VLE of the binary systems (dimethyl carbonate with 2-propanol or 2-butanol) and (diethyl carbonate with methylcyclohexane) at 101.3 kPa

doi:10.1016/j.jct.2004.09.009

The Journal of Chemical Thermodynamics

Volume 37, Issue 3, March 2005, Pages 249-257

https://doi.org/10.1016/j.jct.2004.09.009 Get rights and content

Abstract

Isobaric vapour + liquid equilibria (VLE) have been experimentally determined for the binary systems (2-propanol + dimethyl carbonate (DMC), dimethyl carbonate + 2-butanol, and methylcyclohexane + diethyl carbonate (DEC)) at 101.3 kPa. The activity coefficients were calculated to be thermodynamically consistent and were correlated with the Wilson, NRTL, and UNIQUAC equations. ASOG and UNIFAC group contribution methods will be employed to predict these binary systems. Densities at T = (293.5, 298.15, 303.15, 308.15, and 313.15) K and atmospheric pressure have been measured over the whole composition range for (DEC + methylcyclohexane). Excess molar volumes have been calculated for each temperatures. A polynomial equation has been used to estimate the binary fitting parameters as a function of mole fraction and temperature. Standard deviations from the regression lines are shown for the binary mixture.

Introduction

This paper is a continuation of the thermodynamic study of esters of carbonic acid with alkanes and alcohols [1], [2], which is arousing an increasing interest due to dimethyl carbonate (DMC) is considered an option for meeting the oxygenated specifications on gasoline and as a means of converting natural gas to a liquid transportation fuel [3].

In this work, the densities of the binary mixture (diethyl carbonate (DEC) + methylcyclohexane) at T = (293. 15, 298.15, 303.15, 308.15, and 318.15) K and atmospheric pressure have been measured. The excess molar volumes have been calculated over the entire mole fraction range for this mixture.

A modified polynomial equation [4] has been used to correlate the excess quantities as a function of mole fraction and temperature. The standard deviations between experimental and calculated values are shown. No experimental data corresponding to density have been found in the literature on the binary mixtures.

Experimental data of isobaric vapor + liquid equilibria for the binary systems (2-propanol + DEC, DMC + 2-butanol, and methylcyclohexane + DEC) at 101.3 kPa have been determined. In this case, there have no been found data in the literature, either. The experimental results will be compared with those correlated through the equation of Wilson [5], NRTL [6], and UNIQUAC [7]. Predictive methods [8], [9], based on contribution groups, have been used to predict the experimental VLE data. The interaction parameters of the functional group (OCOO) with (CH₂), (ArCH) and with (OH) in ASOG method and (OCOO) with (CH₂) and with (CH₃OH) and (OH) in UNIFAC method have been determined [10], [11]; using previous experimental isobaric VLE data. Comparison between experimental and predictive VLE data have been made.

Section snippets

Experimental

The pure components were supplied by Merck except DMC by Fluka. They were degassed ultrasonically, and dried over molecular sieves type 0.3 and 0.4 nm (supplied by Aldrich) and kept in an inert argon atmosphere. Chromatographic testing of the reagents showed purities, which fulfilled purchaser specifications. Their mass fraction purities were more than 0.99 for DMC, 0.995 for diethyl carbonate, 0.999 for 2-propanol, 0.995 for 2-butanol, and more than 0.99 for methylcyclohexane. The maximum

Results and discussion

Density and excess molar volume for the binary mixture (DEC + methylcyclohexane) at T = (293.15, 298.15, 303.15, 308.15, and 318.15) K are reported in table 2. Excess molar quantities, for the binary mixtures, were derived, respectively, from: $V_{m}^{E} = \sum_{i = 1}^{N} x_{i} M_{i} (ρ^{- 1} - {ρ_{i}^{\circ}}^{- 1}) .$ In this equation, ρ is the density of the mixture and $ρ_{i}^{\circ}$ is the density of pure components. The binary excess properties were fitted to a polynomial equation: $V_{m}^{E} = x (1 - x) \sum_{i = 1}^{2} \sum_{j = 1}^{2} A_{ij} x^{i / 8} {(T - T_{0})}^{j - 1},$ where T₀ is 298.15 K, x is the mole

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VLE of the binary systems (dimethyl carbonate with 2-propanol or 2-butanol) and (diethyl carbonate with methylcyclohexane) at 101.3 kPa

Abstract

Introduction

Section snippets

Experimental

Results and discussion

J. Chem. Thermodyn.

Fluid Phase Equilib.

Fluid Phase Equilib.

Fluid Phase Equilib.

Fluid Phase Equilib.

Fluid Phase Equilib.

J. Chem. Eng. Data

Energy & Fuels

J. Chem. Thermodyn.

J. Am. Chem. Soc.

AIChE J.

AIChE J.

Prediction of vapor-liquid equilibria by the ASOG method

AIChE J.

J. Chem. Eng. Data