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Liquid–liquid equilibrium (LLE) data of the ternary system 2-methyl-2-butanol + water + o-xylene were determined at 303.2, 313.2, and 323.2 K under 101.3 kPa. The extraction capacity of o-xylene is...

Liquid–liquid equilibrium (LLE) data for the ternary system sec-butyl alcohol + sec-butyl acetate + ethylene glycol were determined at 298.2, 308.2, and 318.2 K under 101.3 kPa. The extraction capa...

Liquid-liquid equilibrium (LLE) data for the ternary system of (2-methyl-2-butanol + water + n-octanol) were determined at 303.15 K, 313.15 K, and 323.15 K under atmospheric pressure. The Hand equation, the Othmer-Tobias equation, and the mass balance between the feed and the conjugated phases were used to test the reliability of the experimental LLE data. The results show that the correlation coefficients (R2) of the equations are close to 1, and the relative error of mass balance is less than 0.5%. The selectivity (S) was used to evaluate the capacity of n-octanol to extract 2-methyl-2-butanol from the water, which is much greater than 1. Furthermore, S decreases with the mass fraction of 2-methyl-2-butanol in the aqueous phase and increases with equilibrium temperature. The NRTL and UNIQUAC models were applied to correlate the experimental LLE data, and the binary interaction parameters were obtained. The root-mean square deviations (RMSDs) for the two models obtained are less than 1.1%.

Isobaric vapor–liquid equilibrium (VLE) for the binary system N , N -dimethyl formamide (DMF) + N , N -dimethyl acetamide (DMAC) and the quaternary system sec -butyl alcohol (SBA) + sec -butyl acetate (SBAC) + DMF + DMAC were determined at 101.3 kPa using a vapor–liquid equilibrium still. The thermodynamic consistency test for the experimental data was checked by Van Ness point test. The binary VLE data were correlated with the NRTL, UNIQUAC and Wilson activity coefficient models respectively. And the VLE data of the quaternary system predicted by the correlated binary interaction parameters agree well with the experimental data. And the mixture of DMF (3) and DMAC (4) can eliminate the pseudo-azeotrope of sec -butyl alcohol (1) + sec -butyl acetate (2). Thus, the mixture of DMF and DMAC is appropriate for separation of the pseudo-azotrope of SBA and SBAC by extractive distillation.

Isobaric vapour - liquid equilibrium (VLE) data for the binary systems of sec-butyl acetate (SBAC) + acetamide and sec-butyl alcohol (SBA) + acetamide and the ternary system of SBAC + SBA + acetamide were measured at 101.3 kPa using a modified Othmer still. The thermodynamic consistency tests for the experimental data were checked by Van Ness point test and Wisniak’s L-W method. The experimental VLE data of the binary systems were correlated with NRTL, Wilson and UNIQUAC activity coefficient models. The results indicate that the binary and ternary VLE data predicted by the three models agree well with the experimental data. And the ‘pseudo-azeotropic’ phenomenon of sec-butyl acetate + sec-butyl alcohol mixture can be eliminated by acetamide.

Isobaric vapor–liquid equilibrium (VLE) data for the quaternary system sec-butyl alcohol + sec-butyl acetate + N, N-dimethyl formamide (DMF) + dimethyl sulfoxide (DMSO) and the constituent binary system DMF + DMSO were determined at 101.3 kPa with a modified Othmer still. The measured experimental data of binary and quaternary systems were certified to be thermodynamically consistent according to the Van Ness method. And the experimental binary data were correlated by Wilson, NRTL and UNIQUAC activity coefficient models. The rest of binary interaction parameters have been obtained in our previous work. Then, the binary and quaternary vapor–liquid equilibrium were predicted by the models with the correlated parameters. The results show that the three models yield a good prediction for the binary and quaternary systems. But NRTL model performed better than the other two models in predicting VLE of the quaternary system.

Isobaric vapor–liquid equilibrium (VLE) data for the systems of methyl acetate + dimethyl sulfoxide (DMSO), methanol + DMSO and methyl acetate + methanol + DMSO were determined with a modified Othmer still at 101.3 kPa. And all experimental VLE data have passed the Herington and Van Ness thermodynamic consistency tests. The experimental binary VLE data were correlated by NRTL, Wilson and UNIQUAC models and the binary interaction parameters were obtained. And the VLE data predicted by the obtained parameters agree well with the experimental data. The binary azeotrope of methyl acetate and methanol is eliminated when the mole ratio of DMSO to the binary azeotrope is approximately 1.5:1. Therefore, DMSO is a promising extractive agent for the separation of the binary azeotrope of methanol and methyl acetate in extractive distillation.

Isobaric vapor–liquid equilibrium (VLE) data were measured for the binary systems sec-butyl alcohol + N,N-dimethyl acetamide (DMAC), sec-butyl acetate + DMAC and the ternary system sec-butyl alcohol + sec-butyl acetate + DMAC at 101.3 kPa using a vapor–liquid equilibrium still. The thermodynamic consistency test for the binary experimental data was made by Herington method and McDermott–Ellis method. And the thermodynamic consistency test for the ternary experimental data was made by McDermott–Ellis method. The binary VLE data were correlated with the NRTL, Wilson and UNIQUAC activity coefficient models. The obtained binary interaction parameters were used to predict the binary and ternary VLE data. The results indicate that the calculated values of vapor phase mole fraction and boiling temperature by the NRTL, Wilson and UNIQUAC models agree well with the experimental data. And the binary pseudo-azeotrope of sec-butyl alcohol and sec-butyl acetate was eliminated when the mass ratio of DMAC to the pseudo-azeotrope mixture is 6:5. Thus, DMAC is an appropriate solvent for separation of the mixture of sec-butyl alcohol and sec-butyl acetate in extractive distillation.

Isobaric vapor–liquid equilibrium (VLE) data were measured for the binary systems sec-butyl alcohol + dimethyl sulfoxide (DMSO), sec-butyl acetate + DMSO and the ternary system sec-butyl alcohol + sec-butyl acetate + DMSO at 101.3 kPa using a vapor–liquid equilibrium still. The thermodynamic consistency test for the binary experimental data was made by Herington method, Wisniak's L–W method and a point to point method of Van Ness test described by Fredenslund et al. And the thermodynamic consistency of the ternary system was checked by Van Ness test. The VLE data for the binary systems were correlated with the NRTL, Wilson and UNIQUAC activity coefficient models. And the binary and ternary VLE data predicted by the obtained binary interaction parameters agree well with the experimental data. The experimental results show that the relative volatility between sec-butyl alcohol and sec-butyl acetate is changed obviously when the mass ratio of DMSO to the pseudo-azeotrope mixture is 6:5. And DMSO is a promising extractive agent for the separation of the mixture of sec-butyl alcohol and sec-butyl acetate in extractive distillation.

The solubility and liquid–liquid equilibrium (LLE) data were measured for the ternary system methanol + acrylonitrile + water at 288.15 K, 298.15 K, and 313.15 K and atmospheric pressure. The quality of the experimental tie-line data has been checked by Hand and Othmer–Tobias correlations. The nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were applied to correlate the experimental data, and the interaction parameters for both models were regressed with an overall root-mean-square deviation (rmsd) less than 0.32 %. Selectivity values of water for methanol at the studied temperatures are within the range 1.5 < S < 26.5. The effect of temperature on the miscibility gap and the selectivity of water for methanol is minor.

Methylal is an important raw material and an excellent solvent in industry. The conventional methods for the synthesis of methylal have drawbacks such as corrosion to the equipments, catalyst isolation, high molar ratio of methanol to formaldehyde and high cost of equipments. To overcome these drawbacks, the synthesis of methylal was investigated in a pilot scale catalytic distillation column using Sulzer BX and the structured catalytic packing Katapak-SP 12 in the present study. The reaction was catalyzed by polystyrene based macroporous cation exchange resin (D72) which was filled in the catalystic layers of the structured packings. The effects of operating parameters such as reflux ratio, total feed rate, molar ratio of methanol to formaldehyde, catalyst weight, aqueous formaldehyde concentration were studied experimentally. The appropriate operating parameters obtained in the present study include: reflux ratio is 5; total feed rate is 3.10 kg/h; molar ratio of methanol to formaldehyde is 2.5, catalyst weight is 0.51 kg, aqueous formaldehyde concentration is 35.3%. Under the above operating conditions the average conversion of formaldehyde is 99.6% while the average methylal purity is 92.1%. In order to achieve higher purity of methylal at the top of the column, two different configurations: feeding aqueous formaldehyde and feeding water at mid-way of rectifying section, was tried in the experiments. The experimental results show that the former configuration surpasses the latter, under which the average conversion of formaldehyde is 99.8% and the average methylal purity is 99.1%.

Isobaric vapor−liquid equilibrium (VLE) data were measured for the binary systems ethyl methyl carbonate (EMC) + methanol, + ethanol, + dimethyl carbonate (DMC), and + diethyl carbonate (DEC) at 101.3 kPa using a vapor−liquid equilibrium still. The thermodynamic consistency of the experimental data was verified by Herington(1) method. The experimental VLE data were correlated with the Wilson, NRTL, and UNIQUAC activity coefficient models. The results show that the calculated values of vapor phase mole fraction and boiling temperature by the Wilson, NRTL, and UNIQUAC models agree well with the experimental data. Futhermore, azeotropic behavior was observed for the binary system of ethanol + EMC.

Batch distillation is widely used in chemical industries, but the role of initial still charge on batch distillation has not been well understood and is still the focus of debate among researchers....

The new mode of operation for slop cut withdrawal in batch distillation, i.e., draining column liquid holdup at the end of slop cut period, was proposed. And the stopping criterion for the operation was investigated. Experiments were carried out with isopropanol-n-propanol binary system and isopropanol-n-propanol-n-butanol ternary system in a distillation column with a liquid collector installed between the reboiler and the column section. Experimental results in a ф45mm batch column show that the proposed policy can overcome the flywheel effect caused by column liquid holdup and thus cut down operation time and energy consumption 31%-61%.