LLE data for the ionic liquid 3-methyl-N-butyl pyridinium dicyanamide with several aromatic and aliphatic hydrocarbons

(Liquid + liquid) equilibrium data for ternary systems of several aromatic and aliphatic hydrocarbons with the ionic liquid 3-methyl-N-butylpyridinium dicyanamide were determined at T = 303.15 K and 328.15 K and atmospheric pressure. As aromatics benzene, cumene and p-xylene have been chosen, as paraffins n-hexane and n-nonane were used. The experimental data were regressed and could be adequately correlated with the NRTL model. A logical order in the extraction capacity of 3-methyl-N-butylpyridinium dicyanamide for the different aromatics is obtained: benzene > p-xylene > cumene

Ionic liquid screening for ethylbenzene/styrene separation by extractive distillation

The separation of ethylbenzene from styrene by distillation is very energy-intensive, because of the low relative volatility (1.3–1.4). Extractive distillation is a promising alternative to separate the close boiling mixture, in which the solvent selection is crucial for the process feasibility. In this work, an ionic liquid screening study by liquid–liquid equilibrium (LLE) experiments has been performed to investigate whether ionic liquids (ILs) show potential to separate ethylbenzene from styrene by extractive distillation. The screening method by LLE experiments was validated by VLE experiments for several ILs. The performance of the ILs was compared with the benchmark solvent sulfolane, which displays a selectivity of 1.6. Several ILs outperform sulfolane with selectivities up to 2.6. From the results of the LLE experiments, it was concluded that there is a clear tradeoff between capacity and selectivity. ILs with a high capacity usually have a low selectivity, whereas ILs with high selectivity exhibit low capacity. Both cation and anion structure strongly influence the performance. The highest selectivities (2.4–2.6) were obtained with ILs containing aromatic cations, and anions with localized electrons. The largest capacities (0.45–0.6 for styrene) were obtained for ionic liquids with delocalized electrons in the anion and large alkyl chain length in both cation and anion

Binary and ternary LLE data of the system (ethylbenzene + styrene + 1-ethyl-3-methylimidazolium thiocyanate) and binary VLE data of the system (styrene + 1-ethyl-3-methylimidazolium thiocyanate)

The distillation of close boiling mixtures may be improved by adding a proper affinity solvent, and thereby creating an extractive distillation process. An example of a close boiling mixture that may be separated by extractive distillation is the mixture ethylbenzene/styrene. The ionic liquid 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) is a promising solvent to separate ethylbenzene and styrene by extractive distillation. In this study, (vapour + liquid) equilibrium data have been measured for the binary system (styrene + [EMIM][SCN]) over the pressure range of (3 to 20) kPa and binary and ternary (liquid + liquid) equilibrium data of the system (ethylbenzene + styrene + [EMIM][SCN]) at temperatures (313.2, 333.2 and 353.2) K. Due to the low solubility of ethylbenzene in [EMIM][SCN], it was not possible to measure accurately VLE data of the binary system (ethylbenzene + [EMIM][SCN]) and of the ternary system (ethylbenzene + styrene + [EMIM][SCN]) using the ebulliometer. Because previous work showed that the LLE selectivity is a good measure for the selectivity in VLE, we determined the selectivity with LLE. The selectivity of [EMIM][SCN] to styrene in LLE measurements ranges from 2.1 at high styrene raffinate purity to 2.6 at high ethylbenzene raffinate purity. The NRTL model can properly describe the experimental results. The rRMSD in temperature, pressure and mole fraction for the binary VLE data are respectively (0.1, 0.12 and 0.13)%. The rRMSD is only 0.7% in mole fraction for the LLE data.\ud \u

Ionic liquid screening for ethylbenzene/styrene separation by extractive distillation

The separation of ethylbenzene from styrene by distillation is very energy-intensive, because of the low relative volatility (1.3–1.4). Extractive distillation is a promising alternative to separate the close boiling mixture, in which the solvent selection is crucial for the process feasibility. In this work, an ionic liquid screening study by liquid–liquid equilibrium (LLE) experiments has been performed to investigate whether ionic liquids (ILs) show potential to separate ethylbenzene from styrene by extractive distillation. The screening method by LLE experiments was validated by VLE experiments for several ILs. The performance of the ILs was compared with the benchmark solvent sulfolane, which displays a selectivity of 1.6. Several ILs outperform sulfolane with selectivities up to 2.6. From the results of the LLE experiments, it was concluded that there is a clear tradeoff between capacity and selectivity. ILs with a high capacity usually have a low selectivity, whereas ILs with high selectivity exhibit low capacity. Both cation and anion structure strongly influence the performance. The highest selectivities (2.4–2.6) were obtained with ILs containing aromatic cations, and anions with localized electrons. The largest capacities (0.45–0.6 for styrene) were obtained for ionic liquids with delocalized electrons in the anion and large alkyl chain length in both cation and anion

Binary and ternary vapor-liquid equilibrium data of the system (Ethylbenzene plus Styrene+4-Methyl-N-butylpyridinium Tetrafluoroborate) at vacuum conditions and liquid-liquid equilibrium data of their binary systems

Ethylbenzene and styrene are currently separated by ordinary fractional distillation, which is challenging due the low relative volatility of this mixture of 1.3 to 1.4. Extractive distillation is a promising alternative to save capital and operational expenditures. Recently, ionic liquids (ILs) have been reported as a promising option to replace commonly used organic solvents like sulfolane. The IL 4-methyl-N-butylpyridinium tetrafluoroborate ([4-mebupy] [BF4]) is an IL with a strong effect on the relative volatility of the ethylbenzene/styrene mixture. In this work, binary VLE data in the range of (3 to 30) kPa, ternary VLE data at (5, 10, and 15) kPa, and binary LLE data at (313.2, 333.2, and 353.2) K have been determined for the system (ethylbenzene + styrene + [4-mebupy][BF4]). The ternary VLE experiments show that [4-mebupy][BF4] can enhance the relative volatility up to 2.7 to 2.8, and thereby [4-mebupy] [BF4] has a stronger effect on the relative volatility than the benchmark solvent sulfolane, which can increase the relative volatility up to 2.3. Therefore, [4-mebupy][BF4] is a promising solvent for use in extractive distillation to separate ethylbenzene from styrene. The binary and ternary VLE data were correlated separately with the NRTL model and were regressed both together with the binary LLE data. The NRTL model could describe both data sets properly. The ternary VLE data could not be properly calculated by the binary NRTL parameters determined solely from the binary system

Isobaric low pressure vapor-liquid equilibrium data for the binary system monochloroacetic acid + dichloroacetic acid

Isobaric vapor–liquid equilibrium (VLE) data for the binary system monochloroacetic acid + dichloroacetic acid have been measured at 5, 7.5, and 10 kPa. The VLE data measured in this work is thermodynamically consistent according to the Herington area method. The non-ideal behavior in the vapor phase was correlated using the Hayden–O’Connell model. Wilson, NRTL, and UNIQUAC were used to account for the liquid phase non-idealities. All activity coefficient models were able to describe the experimental VLE data very well. Wilson and UNIQUAC described the VLE data slightly better than NRTL. The correlated equilibrium temperatures and vapor phase compositions were in all cases in good agreement with the experimental data.\ud \ud \u

Isobaric low-pressure vapor-liquid equilibria for ethylbenzene+styrene+sulfolane and the three constituent binary systems

Isobaric vapor–liquid equilibrium (VLE) data have been measured for the ternary system (ethylbenzene + styrene + sulfolane) and the three constituent binary systems under vacuum [(5, 10, and 20) kPa]. The VLE data of the binary system (ethylbenzene + styrene) measured in this work are thermodynamically consistent according to the Herington area test and the point test method contrary to the low pressure VLE data about this system available in the literature. The binary VLE data were described well by the nonrandom two-liquid (NRTL) model. The relative volatility of the system (ethylbenzene + styrene) increases in the presence of sulfolane from 1.4 up to values of 2.2. The ternary system could only be well-correlated when using the ternary VLE data in combination with the binary VLE data as input for the regression of the NRTL binary interaction parameters

Extractive Distillation of Ethylbenzene and Styrene using Sulfolane as Solvent: Low Pressure Isobaric VLE Data

The distillation of ethylbenzene (EB) from styrene (SM) is very energy intensive. By using extractive distillation instead, both capital and energy expenses are potentially reduced dramatically. Hereto we propose to use sulfolane (SF) as solvent. Currently there is no ternary vapor liquid equilibrium (VLE) data available of the system SM/EB/SF and the binary VLE data sets of EB/SM available in literature are found to be thermodynamically inconsistent. In this study thermodynamically consistent VLE data is obtained for the three binary systems and the ternary system in the pressure range of 50-200 mbar. Both the Wilson and NRTL model can adequately describe the experimental VLE data. The solvent SF increases the relative volatility significantly from 1.3-1.4 up to 2.3. Equilibrium process modeling suggests that an energy reduction of 50% compared to the traditional distillation process can be obtained with the extractive distillation process