Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX-XXX
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Vapor−Liquid Equilibrium Data for Binary Mixtures of Dimethyl Carbonate with Methyl Acetate, Ethyl Acetate, n‑Propyl Acetate, Isopropyl Acetate, n‑Butyl Acetate, and Isoamyl Acetate at 93.13 kPa Nilesh A. Mali,*,† Satyajeet S. Yadav,‡ Pravin D. Ghuge,† and Sunil. S. Joshi† †
Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Pune, Maharashtra 411008, India Chemical Engineering Department, College of Engineering, Bharati Vidyapeeth Deemed University, Pune, Maharashtra 411030, India
‡
S Supporting Information *
ABSTRACT: Isobaric vapor−liquid equilibrium (VLE) data was measured at the local atmospheric pressure of 93.13 kPa for the binary systems of dimethyl carbonate (DMC) with methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and isoamyl acetate using a dynamic recirculation still. VLE data was generated in the form of T−x,y and was checked for thermodynamic consistency using the Herington area test, Van Ness test, and mean absolute deviation between experimental and calculated total pressure and vapor phase composition. Data for all pairs meet the criteria for thermodynamic consistency and were found suitable for process modeling. Binary interaction parameters for the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models were determined using the objective function of minimizing the deviation between the experimental and the calculated vapor phase composition and total pressure. For all binary systems, Wilson, NRTL, and UNIQUAC models gave good predictions. Azeotropic behavior was observed for the isopropyl acetate− DMC pair at 357.8 K and 0.6 mole fraction of isopropyl acetate.
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INTRODUCTION
EXPERIMENTAL SECTION Materials. Detail specifications of various chemicals used for experimentation are listed in Table 1. The chemicals were used
Dimethyl carbonate (DMC) finds a wide range of applications as a solvent in various chemical and pharmaceutical industries. The use of DMC as a gasoline additive or coadditive with primary alcohols such as ethanol or butanol has also been reported.1 Research on engine performance with DMC as gasoline additive have reported better performance along with reduction in smoke.2 Various esters also find numerous applications in process industries as a solvent, diluent, and flavor additive. Some esters are also used as a synthetic fruit flavoring agents in the food industry. As both, DMC and esters are used as solvent in process industries, VLE data are necessary for the modeling of processes in which a combination of these solvents exists. So far no experimental VLE data are available in the open literature for the binary systems of DMC with methyl acetate, ethyl acetate, n-propyl acetate, and isopropyl acetate except for DMC with n-butyl acetate and isoamyl acetate for which VLE data are available in the literature at 101.325 kPa.3,4 In the present work, the vapor−liquid equilibrium data for the binary systems, DMC + methyl acetate, DMC + ethyl acetate, DMC + n-propyl acetate, DMC + isopropyl acetate, DMC + n-butyl acetate, and DMC + isoamyl acetate have been determined at local atmospheric pressures of 93.13 kPa with a dynamic recirculation still. Binary interaction parameters estimated for various activity coefficient models will be useful for process simulation involving these components. © XXXX American Chemical Society
Table 1. Components, Supplier, and Purity of Chemicals chemical name
CAS
dimethyl carbonate methyl acetate ethyl acetate n-propyl acetate isopropyl acetate n-butyl acetate isoamyl acetate
616-38-6 79-20-9 141-78-6 109-60-4 108-21-4 123-86-4 123-92-2
source Loba Loba Loba Loba Loba Loba Loba
chemie chemie chemie chemie chemie chemie chemie
purity (mass %) 99 99 99.5 98 99 99.5 98
directly without any further purification. Table 2 contains the reported and experimental refractive index (nD) and boiling point (Tb) of the various chemicals used. Apparatus and Procedure. The present work uses a dynamic recirculation type glass VLE apparatus proposed by Mali et al.15 The apparatus comprises a boiling chamber, a Cottrell tube with vacuum jacket, an equilibrium chamber with vacuum jacket, a condenser, a condensate receiver, and an equilibrium liquid−vapor condensate mixer. A vacuum jacket Received: August 1, 2017 Accepted: November 7, 2017
A
DOI: 10.1021/acs.jced.7b00704 J. Chem. Eng. Data XXXX, XXX, XXX−XXX
Journal of Chemical & Engineering Data
Article
tion range. The refractive index was measured by a refractometer from Atago (model-RX-7000i) with an accuracy of ±0.0001 and resolution of 0.00001. It has a refractive index measurement range of 1.32422 to 1.70000 with Peltier-based temperature control. Equations for the calibration curve were obtained by fitting a suitable polynomial equation using Microsoft Excel software. The composition of the equilibrium samples were estimated by measuring the refractive index and solving the calibration equation.
Table 2. Refractive Index (nD) and Boiling Temperature (Tb) of Pure Components refractive index (nD) at 25 °C chemical dimethyl carbonate methyl acetate ethyl acetate n-propyl acetate isopropyl acetate n-butyl acetate isoamyl acetate
boiling point (K)
lit.
measureda
lit. (at 101.325 kPa)
measureda (at 93.13 kPa)
1.366541
1.36640
363.462
360.73
1.35955 1.35876 1.369787 1.38218 1.38169 1.37525 1.375010 1.3919412
1.35872
327.63
1.397713 1.3983614
1.39842
330.955 329.956 350.257 374.578 374.559 361.655 361.7510 399.1511 399.0012 415.1913
1.36980 1.38181 1.37480 1.39175
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RESULTS AND DISCUSSION Experimental Data for Calibration Curves. The calibration curves for composition measurement were generated by measuring nD at 293.15 K for various different compositions of binary mixtures covering complete composition range and are given in the Supporting Information document. The samples were prepared using an electronic weighing balance with an uncertainty of ±0.1 mg. A suitable polynomial equation was fitted to the experimental nD vs mole fraction data using Microsoft Excel to obtain polynomial constants of the equation. The polynomial equations used for composition measurement are given in Table 3.
347.58 372.05 358.92 396.21 412.31
a
Standard uncertainties u are u(nD) = 0.0001, u(T) = 0.1 K, u(P)=0.1 kPa.
was provided to the Cottrell tube and the equilibrium chamber to avoid heat losses. A binary liquid mixture was initially fed to the boiling chamber which was provided with an external electrical heater. A suitable heating rate was set for the heater with the help of a rheostat attached to the heater. The vapor− liquid mixture rises up to the equilibrium chamber through the insulated Cottrell tube. The equilibrium chamber was packed with glass ball packing to enhance vapor−liquid contact area. Vapor−liquid comes in equilibrium with each other because of sufficient contact time and contact area provided jointly through the Cottrell tube and the equilibrium chamber. Temperature measurement was provided in the equilibrium chamber to sense the vapor−liquid equilibrium temperature. In the equilibrium chamber, vapor and liquid separates and vapor heads toward the condenser and get condensed with a suitable cooling medium circulated through the condenser. The vapor condensate collects in a receiver and overflows to the mixing chamber where it mixes with the liquid from the equilibrium chamber. Both, the vapor condensate receiver and the mixing chamber, were provided with magnetic stirrers to avoid any concentration gradient. The mixed liquid flows back to the boiling chamber to complete the circulation loop. Sufficient time was given for the vapor−liquid circulation so that equilibrium was achieved which was indicated by a constant temperature in the equilibrium chamber. Once a constant temperature was achieved, samples were collected for equilibrium liquid from the equilibrium chamber and equilibrium vapor from the condensate receiver. When the composition of the consecutive samples collected was constant, attainment of vapor−liquid equilibrium was confirmed and the experiment was stopped. While samples were being withdrawn, very small quantities (
