Experimental isobaric (vapor + liquid) equilibrium data for the binary system N, N-dimethyl formamide + dimethyl sulfoxide and the quaternary system sec-butyl alcohol + sec-butyl acetate + N, N-dimethyl formamide + dimethyl sulfoxide at 101.3 kPa
Introduction
sec-Butyl alcohol is widely used in industry, such as pharmaceutical intermediates, spices, dyes, flotation agents, polymerization additives, rubber additives, the solubilizers of nitrocellulose lacquer and nitrocellulose lacquer thinner and so on. But by now, it is mainly used to produce methyl ethyl ketone [1], [2]. The traditional methods of producing sec-butyl alcohol are indirect and direct hydration of butylene. The method of indirect hydration of butylene has two serious drawbacks: first, serious corrosion to equipment because of sulfuric acid as catalyst; second, low selectivity. Although the process of direct hydration of butylenes has overcome the drawback of corrosion, it requires high purity of raw material and has low conversion ratio [3], [4]. Recently, a novel method of producing sec-butyl alcohol by transesterifying sec- butyl acetate with alcohols was exploited by some researchers, which is superior to traditional method by the hydration of butylenes. In this new process, sec-butyl alcohol and sec-butyl acetate form a “pseudo-azeotrope”, in which the vapor and liquid composition is so close that it should be ignored nearly [5]. Extractive distillation as a special distillation is suitable to separate this type of systems. And Extractive agent selection is important aspect for a process of extractive distillation.
In our previous work, DMF (3) and DMSO (4) were certified to be effective extractive solvents for separation of sec-butyl alcohol (1) and sec-butyl acetate (2) and DMSO performed better than DMF [5], [6]. But the boiling point of DMSO is so high that it is likely to decompose when recovering extractive agent by distillation at 1 atm and even can cause explosion. If DMSO and DMF are mixed as extractive agent, the temperature of tower bottom can be reduced. At same time, DMF can inhibit the dissociation of DMSO at high temperature [7]. Consequently, the mixed solvent as extractive agent to separate sec-Butyl alcohol (1) and sec-Butyl acetate (2) is better than a single agent such as DMF (3) or DMSO (4) in industrial applications. So, it is necessary to measure isobaric VLE data for the quaternary system sec-Butyl alcohol (1) + sec-Butyl acetate (2) + DMF (3) + DMSO (4) and the constituent binary systems. The binary interactive parameters of the five systems: sec-butyl alcohol (1) + sec- butyl acetate (2) [8], sec-butyl alcohol (1) + DMF (3) [5], sec-butyl alcohol (1) + DMSO (4) [6], sec-butyl acetate (2) + DMF (3) [5], sec-butyl acetate (2) + DMSO (4) [6] have been obtained in our previous work. Guo L. et al. measured vapor pressure of the binary system of DMF (3) + DMSO (4) at various temperature and concentrations by using a quasi-static ebulliometer method [7]. But there is no isobaric VLE data for DMF (3) + DMSO (4) system and sec-butyl alcohol (1) + sec-butyl acetate (2) + DMF (3) + DMSO (4) system in open literatures. Thus, the absent isobaric VLE data for the two systems were explored experimentally in this work to supply basic data for the separation of sec-butyl alcohol (1) + sec-butyl acetate (2) by extractive distillation using the mixed solvent of DMF (3) and DMSO (4) as extractive agent.
Section snippets
Chemicals
In this work, Analytical reagents (AR), sec-butyl alcohol, sec-butyl acetate and DMF and DMSO were used. The molecular formula, CASRN, source, grade and mass fraction are listed in Table 1. The physical properties of the pure components are listed in Table 2, which are used to calculate fugacity coefficients. Purity of all these chemicals were checked by a gas chromatography (GC) equipped with a flame ionization detector (FID) and no appreciable peak of impurity was detected. And the water
Experimental data
The experimental VLE data of the binary system of DMF (3) + DMSO (4) and the quaternary system of sec-butyl alcohol (1) + sec-butyl acetate (2) + DMF (3) + DMSO (4) were measured with a modified Othmer still mentioned above at 101.3 kPa. The experimental data are listed in Table 4, Table 5.
Vapor-liquid equilibrium model
For low pressure and considering vapor non-ideality, the flowing Equation (1) [19], [20] is valid to describe VLE,where γi is the activity coefficient of component i in liquid
Conclusion
The VLE data of binary system of DMF (3) + DMSO (4) and quaternary sec-butyl alcohol (1) + sec-butyl acetate (2) + DMF (3) + DMSO (4) were measured with a modified Othmer still. The experimental VLE data have passed the Van Ness thermodynamic consistency test. Then the binary VLE data were correlated with Wilson, NRTL and UNIQUAC models and obtained their binary interaction parameters. And the VLE data for the binary and quaternary systems were predicted by the three models with these binary
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Experimental isobaric vapour-liquid equilibrium data for binary systems of {sec-butyl acetate (SBAC) + acetamide} and {sec-butyl alcohol (SBA) + acetamide} and the ternary system of (SBAC + SBA + acetamide) at 101.3 kPa
2020, Journal of Chemical ThermodynamicsCitation Excerpt :And the NRTL model performs better than Wilson and UNIQUAC model. To observe the effect of the extractive agent acetamide on the VLE behavior of the binary system SBAC (1) + SBA (2), the VLE data (y′ vs x′) and the mole fraction difference of SBA between vapour and liquid phase ((y′ − x′) vs. x′) for the binary system in the literature [12,22–27] and those in the measured ternary system excluding acetamide are shown in in Figs. 6 and 7, respectively. The figures show that the vapour compositions are almost identical with liquid ones when mole fraction of SBA is greater than 0.95 under no extractive agents.
Experimental isobaric vapour-liquid equilibrium data for the binary system (N, N-dimethyl acetamide + dimethyl sulfoxide) and the quaternary system (sec-butyl acetate + sec-butyl alcohol + N, N-dimethyl acetamide + dimethyl sulfoxide) at 101.3 kPa
2019, Journal of Chemical ThermodynamicsCitation Excerpt :SBA is mainly used in the production of methyl ethyl ketone (MEK) [1,2]. It is also used in pesticides, polymerization additives, gasoline additives and so on [3]. SBAC is an environmental friendly solvent used in metal cleaning agents, printing ink and spices [4,5].
Study of the Selectivity of Binary Agents by Gas–Liquid Chromatography
2020, Theoretical Foundations of Chemical Engineering