Bubble points measurement for (triethyl orthoformate + diethyl malonate)
Introduction
Triethyl orthoformate (TEOF, CAS RN 122-51-0) and diethyl malonate (DEM, CAS RN 105-53-3) are important intermediates and raw materials for the organic syntheses [1]. During the process of ethoxy methylene diethyl malonate production, the important intermediate of norfloxacin and dyestuff, such information is needed for the separation of TEOF and DEM. The binary isothermal (vapour + liquid) equilibria data of TEOF with alkanes and alkenes, and the isobaric (vapour + liquid) equilibria of the ternary system (TEOF + ethanol + benzene) are available in the literature [1], [2]. Unfortunately, the VLE data for (TEOF + DEM) system are not reported in the literature. To further understand the nature of TEOF and to design the more efficient separation processes, the isothermal and isobaric VLE data are indispensable.
In this paper, the isothermal and isobaric VLE for (TEOF + DEM) at T = (373.15, 383.15, and 393.15) K, and at the pressures ρ = 13.33 kPa are reported. The binary VLE data are correlated using the UNIQUAC equation with the temperature-dependent binary parameters. Experimental vapour pressures of TEOF are included.
Section snippets
Experimental
TEOF and DEM (highest commercial grade, Zhejiang NHU Co., Ltd.), were distilled by using a 150 cm high column packed with vitreous springs. The purity of the materials was checked in our laboratory by gas chromatography, and the values obtained were >0.998 mass fraction (g.c.) for all the compounds. The physical properties of the pure materials are listed in table 1 along with the literature values [1], [3]. Densities of the pure materials and mixtures were measured with an Anton Paar DMA 602
Results and discussion
The measured binary bubble points and calculated VLE data are listed in TABLE 3, TABLE 4. The data were correlated using the UNIQUAC equation with the temperature-dependent binary parameters.
At (vapour + liquid) equilibriumwhere p is the total pressure, yi is the vapour mole fraction of component i, and ϕi is the fugacity coefficient of component i, calculated from virial equationwhere the second virial coefficient of pure substances Bii
Acknowledgements
This work was financed by the National Postdoctoral Science Foundation of China (No. 2003033536) and Zhejiang Province Natural Science Foundation of China (No. RC01051).
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