Phase Equilibria of (Pyrrole + Benzene, Cyclohexane, and Hexane) and Density of (Pyrrole + Benzene and Cyclohexane) Binary Systems

Abstract

The phase diagrams of pyrrole with benzene, cyclohexane, and hexane have been measured at ambient pressure by a dynamic method in a range of temperatures from (240 to 315) K. The simple eutectic system was observed with complete miscibility in the liquid phase for benzene. An immiscibility gap has been observed in the systems of {pyrrole (1) + cyclohexane or hexane (2)}. The upper critical solution temperatures (UCSTs) were observed for these two systems at (285.2 and 314.2) K for cyclohexane and hexane, respectively. The diagrams of phase equilibria have been correlated using the Wilson and the nonrandom two-liquid (NRTL) equation. The isothermal densities of pyrrole as a function of pressure was measured. Densities and excess molar volumes, V m E have been determined for pyrrole with benzene and cyclohexane over temperature range (298.15 to 338.15) K and ambient pressure. The densities of {pyrrole (1) + hexane (2)} mixture was not determined because of the problem of two phases up to 314.2 K. The temperature and composition dependences were described by linear or polynomial correlation. Excess molar volumes were calculated and correlated by the Redlich-Kister polynomial expansion. These systems exhibit negative excess molar volumes, V m E . Volume expansivity, R, and excess volume expansivity, R E , were described in functions of temperature and composition. Our experimental data of V m E were used for the description of the excess molar enthalpy, H m E , for these systems with the Prigogine-Flory-Paterson (PFP) model. Negative V m E and H m E observed in these systems are probably attributed to the π-π interactions between the aromatic rings of pyrrole and benzene for the {pyrrole (1) + benzene (2)} mixture and by the high packing effects for the {pyrrole (1) + cyclohexane (2)} mixture. † Part of the "Workshop in Memory of Henry V. Kehiaian".

A Kirkwood–Buff force field for the aromatic amino acids

“…Before adopting the KBFF models it is always prudent to compare results from other force fields and experiment with results obtained using the KBFF for the properties of interest. 76 …”

“… T melt 78 ; Density (ρ): Ben 79 , Tol 36 , PhOH 80 , pCr 81 , Pyrr 39 , Py 82 ; Enthalpy of vaporization (Δ vap H ): Ben 67 , Tol 78 , PhOH 80 , Pyrr 83 , Py 84 ; Isothermal compressibility (κ T ): Ben 85 , Tol 86 , PhOH 78 , pCr 87 , Pyrr 76 , Py 88 ; Isothermal expansion (α p ): Ben 85 , Tol 85 , PhOH 89 , pCr 90 , Pyrr 76 , Py 88 ; Dielectric constant (ε): Ben 91 , Tol 92 , PhOH 80 , pCr 93 , Pyrr 94 , Py 95 …”

“…This was an observation that agreed with other simulations and experiments. [73][74][75][76] However, a rigorous analysis of the percentages or lifetimes of the chain and cyclic structures was not performed. A more thorough discussion of this microstructure can be found in one of our recent publications.…”

“…104 Our model for Ben + MOH does not capture the increase in D t,MOH at low x MOH , but the low simulated values seemed to agree with the presence of MOH-MOH clusters observed in our simulations and by others, [73][74][75]105,106 which one would expect to diminish the rate of diffusion of MOH. The experimental work referenced for the Ben + Tol system describes the diffusion in this system T melt ; 78 Density (r): Ben, 79 Tol, 36 PhOH, 80 pCr, 81 Pyrr, 39 Py; 82 Enthalpy of vaporization (D vap H): Ben, 67 Tol, 78 PhOH, 80 Pyrr, 83 Py; 84 Isothermal compressibility (k T ): Ben, 85 Tol, 86 PhOH, 78 pCr, 87 Pyrr, 76 Py; 88 Isothermal expansion (a p ): Ben, 85 Tol, 85 PhOH, 89 pCr, 90 Pyrr, 76 Py; 88 Dielectric constant (e): Ben, 91 Tol, 92 PhOH, 80 pCr, 93 Pyrr, 94 Py. 95 We note that our results were not corrected for finite size effects, which typically result in 5-10% larger diffusion coefficients.…”

Liquid–Liquid Equilibrium Data for the Ternary Systems of Water, Isopropyl Alcohol, and Selected Entrainers

“…In a past few years, the use of benzene as an entrainer is diminishing with time as benzene is being considered as environmentally hazardous entrainer. Other environment friendly entrainers must be analyzed and utilized in the separation processes. − Hence, an intensive research is being done to find beneficial entrainers to replace benzene. The past literature also provides the phase equilibria of the studied systems, i.e., water–cyclohexane–IPA, − water–hexane–IPA, , and water–benzene–IPA. − In this work, phase equilibrium for the water–PA system is developed by using three entrainers, benzene, cyclohexane, and hexane.…”