Excess Properties of Some Methanol + Amide Systems Proposed as Working Fluids for Absorption Machines

Abstract

Excess enthalpies and excess volumes of the binary systems methanol + N-formylmorpholine, methanol + N-methyl-2-pyrrolidine, and methanol + 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone at 298.15 K and atmospheric pressure have been measured. Excess enthalpies H E were measured in a Calvet microcalorimeter and excess volume V E in a vibrating-tube densimeter. All the V E values were negative, and the H E values were also negative except those of the methanol + N-formylmorpholine system. The results are discussed qualitatively in terms of molecular interactions. A version of the UNIFAC group contribution model has been used to compare the predicted and experimental H E results.

Isothermal Vapor−Liquid Equilibrium and Excess Enthalpy Data for the Binary Systems Water + Sulfolane and Methanol + N-Methyl-2-pyrrolidone

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6 Experimental and predicted excess enthalpy data for the system methanol (1) + N -methyl-2-pyrrolidone (2): ◇, this work at 393.15 K; ○, Sitnyakovsky et al at 298.15 K; □, Joly and Mermet-Dupin 5 at (298.15 and 308.15) K; ▵, Murakami et al . at 298.15 K; +, Burgdorf 3 at (298.15 and 353.15) K; ×, Lopez et al at 298.15 K; solid line, NRTL; dashed line, Mod. UNIFAC (Do).

7 Experimental and predicted activity coefficients at infinite dilution of methanol in N -methyl-2-pyrrolidone: ◇, Weidlich et al; ○, Sitnyakovsky et al; □, Shaposhnikov and Lichotkin; ▵, Rajeshwar Rao and Bhagat; +, Rajeshwar Rao and Bhagat; solid line, NRTL; dashed line, Mod.

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“…Excess enthalpy data are important to describe the temperature dependence of the activity coefficients following the Gibbs−Helmholtz equation The experimental data of this work are presented in comparison to the results of the other authors, − calculations using the parameters for the nonrandom two-liquid (NRTL) model obtained by a simultaneous correlation of all experimental data (VLE, H E , and activity coefficients at infinite dilution), and the predictions using the group contribution method Mod. UNIFAC (Do). − …”

Thermodynamic properties of mixtures of N-methyl-2-pyrrolidinone and methanol at temperatures between 298.15K and 343.15K and pressures up to 60MPa

“…This completed one predictor-corrector step and established all of the thermodynamic properties along the isobar at p = p 1 with temperature spacing dT. The density values at p = p 1 were then fitted by equation (6) and the process restarted with p 1 as the initial pressure. These steps were repeated sequentially until the desired upper pressure limit was reached.…”

“…Various thermodynamic properties of (NMP + alkanol) have been reported over a wide range of temperatures at ambient pressure [2][3][4][5][6][7][8], and the density has been measured at elevated pressure [9]. The system is highly non-ideal, no doubt as a result of specific interactions and differences in molecular size and shape.…”

PVTx Measurements of the N-Methylpyrrolidone/Methanol Mixed Solvent: Cubic and SAFT EOS Analyses

“…The excess enthalpy of the NMP/methanol system is strongly negative; the minimum value = − 660 J mol -1 at x = 0.5 denotes that the NMP-methanol heteroassociations become partly balanced by the endothermic contributions arising from the disruptions of the alcohol and NMP structures, giving rise to a global exothermic mixing process. The pressure effect on the excess Gibbs energy, excess enthalpy, and excess entropy at constant temperature is somewhat more complex.…”