Isobaric vapor–liquid equilibrium for binary system of N, N-dimethyl formamide + N, N-dimethyl acetamide and quaternary system of sec-butyl alcohol + sec-butyl acetate + N, N-dimethyl formamide + N, N-dimethyl acetamide at 101.3 kPa
Introduction
sec-Butyl alcohol (SBA) is an important intermediate for production of methyl ethyl ketone. It is also used as pesticides mineral-dressing agent, emulsifiers, plasticizers and the co-solvent of methanol for improving the octane number of gasoline [1], [2], [3]. SBA is traditionally produced by hydration of n-butene with water. The indirect hydration process uses sulfuric acid as catalyst and causes serious equipment corrosion and low selectivity [4], [5]. Direct hydration process avoids the drawback of corrosion to equipment by replacing sulfuric acid with acidic catalyst, such as heteropolyacid, resin and molecular sieve. But it requires high reaction temperature and pressure, more energy consumption and high purity of n-butene and has low conversion of n-butene [5], [6]. To develop an efficient, stable, environment-friendly process for SBA, the transesterification of sec-butyl acetate (SBAC) with alcohols was presented by researchers [7], which has high conversion, low energy-consumption and no corrosion to equipment.
In the process of transesterification of SBAC with alcohols, SBA and SBAC can form a pseudo-azotrope [8]. Extractive distillation is effective in separation of close-boiling, azeotropic and pseudo-azeotropic systems, in which solvent selection is essential. Berg indicted that the mixture of N, N-dimethyl formamide (DMF) and N, N-dimethyl acetamide (DMAC) is effective in separation SBA from SBAC [9]. However, the VLE data of DMF (3) + DMAC (4) and SBA (1) + SBAC (2) + DMF (3) + DMAC (4) have not been found in the opened literature so far. The VLE data is very important for the simulation and design of the extractive distillation column [10]. Thus, isobaric VLE data at 101.3 kPa of the two systems were measured in this work to provide fundamental data for the separation of SBA and SBAC by extractive distillation.
Section snippets
Chemicals
Analytical reagents (AR), SBA, SBAC, DMF and DMAC were used in this work, whose information is listed in Table 1. Purity of all these chemicals were checked by a gas chromatograph (GC) equipped with a flame ionization detector (FID), and no appreciable peak of impurity was detected. The water contents determined by Karl Fischer titration were less than 0.003 (mass fraction). Therefore, all of the chemicals were used without further purification.
Apparatus and procedure
The VLE data were determined in a circulation
Experimental data
In this work, the isobaric VLE data of the binary system DMF (3) + DMAC (4) and the quaternary system SBA (1) + SBAC (2) + DMF (3) + DMAC (4) were measured by the modified Othmer still at 101.3 kPa. The experimental data are listed in Table 2 and Table 3, respectively.
Vapor–liquid equilibrium model
The activity coefficient can be calculated by the following equation [13].where yi and xi are the mole fractions of component i in the vapor and liquid phases, respectively; P
Conclusions
The isobaric VLE data for the binary system DMF (3) + DMAC (4) and the quaternary system SBA + SBAC + DMF + DMAC at 101.3 kPa was measured in a circulation vapor–liquid equilibrium still. The binary VLE experimental data were checked with the Herington area method and the Van Ness test and confirmed to be thermodynamic consistent. The NRTL, UNIQUAC and Wilson models were used to correlate the VLE data of the binary system DMF (3) + DMAC (4). And the VLE behaviors of the quaternary system SBA
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Densities and excess volumes of binary and ternary mixtures of N, N-dimethyl sulfoxide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone at T = (293.15, 313.15)K and atmospheric pressure
2022, Chemical Data CollectionsCitation Excerpt :DMA is considered as potential extractive agent, since it selectively increases the relative volatility of the substances [15–17]. The use of mixed extractive agents containing one of discussed solvents can provide a number of advantages [18–25]. The purpose of using mixed extractive agents is to selectively influence molecular interactions in the separated mixtures.
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 :Vapour-liquid equilibrium (VLE) data are fundamental in simulation and design of the extractive distillation column. Our previous work has presented the VLE data in separating SBAC and SBA by extractive distillation using N, N-dimethyl acetamide (DMAC) [22], N, N-dimethyl formamide (DMF) [23], dimethyl sulfoxide (DMSO) [24] and their binary mixture as extractive agents [25–27]. Up to now, the VLE data of the system SBAC + SBA + acetamide have not been found in the literature.
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 :The vapour-liquid equilibrium (VLE) data are indispensable for the simulation and design of the extractive distillation column. Our previous work has investigated the VLE of using N, N-dimethyl acetamide (DMAC) [4], N, N-dimethyl formamide (DMF) [21], dimethyl sulfoxide (DMSO) [22] and the mixture of DMAC and DMF [23] as extractive solvents in separation of SBAC and SBA. However, the VLE data of the system of (SBAC + SBA + DMAC + DMSO) have not been found in the literature.