Density and partial molar volumes of the liquid mixture water + methanol + ethanol + 2-propanol at 298.15 K and 0.1 MPa [original]

Gabriela Guevara-Carrion, Robin Fingerhut, Jadran Vrabec

Density and partial molar volumes of the liquid

mixture water + methanol + ethanol + 2-propanol

at 298.15 K and 0.1 MPa

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Citation details

Guevara-Carrion, G., Fingerhut, R., Vrabec, J. (2021). Density and Partial Molar Volumes of the Liquid Mixture

Water + Methanol + Ethanol + 2-Propanol at 298.15 K and 0.1 MPa. Journal of Chemical Engineering Data,

66(6), 2425–2435. https://doi.org/10.1021/acs.jced.1c00070

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal

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by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.jced.1c00070.

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Density and partial molar volumes of the liquid

mixture water + methanol + ethanol + 2-propanol

at 298.15 K and 0.1 MPa

Gabriela Guevara-Carrion, Robin Fingerhut, and Jadran Vrabec∗

Thermodynamics and Process Engineering, Technical University of Berlin, Ernst-Reuter-Platz 1,

10587 Berlin, Germany

E-mail: vrabec@tu-berlin.de

Abstract

The density of the quaternary mixture water+ methanol+ethanol +propan-2-ol as well as

its four ternary and six binary subsystems is measured over a wide composition range at ambi-

ent temperature and pressure, i.e. 298.15 K and 0.1 MPa. The resulting molar volume data are

correlated with a response surface model, consisting of linear, quadratic, bilinear and trilinear

interaction terms. The density values obtained with that correlation are compared to molecular

simulation results and experimental literature data. Further, the excess molar volume and the

partial molar volumes are determined for the ternary and quaternary mixtures. The analytical

solution for the partial molar volumes of a quaternary mixture for the response surface model

is also given.

Keywords: density, partial molar volume, water, alcohol

Introduction

The understanding of thermodynamic volumetric properties, such as density, excess and partial

molar volumes, is of importance to understand and describe solvation and mixing effects of liquid

mixtures. Several engineering design and optimization problems in the chemical industry require

quantitative information on the density of multicomponent liquid mixtures. For example, partial

molar volumes are required to convert Fick diffusion coefficients between different velocity ref-

erence frames. Solutions of water with alcohols in binary, ternary and quaternary systems are

expected to show a complex behavior due to the presence of strong intermolecular interactions

and self-association by hydrogen bonding. Thus, their study is of interest for the development and

evaluation of thermodynamic models for the description of the mixing behavior of polar solutions.

Further, mixtures containing alcohols are an important field of investigation due to their use as

sustainable energy carriers1,2.

This work is part of a systematic research on transport and volumetric properties of aqueous

mixtures with short alcohols based on experiments and molecular simulations3–6. Here, the den-

sity, excess and partial molar volumes of the quaternary mixture water+methanol+ ethanol +prop-

an-2-ol and all of its four ternary subsystems are presented. The six binary subsystems have been

thoroughly studied in the literature, e.g. in Refs.7–16, therefore only selected compositions of these

were measured for validation purposes.

Experimental measurements of the volumetric properties of the quaternary mixture under con-

sideration have been reported in the literature17, however, only 34 different compositions were

measured and no attempt was made to correlate these data. Further, molecular simulation re-

sults for the density of ten compositions of the quaternary mixture were reported in previous

work6. The volumetric properties of the ternary subsystem water+ methanol +ethanol has been

studied thoroughly in the literature10,11,18–20 and Zarei et al.10 as well as Mori et al.11 proposed

Redlich-Kister- and NRTL-type correlations for its excess volume. Wei and Rowley7studied the

density and kinematic viscosity of the ternary mixture methanol+ ethanol +propan-2-ol, but only

correlated the latter. The density of the ternary mixtures water+methanol + propan-2-ol and wa-

ter+ ethanol +propan-2-ol at 298.15 K and 0.1 MPa has been reported by Chen and Hou17, but the

data were not correlated.

Experimental

Materials

The purity of the employed anhydrous methanol, ethanol and propan-2-ol is given in Table 1.

Water deionized by reverse osmosis was used to prepare the mixture samples. The alcohols were

dried by chemical sieves before each set of measurements.

Table 1: Chemical formula, CAS registry number and mass fraction purity of the employed

chemicals.

Substance Formula CAS Reg. No. suppliers purity method

mass fraction

methanol CH4O 67-56-1 VWR chemicals ≥0.999 GCa

ethanol C2H6O 64-17-5 VWR chemicals ≥0.998 GCa

propan-2-ol C3H8O 67-63-0 Seccosolv R

Millipore ≥0.999 GCa

water H2O 7732-18-5 TU Berlin

aGas chromatography

Experimental method

The density ρwas measured at 298.15 K and 0.1 MPa for all six binary and four ternary subsystems

as well as the quaternary mixture itself with an Anton Paar DMA 5000 M vibrating-tube densimeter

with a precision of 0.001 kg·m−3and a reproducibility of 0.005 kg·m−3. The temperature was

controlled internally by two integrated platinum thermometers with a precision of 0.001 K. Sample

mixtures of about 5 cm3were prepared by weight using an analytical balance (Kern ABJ 220) with

a sensitivity of 0.1 mg. Before use, all pure substances were degassed by stirring under reduced

pressure. The densimeter was calibrated with water and air at 293.15K following the procedure

given by the manufacturer.

Initially, the density of the pure components was successfully compared with data from the

literature, cf. Table 2. An average absolute relative deviation (AARD) of 0.013% was found for

all substances. Subsequently, the density of the six binary subsystems at selected compositions

was measured and compared with correlations of experimental literature data7–16. Again, a very

good agreement between the present binary data and the literature was found with an AARD of

0.07% for the aqueous mixtures and of 0.03% for the alcoholic mixtures. A graphical comparison

is provided in Fig. S1 of the supporting information. Further, the calculated excess molar volume

was compared with other experimental literature data. A very good agreement was found for the

aqueous alcoholic mixtures, cf. Fig. 1. In the case of the binary mixtures containing two alcohols,

literature values exhibit strong scattering of the excess molar volume, which can be explained by

the extremely low values. Density and excess molar volumes of the binary mixtures are listed

in Table 3. The density of the ternary and quaternary mixtures was measured subsequently. The

density values of the ternary mixtures compare well with literature data, cf. Fig. S3 to S6 of the

supporting information. To cover the entire composition range of the quaternary mixture, the mass

fraction of the four components were varied sequentially in steps of 0.1 g/g. Further, the state

points studied in previous simulation work6were also measured. The alcohol/water mass ratio

varied between 0.053 and 2.33 and a total of 94 quaternary and 48 ternary composition points

were measured.

Uncertainties

The combined uncertainties of the density measurements were obtained with the error propaga-

tion law by considering the individual uncertainties from the employed densimeter and possible

temperature and pressure drifts. These uncertainties were estimated based on the temperature and

pressure dependence of the density of the pure components21–23. The expanded uncertainty of the

density was estimated to be U(ρ) = 0.014 kg·m−3. The combined uncertainty of the mole frac-

tions, excess and partial molar volumes was calculated with the error propagation law. In case of

the partial molar volumes, the largest part of the uncertainty originates from the fit, while the un-

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