an aqueous medium but beyond this critical region dissolves preferentially in the organic microphases. Benzene also enhances the formation of 2-propanol microphases and this leads to the observed extrema near Xp=0.08.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00647035
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