<i>PVTx</i>and Isochoric Heat Capacity Measurements for Aqueous Methanol Solutions

Aliev, M. M.; Magee, Joseph W.; Abdulagatov, Ilmutdin M.

doi:10.1023/b:ijot.0000004093.20692.dc

Cited by 16 publications

(13 citation statements)

References 32 publications

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“…The application was tested on a set of 270 zeotropic and azeotropic systems of homogeneous binary solutions and 30 non‐homogeneous systems. In addition to the VLE data, values of the excess properties ( v E and h E ) have been used and, also, LLE data of the system studied, extracted from the literature,…”

Section: Results Of the Testmentioning

confidence: 99%

A rigorous method to evaluate the consistency of experimental data in phase equilibria. Application to VLE and VLLE

2017

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This work forms part of a broader study that describes a methodology to validate experimental data of phase equilibria for multicomponent systems from a thermodynamic‐mathematical perspective. The goal of this article is to present and justify this method and to study its application to vapor–liquid equilibria (VLE) and vapor–liquid–liquid equilibria (VLLE), obtained under isobaric/isothermal conditions. A procedure based on the Gibbs‐Duhem equation is established which presents two independent calculation paths for its resolution: (a) an integral method and (b) a differential method. Functions are generated for both cases that establish the verification or consistency of data, δψ for the integral test and δζ for the differential approach, which are statistically evaluated by their corresponding average values [ δtrueψ¯, δtrueζ¯], and the standard deviations [ strue(δψtrue), strue(δζtrue)]. The evaluation of these parameters for application to real cases is carried out using a set of hypothetical systems (with data generated artificially), for which the values are adequately changed to determine their influence on the method. In this way, the requirements of the proposed method for the data are evaluated and their behavior in response to any disruption in the canonical variables (p,T, phase compositions). The conditions for thermodynamic consistency of data are: δtrueψ¯<2, strue(δψtrue)<0.2, δtrueζ¯<5, and s(δξ)<0.2. In systems with VLLE, in addition to the previous criteria, must occur that: δxLLE<0.05 and δTLLE<0.5 K. The new proposed method has been tested with a set of 300 experimental binary systems, biphasic and triphasic, obtained from published bibliography, and the results are compared with those of other tests commonly used for testing thermodynamic consistency. The results show that the greater rigor of the proposed method is mainly due to the simultaneous verification of various independent variables. As a result, the conditions for the new test are verified for fewer systems than using other tests mentioned in the literature (i.e., Fredenslund‐test and direct of Van Ness). Its unique application is sufficient to ensure the consistency of experimental data, without using other tests. © 2017 American Institute of Chemical Engineers AIChE J, 2017

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Section: Results Of the Testmentioning

confidence: 99%

A rigorous method to evaluate the consistency of experimental data in phase equilibria. Application to VLE and VLLE

2017

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“…Recently they are also used in solar thermal systems . Physical chemists have been attracted by their eccentric, unusual nonideal behavior, especially in the low concentration range . Water and methanol have been proposed as green solvents for conversion of biomass, biodiesel production, and chemical recycle of monomers via depolymerization .…”

Section: Introductionmentioning

confidence: 99%

“…27 Physical chemists have been attracted by their eccentric, unusual nonideal behavior, especially in the low concentration range. 28 Water and methanol have been proposed as green solvents for conversion of biomass, 29 biodiesel production, 30 and chemical recycle of monomers via depolymerization. 31 Some of these processes use supercritical water and others use supercritical methanol.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of Na⁺–Cl^– Ion-Pair in Water–Methanol Mixtures under Supercritical and Ambient Conditions

2015

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Constrained molecular dynamics simulations have been performed to investigate the structure and thermodynamics of Na(+)-Cl(-) ion-pair association in water-methanol mixtures under supercritical and ambient conditions in dilute solutions. From the computed potentials of mean force (PMFs) we find that contact ion pairs (CIPs) are more stable than all other associated states of the ion pairs in both ambient and supercritical conditions. Stabilities of CIPs increase with increase in the mole fraction of methanol. In supercritical conditions, major changes in PMFs occur as we go from x(methanol) = 0.00 to x(methanol) = 0.50. The stable solvent shared ion pair (SShIP) which occurs in x(methanol) = 0.00 and 0.25, vanishes when x(methanol) is 0.50 or greater. The stabilities of these ion pairs increase with increasing temperature. Local structures around the ions are studied using the radial distribution functions, density profiles, angular distribution functions, running coordination numbers and excess coordination numbers. Preferential solvation analysis shows that both Na(+) and Cl(-) ions are preferentially solvated by water. From the calculation of enthalpies and entropies, we find that Na(+)-Cl(-) ion-pair association in water-methanol binary mixtures is endothermic and driven by entropy both in ambient as well as under supercritical conditions.

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“…From the technological point of view, such mixtures have served as useful industrial solvent media for a variety of separation processes; moreover, recently it has become popular to use them also in solar thermal systems [1]. Physical chemists have been attracted by their eccentric, unusual non-ideal behavior, especially in the low concentration range [2]. Aqueous solutions of alcohols are also ones of the simplest aqueous solutions with the solute having both a hydrophilic head and hydrophobic tail.…”

Section: Introductionmentioning

confidence: 99%

Excess properties of aqueous mixtures of methanol: Simulation versus experiment

González-Salgado¹,

Nezbeda²

2006

Fluid Phase Equilibria

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PVTxand Isochoric Heat Capacity Measurements for Aqueous Methanol Solutions

Cited by 16 publications

References 32 publications

A rigorous method to evaluate the consistency of experimental data in phase equilibria. Application to VLE and VLLE

A rigorous method to evaluate the consistency of experimental data in phase equilibria. Application to VLE and VLLE

Molecular Dynamics Simulation of Na⁺–Cl^– Ion-Pair in Water–Methanol Mixtures under Supercritical and Ambient Conditions

Excess properties of aqueous mixtures of methanol: Simulation versus experiment

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PVTxand Isochoric Heat Capacity Measurements for Aqueous Methanol Solutions

Cited by 16 publications

References 32 publications

A rigorous method to evaluate the consistency of experimental data in phase equilibria. Application to VLE and VLLE

A rigorous method to evaluate the consistency of experimental data in phase equilibria. Application to VLE and VLLE

Molecular Dynamics Simulation of Na+–Cl– Ion-Pair in Water–Methanol Mixtures under Supercritical and Ambient Conditions

Excess properties of aqueous mixtures of methanol: Simulation versus experiment

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Product

Resources

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Molecular Dynamics Simulation of Na⁺–Cl^– Ion-Pair in Water–Methanol Mixtures under Supercritical and Ambient Conditions