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Article

High-Pressure Phase Equilibrium Studies of Multicomponent (Alcohol-Water-Ionic Liquid-CO2) Systems

by
Małgorzata E. Zakrzewska
1,2,*,
Ana B. Paninho
2,
M. Fátima C. Guedes da Silva
1 and
Ana V. M. Nunes
2
1
Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
2
LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
*
Author to whom correspondence should be addressed.
C 2020, 6(1), 9; https://doi.org/10.3390/c6010009
Submission received: 31 January 2020 / Revised: 19 February 2020 / Accepted: 22 February 2020 / Published: 25 February 2020
(This article belongs to the Special Issue Ionic liquids for CO2 Capture and Reduction)
Browse Figures
Versions Notes

Abstract

:
Selective water (by-product) separation from reaction mixtures stands as an important process intensification strategy for equilibrium-limited reactions. In this work, the possibility of using a high-pressure biphasic reaction media composed of a hydrophobic ionic liquid, 1-hexy-3-methylimidazolium tetracyanoborate, and carbon dioxide was explored for levulinic acid production from 1,4-butanediol. Vapour-liquid equilibrium measurements were performed for the binary (diol+CO2), ternary (diol+CO2+IL), and quaternary systems (diol+CO2+IL+water), at 313.2 K and pressures up to 18 MPa. The static analytical method was used in a high-pressure phase equilibrium apparatus equipped with a visual sapphire cell. The capability of the quaternary system to perform physical water separation is discussed in this paper.

Graphical Abstract

1. Introduction

Production of chemicals from renewable sources, such as commodity sugars, lignocellulosic biomass, or algae, is a promising strategy to reduce the worldwide dependence on fossil-derived feedstocks. At the end of 2016, Novamont announced the opening of the world’s first industrial plant dedicated to the production of 1,4-butanediol (1,4-BDO) directly from sugars and through the use of bacteria [1]. Applying the technology developed by Genomatica, based on the action of suitably engineered Escherichia coli strain [2,3], the biorefinery was designed to produce 30,000 tons per year of the low-impact bio-alcohol. Already, eight months after the grand opening, the company confirmed that the new plant has met all performance guarantees and runs as planned. 1,4-butanediol is a chemical intermediate which finds wide-scale industrial applications in the production of, e.g., elastic fibers, plastics, or solvents. Its key end-products are tetrahydrofuran (THF), polybutylene terephthalate (PBT), gamma-butyrolactone (GBL), and polyurethanes (PU), among others [4,5]. Until 2016 1,4-BDO was manufactured entirely from petroleum-based feedstocks such as acetylene, butane, propylene, and butadiene. The demand for 1,4-BDO in 2019 was roughly 4.3 million tons, resulting in a market worth approximately US$5.7 billion. Given the increasing importance of this compound, it is estimated this market will reach more than US$ 10.3 billion by 2025.
Climate change poses one of the most pressing challenges worldwide and is predominantly caused by an increasing release of greenhouse gases. Carbon dioxide, the most abundant waste gas, is predicted to become a cheap and readily available (in a compressed form) feedstock thanks to the future implementation of carbon capture, usage and storage (CCUS) technologies. A wide window of opportunities will open for the captured carbon dioxide to be utilized as a raw material in the production of a variety of industrial products and applications.
CCUS is a fast-developing field and many critical reviews on this subject have already been published [6,7,8,9,10,11]. Recently, Roh et al. not only reviewed the carbon dioxide conversion processes currently under investigation in the literature, but also described relevant gaps and opportunities in the field, giving examples of potential pathways and reaction networks [11]. Based on these ideas, Putra et al. proposed a new route for a production of ethyl levulinate, an alternative fuel additive, from waste carbon dioxide and 1,4-butanediol [12]. This method comprises the synthesis of levulinic acid (a very important platform chemical itself [13]) from the reaction between carbon dioxide and diol, and subsequent esterification of the acid thus obtained with ethanol (Figure 1).
The authors followed the technical evaluation of the process with an economic and sensitivity analysis and concluded that the process is always profitable provided the ethyl levulinate remains slightly more expensive than the 1,4-butanediol. Nevertheless, due to the lack of reaction data for the first step of levulinic acid formation, several assumptions must be considered. First, to be assured that the production process is commercially viable, it is imperative to find an efficient, eco-friendly, and cost-effective catalyst. Second, the reaction under consideration has a severe equilibrium limitation caused by the formation of high quantities of water, which should be removed from the reaction mixture. In their approach, Putra et al. envisaged a distillation operation [12]. In this work, in order to avoid this energy-intensive step, we investigate the possibility of performing the synthesis in a supercritical carbon dioxide-ionic liquid (CO2+IL) system. Most ionic liquids can absorb high concentrations of carbon dioxide, while they are not soluble in dense carbon dioxide to any measurable extent [14]. As a consequence, the (CO2+IL) binary systems are always biphasic with multiple options to adjust their solvent properties, e.g., changing pressure, temperature, or structure of ILs ions, which provides a versatile reaction and separation environment. Coupling ionic liquids with carbon dioxide further decreases the viscosity of the liquid phase, improving diffusivity and mass transfer of compounds [15,16], an important factor in the case of the highly viscous 1,4-butanediol [17]. In our approach we explore the hydrophobic nature of a particular ionic liquid, 1-hexyl-3-methylimidazolium tetracyanoborate [18,19], and investigate its feasibility to remove water from the liquid reaction mixture into the dense carbon dioxide phase, shifting the reaction equilibrium towards the product formation. This study is part of an on-going project in our laboratory and comprises the measurement of vapour-liquid equilibria of multicomponent systems under high carbon dioxide pressures, up to 18MPa, and temperature of 313.2 K.

2. Materials and Methods

2.1. Materials

Ionic liquid used in this work, 1-hexyl-3-methylimidazolium tetracyanoborate ([hmim][B(CN)4]) (≥ 98.0% purity), was purchased from Merck KgaA, Darmstadt, Germany, and used without further purification (water content < 300 ppm). Carbon dioxide (99.98% purity) was supplied by Air Liquide and also used as received. 1,4-butanediol and 1-butanol (GC internal standard) were supplied by Sigma-Aldrich, Algés, Portugal, with purity of 99 and more than 99.7%, respectively. Absolute anhydrous ethanol of 99.9% purity (Carlo Erba, Barcelona, Spain) was used only as a solvent in vapour-liquid equilibrium measurements to wash the lines, and in gas chromatography analysis. All alcohols were dried over molecular sieves with 0.3 nm pore diameter (Fluka), for at least 24h, prior to their use. Distilled water (Diwer Technologies Water max station Type I) was used to prepare particular samples of ternary or quaternary systems.

2.2. Apparatus and Experimental Procedure

A detailed and up-to-date description of the facility and methodology used to measure vapour-liquid equilibrium can be found in the work of Rebocho et al. [20]. Here, only an overview is given. The essence of the apparatus is a high-pressure cylinder-shaped sapphire cell (15 cm of height and 3.2 cm/1.9 cm of external/internal diameter). It is placed inside a thermostatic air bath with a window allowing visualisation of the internal volume. A high-power ventilator ensures a uniform distribution of heat and temperature is measured by the Hart Scientific temperature controller (model 2100) coupled with an RTD probe from the same supplier (model 2622). The pressure in the system is gauged by the Setra pressure transducer (model Model 204/C204), with an accuracy of determination of ±0.007 MPa. The estimated temperature uncertainty is ±0.1 K.
A typical experiment started with the removal of all gases from the system by means of a vacuum pump (Edwards, model RV3). A certain amount of liquid sample, with a known composition, was then loaded into the cell and heated up to the required temperature. After temperature was attained, carbon dioxide was compressed and slowly added to the cell up to the desired pressure. In order to accelerate equilibration of liquid and vapour phases, the entire content of the cell was mixed with a magnetic stirrer. Based on the experience gained in previous measurements performed in our laboratory [20,21,22,23], two hours are enough to reach equilibrium conditions. Once this happens, samples from gas and vapour phases were withdrawn through two HPLC valves into previously evacuated sample loops, and subsequently expanded to a low-pressure calibrated volume. The amount of CO2 in each sample was calculated from the measurement of pressure after expansion. In order to ascertain the reproducibility of measurements all experiments were performed at least three times. The average standard deviation of the mole fraction of carbon dioxide is ±0.0002 for the vapour phase and ±0.031 for the liquid phase (the quaternary system).
Concentrations of water and alcohol were determined by Karl-Fischer coulometric titration method (Metrohm 831 Karl Fischer coulometer) and chromatography, respectively. The vapour phase samples were analysed in a gas chromatographer equipped with a flame ionization detector (GC-FID) and a ZB-1HT Inferno capillary column (15 m, 0.25 ID, 0.1 film). Helium gas served as the carrier gas and 1-butanol as the internal standard. Liquid phase samples were analysed by HPLC (DIONEX ICS3000) coupled with a refractive index detector, using silica-based Phenomenex Luna C8 column (250 mm × 4.6 mm, conditions: developing solvent: water/methanol = 70/30, 1 mL/min., 313.2 K). The quantity of the ionic liquid was calculated by volume difference between calibrated sampling loop and experimentally determined amounts of water, carbon dioxide, and diol. The average standard deviation of mole fractions of alcohol, water, and ionic liquid were up to ±0.009, ±0.004, and ±0.019, respectively, for the liquid phase, and ±0.00005 and ±0.0001 for the alcohol and water, respectively, in the gaseous phase.

3. Results and Discussion

In order to examine the feasibility of the ionic liquid [hmim][B(CN)4] (1-hexyl-3-methylimidazolium tetracyanoborate), to work both as a reaction medium and a water-repellent, the phase behaviour of multicomponent systems under high CO2 pressures was studied. The principal alcohol under investigation in this study was 1,4-butanediol. However, in order to verify the applicability of the proposed strategy to the conversion of different diols, experiments were also performed for 1,2-propanediol (1,2-PDO).
Table 1 presents the vapour-liquid equilibrium data for the quaternary system containing carbon dioxide, 1,4-butanediol, [hmim][B(CN)4] and water. As expected, the solubility of carbon dioxide in the liquid phase increased with the increasing pressure. Since the system is composed of four components and presents two phases, it has 4 degrees of freedom. Furthermore, the initial concentration of water in the system was 50 mol% with respect to the alcohol to simulate the progress of the reaction. This value was selected assuming the theoretical 50% conversion of diol to levulinic acid. The ratio of ionic liquid to alcohol was set at 0.3 molar, and 1 by weight. The ionic liquid is expected to play a role of a water-repellent, making it possible to separate formed water from the reaction medium, but also of a solvent, bringing the substrates together by enhancing the solubility of gas in the liquid phase.
Tetracyanoborate-based ionic liquids have been proven to have a high, up to 80 mol %, capacity for carbon dioxide dissolution [24]. However, has already been shown, the presence of water can influence the solubility of carbon dioxide in the ionic liquid, depending on the ionic liquid-water affinity (hydrophobic vs. hydrophilic) [25]. Moreover, a small addition of water may lead to a significant change in the phase behaviour of the system containing ionic liquid, alcohol and carbon dioxide, leading to a phase separation [26].
As can be seen in Figure 2, even though the comparison is not straightforward due to a different number of components, the mixture of [hmim][B(CN)4] and 1,4-butanediol in the quaternary system is able to dissolve lower, but still considerable, amounts of carbon dioxide in the liquid phase when compared to the binary (IL+CO2) system [24]. In addition to the quaternary system, the binary (CO2+1,4-BDO) and ternary (CO2+1,4-BDO+[hmim][B(CN)4]) systems were studied. Unfortunately, it was impossible to take representative liquid samples from these systems due to the high viscosity of 1,4-butanediol.
The vapour-liquid equilibrium data for the ternary (CO2+1,4-BDO+[hmim][B(CN)4]) system is given in Table 2. The analysis of the gas phase of the binary (CO2+1,4-butanediol) system revealed that no alcohol passes to this phase in the studied pressure range. Inomata et al. [27] investigated the phase behaviour of isomers, e.g., 1,2- and 1,3-butanediol, and showed that (1,2-butanediol+CO2) mixture has a smaller coexistence region (as seen in Figure 2). The authors suggested that 1,3-butanediol has less affinity for carbon dioxide due to the two hydroxyl groups located at both ends of the molecule having a larger effective surface area in comparison with –OH groups of 1,2-butanediol. The term “effective surface area” was introduced in their work in order to distinguish between the behaviour of isomers using the modified group contribution equation of state. The new parameter takes into account the connecting positions of the group species, and not only their type and number, as usually considered by group contribution prediction methods. The longer distance between hydroxyl groups in 1,4-butanediol may suggest the even smaller affinity for CO2 and explain the absence of this polyhydric alcohol in the gas phase under the conditions studied.
In order to check the versatility of the proposed strategy, analogous vapour-liquid equilibrium measurements were performed for a diol that is more soluble in the dense carbon dioxide phase, i.e., 1,2-propanediol (1,2-PDO). Chyliński et al. [28] studied the solubility of 1,2-propanediol in the gas phase of the binary (CO2+1,2-PDO) system in the temperature range 311–333 K and pressures up to 8 MPa. The measured solubility was not higher than 0.04 mol% fraction. Knez and co-workers investigated the solubility at three, higher temperatures (398.2, 423.2 and 453.2 K) and pressures ranging from 2.5 to 55 MPa [29]. The authors determined that the solubility of 1,2-propanediol equals, on average, approximately 20 mol%. Table 3 reports the gas phase mole fractions of particular components obtained in this work for the quaternary (CO2+1,2-PDO+[hmim][B(CN)4]+H2O) system, at 313.2 K.
In Figure 3 it can be seen that for both quaternary systems, (CO2 +1,4-BDO +[hmim][B(CN)4] +H2O) and (CO2+1,2-PDO+[hmim][B(CN)4]+H2O), the amount of water that passes to the light gas phase is higher than that data presented in the literature for the binary (CO2+H2O) system [30]. Thus, the presence of ionic liquid and alcohol influences positively the removal of water from the liquid phase. For the purpose of comparison, the values plotted in Figure reflect the ratio of the water-to-carbon dioxide sampled, at particular conditions, from the gas phase. The initial compositions of the systems investigated comprise the same amounts of diol, ionic liquid, and water.
Unfortunately, the addition of 50 mol% (with respect to the diol) of water (a polar co-solvent) to the system simultaneously co-extracts the diol to the gas phase. Surprisingly, even the addition of a pure ionic liquid to the 1,4-butanediol causes some removal of the alcohol (only at pressures equal or higher than 16 MPa) from the liquid phase in the ternary (CO2 + 1,4-BDO + [hmim][B(CN)4]) mixture (see Table 1). This is an undesired effect for the alcohol transformation that takes place in the liquid phase. Figure 4 shows the composition of diols in the vapour phase for both quaternary systems and the literature data for the binary (CO2+1,2-PDO) one [28]. Again, for the purpose of comparison, the values plotted reflect the ratio of alcohol-to-carbon dioxide, sampled at particular conditions from the gas phase. Both quaternary systems studied had similar initial compositions concerning the amounts of diol, ionic liquid, and water.
Optimum conditions for alcohol conversion are those in which diol and water are in different phases. In Figure 5, for each of the alcohols investigated such favourable reaction conditions are shaded in grey. For the quaternary (CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O) system at 313.2 K and pressures below 14 MPa, 1,4-butanediol remains in the liquid phase and the undesired by-product (water) is expelled to the gas phase, positively shifting the reaction equilibrium. For the quaternary (CO2 + 1,2-PDO + [hmim][B(CN)4] + H2O) system these conditions exist at the same temperature for pressures lower than 10 MPa.
The results obtained in this study serve as a proof of concept that it is possible to use [hmim][B(CN)4] as a reaction medium and water-repellent at the same time. The combination of high-pressure carbon dioxide with ionic liquid can potentially prevent the use of expensive distillation operation in levulinic acid synthesis from 1,4 BDO. In a continuous mode of operation, additional benefits emerge from an unusual, highly asymmetrical phase behaviour of the biphasic (CO+IL) system. The desired product can be continuously extracted, in this particular case together with water, without any solvent cross-contamination keeping ionic liquid with a catalyst inside a reactor for reutilisation [31,32]. The approach presented certainly still requires an economic evaluation. Although it looks very promising, an overall cost associated with the usage of large volumes of ionic liquid may limit its application. Nonetheless, it is expected that the cost of ionic liquids will steadily decrease, along with the increasing demand for them. Plus, in (CO2+IL) systems ionic liquid can be easily recycled and reused, minimising the relevance of its initial cost.

4. Conclusions

This work proposes a high-pressure biphasic (CO2+hydrophobic IL) system as an effective reaction media for carrying out levulinic acid production from biomass-derived 1,4-butanediol. The reaction under investigation has a severe equilibrium limitation caused by the formation of high quantities of water as a by-product. Vapour-liquid equilibrium results now obtained for the quaternary systems (diol + IL + CO2 + water) show a considerable increase in the water mol fraction of the CO2 rich-gaseous phase. Tetracyanoborate-based ionic liquid proved to be capable of simultaneously enhancing the carbon dioxide concentration in a liquid phase and acting as a water-repellent agent.

Author Contributions

M.E.Z. and A.V.M.N. conceived and designed the experiments; M.E.Z. and A.B.P. performed the experiments; M.E.Z., A.V.M.N. and M.F.C.G.d.S. analyzed the data; M.E.Z. wrote the paper and A.V.M.N. and M.F.C.G.d.S. revised it; A.V.M.N. and M.F.C.G.d.S. acquired the financial support for the project. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by Fundação para a Ciência e Tecnologia FCT/MCTES through project PTDC/EQU-EPQ/31926/2017, UID/QUI/50006/2019 of Associate Laboratory for Green Chemistry- LAQV and UIDB/00100/2020 of Centro de Química Estrutural. A.V.M. Nunes is thankful to FCT/MCTES for contract IF/01374/2014. M.E. Zakrzewska is thankful to FCT/MCTES for the postdoctoral grant SFRH/BPD/122655/2016. The NMR spectrometers at FCT NOVA are part of Rede Nacional de RMN (PTNMR), supported by Fundação para a Ciência e a Tecnologia (ROTEIRO/0031/2013 - PINFRA/22161/2016) (co-financed by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC).

Conflicts of Interest

The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

References

  1. Novamont Press Release. Available online: https://www.novamont.com/eng/read-press-release/mater-biotech/ (accessed on 17 October 2019).
  2. Yim, H.; Haselbeck, R.; Niu, W.; Pujol-Baxley, C.; Burgard, A.; Boldt, J.; Khandurina, J.; Trawick, J.D.; Osterhout, R.E.; Stephen, R.; et al. Metabolic engineering of Escherichia coli for direct production of 1,4-butanediol. Nat. Chem. Biol. 2011, 7, 445. [Google Scholar] [CrossRef]
  3. Burgard, A.; Burk, M.J.; Osterhout, R.; Van Dien, S.; Yim, H. Development of a commercial scale process for production of 1,4-butanediol from sugar. Curr. Opin. Biotechnol. 2016, 42, 118. [Google Scholar] [CrossRef] [PubMed]
  4. Biddy, M.J.; Scarlata, C.; Kinchin, C. Chemicals from Biomass: A Market Assessment of Bioproducts with Near-Term Potential, National Renewable Energy Laboratory Technical Report. Available online: www.nrel.gov/publications (accessed on 17 October 2019).
  5. Rosales-Calderon, O.; Arantes, V. A review on commercial-scale high-value products that can be produced alongside cellulosic ethanol. Biotechnol. Biofuels 2019, 12, 240. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  6. Koytsoumpa, E.I.; Bergins, C.; Kakaras, E. The CO2 economy: Review of CO2 capture and reuse technologies. J. Supercrit. Fluids 2018, 132, 3. [Google Scholar] [CrossRef]
  7. Artz, J.; Müller, T.E.; Thenert, K. Sustainable conversion of carbon dioxide: An integrated review of catalysis and life cycle assessment. Chem. Rev. 2018, 118, 434. [Google Scholar] [CrossRef] [PubMed]
  8. Rahman, F.A.; Aziz, M.M.A.; Saidur, R.; Bakar, W.A.W.A.; Hainin, M.R.; Putrajaya, R.; Hassan, N.A. Pollution to solution: Capture and sequestration of carbon dioxide (CO2) and its utilization as a renewable energy source for a sustainable future. Renew. Sustain. Energy Rev. 2017, 71, 112. [Google Scholar] [CrossRef]
  9. Al-Mamoori, A.; Krishnamurthy, A.; Rownaghi, A.A.; Rezaei, F. Carbon Capture and Utilization Update. Energy Technol. 2017, 5, 834. [Google Scholar] [CrossRef] [Green Version]
  10. Yang, Z.; Gao, X.; Liu, Z. Synthesis of chemicals using CO2 as a building block under mild Conditions. Curr. Opin. Green Sustain. Chem. 2016, 1, 13. [Google Scholar] [CrossRef]
  11. Roh, K.; Frauzem, R.; Gani, R.; Lee, J.H. Process systems engineering issues and applications towards reducing carbon dioxide emissions through conversion technologies. Chem. Eng. Res. Des. 2016, 116, 27. [Google Scholar] [CrossRef]
  12. Putra, Z.A.; Kurnia, J.C.; Sasmito, A.P.; Muraza, O. Process design and techno-economic analysis of ethyl levulinate production from carbon dioxide and 1,4-butanediol as an alternative biofuel and fuel additive. Int. J. Energy Res. 2019, 43, 5932. [Google Scholar] [CrossRef]
  13. Leal Silva, J.F.; Grekin, R.; Mariano, A.P.; Maciel Filho, R. Making Levulinic Acid and Ethyl Levulinate Economically Viable: A Worldwide Technoeconomic and Environmental Assessment of Possible Routes. Energy Technol. 2018, 6, 613. [Google Scholar] [CrossRef]
  14. Blanchard, L.A.; Hancu, D.; Beckman, E.J.; Brennecke, J.F. Green processing using ionic liquids and CO2. Nature 1999, 399, 28. [Google Scholar] [CrossRef]
  15. Ahosseini, A.; Ortega, E.; Sensenich, B.; Scurto, A.M. Viscosity of n-Alkyl-3-methyl-imidazolium Bis(trifluoromethylsulfonyl)amide Ionic Liquids Saturated with Compressed CO2. Fluid Phase Equilibr. 2009, 286, 72. [Google Scholar] [CrossRef]
  16. Tomida, D.; Kenmochi, S.; Qiao, K.; Bao, Q.; Yokoyama, C. Viscosity of Ionic Liquid Mixtures of 1-Alkyl-3-methylimidazolium Hexafluorophosphate + CO2. Fluid Phase Equilibr. 2011, 307, 185. [Google Scholar] [CrossRef]
  17. Moosavi, M.; Rostami, A.A. Densities, viscosities, refractive indices, and excess properties of aqueous 1,2-etanediol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol binary mixtures. J. Chem. Eng. Data 2017, 62, 156. [Google Scholar] [CrossRef]
  18. Domańska, U.; Królikowski, M. Extraction of butan-1-ol from water with ionic liquids at T = 308.15 K. J. Chem. Thermodyn. 2012, 53, 108. [Google Scholar] [CrossRef]
  19. Stoffers, M.; Górak, A. Continuous multi-stage extraction of n-butanol from aqueous solutions with 1-hexyl-3-methylimidazolium tetracyanoborate. Sep. Purif. Technol. 2013, 120, 415. [Google Scholar] [CrossRef]
  20. Rebocho, S.; Nunes, A.V.M.; Najdanovic-Visak, V.; Barreiros, S.; Simões, P.; Paiva, A. High pressure vapor–liquid equilibrium for the ternary system ethanol (±) menthol/carbon dioxide. J. Supercrit. Fluids 2014, 92, 282. [Google Scholar] [CrossRef]
  21. Bogel-Łukasik, R.; Najdanovic-Visak, V.; Barreiros, S.; Nunes da Ponte, M. Distribution Ratios of Lipase-Catalyzed Reaction Products in Ionic Liquid Supercritical CO2 Systems: Resolution of 2-Octanol Enantiomers. Ind. Eng. Chem. Res. 2008, 47, 4473. [Google Scholar] [CrossRef]
  22. Nunes, A.V.M.; Matias, A.A.; Nunes da Ponte, M.; Duarte, C.M.M. Quaternary Phase Equilibria for scCO2 plus Biophenolic Compound plus Water plus Ethanol. J. Chem. Eng. Data 2007, 52, 244. [Google Scholar] [CrossRef]
  23. Nunes, A.V.M.; Nunes da Ponte, M. Phase Equilibrium and Kinetics of O2-Oxidation of Limonene in High Pressure Carbon Dioxide. J. Supercrit. Fluids 2012, 66, 23. [Google Scholar] [CrossRef]
  24. Zakrzewska, M.E.; Nunes da Ponte, M. Volumetric and phase behaviour of mixtures of tetracyanoborate-based ionic liquids with high pressure carbon dioxide. J. Supercrit. Fluids 2016, 113, 31. [Google Scholar] [CrossRef]
  25. Zakrzewska, M.E.; Nunes da Ponte, M. Influence of Water on the Carbon Dioxide Solubility in [OTf]- and [eFAP]-Based Ionic Liquids. J. Chem. Eng. Data 2018, 63, 907. [Google Scholar] [CrossRef]
  26. Najdanovic-Visak, V.; Serbanovic, A.; Esperança, J.M.S.S.; Guedes, H.J.R.; Rebelo, L.P.N.; Nunes da Ponte, M. Supercritical Carbon Dioxide-Induced Phase Changes in (Ionic Liquid, Water and Ethanol Mixture) Solutions: Application to Biphasic Catalysis. ChemPhysChem 2003, 4, 520. [Google Scholar] [CrossRef] [PubMed]
  27. Inomata, H.; Kondo, A.; Kakehashi, H. Vapor–liquid equilibria for CO2–fermentation alcohol mixtures Application of a new group contribution equation of state to isomeric compounds. Fluid Phase Equilibr. 2005, 228–229, 335. [Google Scholar] [CrossRef]
  28. Chyliński, K.; Gregorowicz, J. Solubilities of 1-propanol and 1,2-propanediol in supercritical carbon dioxide. New analytical procedure and measurements. Fluid Phase Equilibr. 1998, 143, 163. [Google Scholar] [CrossRef]
  29. Škerget, M.; Čuček, D.; Knez, Ž. Phase equilibria of the propylene glycol/CO2 and propylene glycol/ethanol/CO2 systems. J. Supercrit. Fluids 2014, 95, 129. [Google Scholar] [CrossRef]
  30. King, M.B.; Mubarak, A.; Kim, J.D.; Bott, T.R. The Mutual Solubilities of Water with Supercritical and Liquid Carbon Dioxide. J. Supercrit. Fluids 1992, 5, 296. [Google Scholar] [CrossRef]
  31. Han, X.; Poliakoff, M. Continuous reactions in supercritical carbon dioxide: Problems, solutions and possible ways forward. Chem. Soc. Rev. 2012, 41, 1428. [Google Scholar] [CrossRef]
  32. Stouten, S.C.; Noël, T.; Wang, Q.; Hessel, V. Catalyst retention in continuous flow with supercritical carbon dioxide. Chem. Eng. Process. 2014, 83, 26. [Google Scholar] [CrossRef]
Carbon 06 00009 g001 550
Figure 1. The two-step synthesis of ethyl levulinate from carbon dioxide and 1,4-butanediol.
Figure 1. The two-step synthesis of ethyl levulinate from carbon dioxide and 1,4-butanediol.
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Figure 2. Vapour-liquid equilibrium studies for the quaternary ●, CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O [this work] and binary ×, CO2+1,2-BDO and +, CO2 + 1,3-BDO (Reproduced with permission from [27] Copyright Elsevier, 2004), ○, CO2 + [hmim][B(CN)4] (Reproduced with permission from [24] Copyright Elsevier, 2016) systems, at 313,15 K; the right hand side represents an enlargement of the gas phase regime.
Figure 2. Vapour-liquid equilibrium studies for the quaternary ●, CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O [this work] and binary ×, CO2+1,2-BDO and +, CO2 + 1,3-BDO (Reproduced with permission from [27] Copyright Elsevier, 2004), ○, CO2 + [hmim][B(CN)4] (Reproduced with permission from [24] Copyright Elsevier, 2016) systems, at 313,15 K; the right hand side represents an enlargement of the gas phase regime.
Carbon 06 00009 g002
Carbon 06 00009 g003 550
Figure 3. The relative amount of water in the gas phase for the quaternary □, (CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O) or ∆, (CO2 + 1,2-PDO + [hmim][B(CN)4] + H2O) [this work], and the binary ◊, (CO2+H2O) (Reproduced with permission from [30] Copyright Elsevier, 1992) systems, at 313.2 K.
Figure 3. The relative amount of water in the gas phase for the quaternary □, (CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O) or ∆, (CO2 + 1,2-PDO + [hmim][B(CN)4] + H2O) [this work], and the binary ◊, (CO2+H2O) (Reproduced with permission from [30] Copyright Elsevier, 1992) systems, at 313.2 K.
Carbon 06 00009 g003
Carbon 06 00009 g004 550
Figure 4. The relative amount of alcohol in the gas phase for the quaternary ■, (CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O) or ▲, (CO2 + 1,2-PDO + [hmim][B(CN)4] + H2O) [this work], and binary ♦, (CO2+1,2-PDO) (Reproduced with permission from [28] Copyright Elsevier, 1998) systems, at 313.2 K.
Figure 4. The relative amount of alcohol in the gas phase for the quaternary ■, (CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O) or ▲, (CO2 + 1,2-PDO + [hmim][B(CN)4] + H2O) [this work], and binary ♦, (CO2+1,2-PDO) (Reproduced with permission from [28] Copyright Elsevier, 1998) systems, at 313.2 K.
Carbon 06 00009 g004
Carbon 06 00009 g005 550
Figure 5. The relative amount of water vs. diol (mA) in the gas phase of the quaternaries (a) (CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O) or (b) (CO2 + 1,2-PDO + [hmim][B(CN)4] + H2O) systems at 313.2 K; ■, 1,4-BDO and □, H2O; ▲, 1,2-PDO and ∆, H2O.
Figure 5. The relative amount of water vs. diol (mA) in the gas phase of the quaternaries (a) (CO2 + 1,4-BDO + [hmim][B(CN)4] + H2O) or (b) (CO2 + 1,2-PDO + [hmim][B(CN)4] + H2O) systems at 313.2 K; ■, 1,4-BDO and □, H2O; ▲, 1,2-PDO and ∆, H2O.
Carbon 06 00009 g005
Table
Table 1. Vapour-liquid equilibrium data for the quaternary (CO2 +1,4 BDO +[hmim][B(CN)4] +H2O) system at 313.2 K 1.
Table 1. Vapour-liquid equilibrium data for the quaternary (CO2 +1,4 BDO +[hmim][B(CN)4] +H2O) system at 313.2 K 1.
P/MPaxCO2x1,4-BDOxILxH2OyCO2y1,4-BDOyILyH2O
80.3240.0720.4750.1290.9870ndnd0.0130
100.4380.0470.3960.1190.9842ndnd0.0158
120.4670.0420.3910.1000.9817ndnd0.0183
140.5510.0280.3530.0670.98190.00198nd0.0161
160.6160.0170.3100.0570.98560.00183nd0.0126
180.6460.0140.2990.0410.98370.00179nd0.0145
1 molar ratio of IL to diol = 0.3, molar ratio of H2O to diol = 0.5; nd – not detected; u(T) = 0.1 K, u(P) = 0.007 MPa, u(xCO2) = 0.031, u(x1,4-BDO) = 0.009, u(xH2O) = 0.004, u(xIL) = 0.019, u(yCO2) = 0.0002, u(y1,4-BDO) = 0.00005, u(yH2O) = 0.0001.
Table
Table 2. Vapour-liquid equilibrium data for the ternary (CO2+1,4-BDO+[hmim][B(CN)4]) system at 313.2 K 1 (data presented refer to the gas phase).
Table 2. Vapour-liquid equilibrium data for the ternary (CO2+1,4-BDO+[hmim][B(CN)4]) system at 313.2 K 1 (data presented refer to the gas phase).
P/MPa yCO2y1,4-BDOyIL
81.0000ndnd
101.0000ndnd
121.0000ndnd
141.0000ndnd
160.98830.01168nd
180.99210.00795nd
1 molar ratio of IL to diol = 0.3; nd – not detected; u(T) = 0.1 K, u(P) = 0.007 MPa, u(yCO2) = 0.0002, u(y1,4-BDO) = 0.00005.
Table
Table 3. Vapour-liquid equilibrium data for the quaternary (CO2+1,2-PDO+[hmim][B(CN)4]+H2O) system at 313.2 K 1 (data presented refer to the gas phase).
Table 3. Vapour-liquid equilibrium data for the quaternary (CO2+1,2-PDO+[hmim][B(CN)4]+H2O) system at 313.2 K 1 (data presented refer to the gas phase).
P/MPayCO2y1,4-BDOyH2O
80.9877nd0.0123
100.97440.001480.0242
120.96570.002010.0324
140.98520.002390.0125
160.98060.002650.0168
180.98280.002960.0142
1 molar ratio of IL to diol = 0.3, molar ratio of H2O to diol = 0.5; nd – not detected; u(T) = 0.1 K, u(P) = 0.007 MPa, u(yCO2) = 0.0002, u(y1,4-BDO) = 0.00005, u(yH2O) = 0.0001.

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Zakrzewska, M.E.; Paninho, A.B.; Guedes da Silva, M.F.C.; Nunes, A.V.M. High-Pressure Phase Equilibrium Studies of Multicomponent (Alcohol-Water-Ionic Liquid-CO2) Systems. C 2020, 6, 9. https://doi.org/10.3390/c6010009

AMA Style

Zakrzewska ME, Paninho AB, Guedes da Silva MFC, Nunes AVM. High-Pressure Phase Equilibrium Studies of Multicomponent (Alcohol-Water-Ionic Liquid-CO2) Systems. C. 2020; 6(1):9. https://doi.org/10.3390/c6010009

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Zakrzewska, Małgorzata E., Ana B. Paninho, M. Fátima C. Guedes da Silva, and Ana V. M. Nunes. 2020. "High-Pressure Phase Equilibrium Studies of Multicomponent (Alcohol-Water-Ionic Liquid-CO2) Systems" C 6, no. 1: 9. https://doi.org/10.3390/c6010009

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