The thermodynamics of associated mixtures. Part 1.—Dioxan+chloroform

Abstract

Vapour pressures and heats of mixing have been measured for mixtures of dioxan (A) and chloroform (B) at SO" C. The results have been satisfactorily interpreted by assuming the existence of the four species A, AB, A B 2 and B in mutual equilibrium and by further assuming that these four species mix ideally. Values are given for the equilibrium constants and heats of formation of AB and AB2.Several systems, such as ether + chloroform and acetone + chloroform, in which the formation of a complex of type AB is believed to occur through the formation of a hydrogen bond between the hydrogen of the chloroform and the oxygen of the other molecule, have been made the subjects of thermodynamic study.1-5 However, we know of no previous thermodynamic investigation of a liquid mixture in which any other type of complex formation would be expected.

Thermodynamic Properties of Cyclopentanol + p-Dioxane Mixtures at 25 °C

“…Negative excess enthalpies have also been reported for mixtures of p-dioxane with carbon tetrachloride (21) and benzene (22) but positive values were observed with cyclohexane (20,23). The excess Gibbs free energy is negative for mixtures of p-dioxane with chloroform (19) and positive for mixtures with water (20), carbon tetrachloride (24), benzene (24), and cyclohexane (20). It appears from these findings that the tendency for p-dioxane to form a complex with other molecular species depends very much on the nature of the other s~ecies.…”

“…It appears from these findings that the tendency for p-dioxane to form a complex with other molecular species depends very much on the nature of the other s~ecies. Chemical association theories have been fairly successful in explaining the thermodynamic behavior of mixtures ofp-dioxane with chloroform (19), benzene (24), and carbon tetrachloride (24). In all of these systems there is a strong interaction between unlike species in the mixture and the excess entropy is negative; in some cases the existence of a stable compound has been confirmed by solid-liquid phase diagrams (25,26).…”

Thermodynamics of chloroform and methanol mixtures

“…Perhaps associated complexes of the general formula AiB, and B, are present in these mixtures. H E and GE data for this mixture were next analysed in terms of the ideal associated model (26,27). It is assumed that in a binary solution of chloroform (A) and methanol (designated as B, since methanol is self-associated) mutual equilibrium of the species A,,B, ABk, and B, ( I = 1, 2, 3, ..., 1; k = l , 2 , 3 ,..., k ; n = l , 2 , 3 ,..., n ; m = 2 , 3 ,..., m) exist according to the reactions so that the equilibrium constants for the various association reactions represented by reaction [3] are and where a denotes activities.…”

“…It is assumed that in a binary solution of chloroform (A) and methanol (designated as B, since methanol is self-associated) mutual equilibrium of the species A,,B, ABk, and B, ( I = 1, 2, 3, ..., 1; k = l , 2 , 3 ,..., k ; n = l , 2 , 3 ,..., n ; m = 2 , 3 ,..., m) exist according to the reactions so that the equilibrium constants for the various association reactions represented by reaction [3] are and where a denotes activities. If the activity coefficients of the various species represented in reaction [3] are assumed to be unity (26)(27)(28)(29), the material balance equation for the system can be written as [7 I + a~, , + CmKm,l lnaAmaB,lin + CkKl ,klna4aB,kln + C l~l l n a B , l i n = 1 Two simple cases were next considered.…”

Thermodynamics of molecular interactions in aniline + benzene mixtures

“…The HE data for this mixture were then analysed in terms of the ideal associated model (17,18). It is assumed that in a binary solution of aniline + benzene mutual equilibrium of the species A,B,, A,,Bx, and B, occurs.…”