Thermodynamics of the Ternary Mixture Propan‐1‐ol + Triethylamine + n‐Heptane. Experimental Results and ERAS‐Model Calculations of H^E and V^E

Abstract

Equations of State J Hydrogen Bonding J Liquids J Solutions J ThermodynamicsMolar excess enthalpies (HE) and molar excess volumes (VE) of the liquid mixture Propan-1-01 (PrOH) + Triethylamine (TEA) + n-Heptane have been measured by flow calorimetry and the vibrating tube technique respectively. Data of the three binary systems have also been obtained. The excess properties are dominated by strong hydrogen bondings due to the self-association of PrOH and the association of PrOH with TEA. The third component, heptane, serves mainly as an inert diluting solvent. H E and VE are positive for PrOH + heptane and also for TEA + heptane to a much smaller extent. Strongly negative values of both HE and VE have been obtained for PrOH + TEA. The values obtained for the ternary system lie in between these extreme cases showing certain compositions where H E and VE vanish. -An extended version of the so-called ERAS model has been used for describing H E and VE of the complete ternary system. The parameters adjusted to the binary data reveal that the hydrogen bonding enthalpies and volumes between PrOH and TEA are distinctly stronger than between self-associating PrOH molecules. In addition the widely applied NRTL-model has also been used for describing H E of the ternary systems. VE, however, can not be calculated with the NRTL model. Ber. Bunsenyes. Phys. Chum. YS ( / W / ) No. 7 VCH Verlaysgesellschafi mbH. W-6940 Weinheim. 1991 OOOS-WZl~9l~0707-08~/ $ 3.50+ .ZSjO

Thermodynamics of mixtures with strongly negative deviations from Raoult’s law. Part 8. Excess molar volumes at 298.15K for 1-alkanol + isomeric amine (C6H15N) systems

“…Our data for the 1-propanol + TEA system are in good agreement with values previously published [24,36] ( Table 2; Fig. 1).…”

“…At this end, we report V E data at 298.15 K and atmospheric pressure for mixtures of methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol or 1-octanol with HxA and of 1-propanol, 1-pentanol, 1-hexanol, 1-heptanol or 1-octanol with TEA. Moreover, we test the ability of the ERAS model [11] to represent simultaneously, for the mentioned systems, our V E values and the H E measurements available in the literature [20,[22][23][24][25].…”

“…The extremely negative H E values [16][17][18][19][20][21][22][23][24][25] of these systems are interpreted in terms of two opposing effects [4,18,21]: (a) in the pure state, both, the alcohol and the amine are self-associated by the formation of O-H · · · O and N-H · · · N bonds, respectively. The disruption of these bonds upon mixing leads to a positive contribution to H E ; (b) strong intermolecular interactions between the hydroxyl and amine groups contribute negatively to H E .…”

Densities of (2-butanol +n-hexane + 1-butylamine) atT= 298.15 andT= 313.15 K: excess and partial excess molar volumes and application of the ERAS model

“…The expressions of V E for multicomponent mixtures can be found elsewhere. (46,47) (48) for a mixture of an associated compound and an alkane was used. For these mixtures X i j is the only adjustable parameter and is obtained from the literature excess enthalpies.…”

Excess enthalpies of (α-methylstyrene + methanol, or ethanol, or propan-1-ol)

“…The so-called ERAS model provides a promising concept (5) which has already been applied to different (alkanols + hydrocarbons), (5,7,8) (alkanols + amines), (9)(10)(11) and (alkanols + ethers), (12,13) and will be used in a forthcoming study for treating the systems investigated experimentally here. …”