Homogeneous Catalysis and Catalyst Recovery Using Supercritical Carbon Dioxide and Ionic Liquids

Jessop, Philip G.

doi:10.5059/yukigoseikyokaishi.61.484

Cited by 16 publications

(8 citation statements)

References 8 publications

(5 reference statements)

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“…First, we have shown that it is possible to recover a variety of solutes, including relatively low-volatility solutes, from ILs by extraction with CO 2 . − Obviously, phase behavior is important for this application. Second, a number of researchers have adopted the idea of IL/CO 2 biphasic systems for reaction/separation systems. − In some cases the reaction is simply followed by extraction with supercritical CO 2 , but in other cases the CO 2 plays an integral role in facilitating both the reaction and the separation or even acts as a reactant. − Once again, understanding the phase behavior of CO 2 with various ILs is vital to designing and understanding these systems. Third, we and others have shown that ILs have potential uses in separating CO 2 from other gases, another application where CO 2 solubilities in ILs are important. − …”

Section: Introductionmentioning

confidence: 99%

“…Second, a number of researchers have adopted the idea of IL/CO 2 biphasic systems for reaction/separation systems. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] In some cases the reaction is simply followed by extraction with supercritical CO 2 , but in other cases the CO 2 plays an integral role in facilitating both the reaction and the separation or even acts as a reactant. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Once again, understanding the phase behavior of CO 2 with various ILs is vital to designing and understanding these systems.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] In some cases the reaction is simply followed by extraction with supercritical CO 2 , but in other cases the CO 2 plays an integral role in facilitating both the reaction and the separation or even acts as a reactant. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Once again, understanding the phase behavior of CO 2 with various ILs is vital to designing and understanding these systems. Third, we and others have shown that ILs have potential uses in separating CO 2 from other gases, another application where CO 2 solubilities in ILs are important.…”

Section: Introductionmentioning

confidence: 99%

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High-Pressure Phase Behavior of Carbon Dioxide with Imidazolium-Based Ionic Liquids

et al. 2004

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Previously we have shown that supercritical carbon dioxide can be used to extract organics from ionic liquids (ILs). Subsequently, ionic liquids/carbon dioxide biphasic solutions have been used for a variety of homogeneously catalyzed reactions. Therefore, an understanding of the phase behavior of carbon dioxide with ionic liquids is needed to design extraction and reaction processes necessary for these applications. We present measurements of the solubility of carbon dioxide in 10 different imidazolium-based ionic liquids at 25, 40, and 60 °C and pressures to 150 bar. As expected, the solubility increases with increasing pressure and decreases with increasing temperature for all the ILs investigated. To investigate the influence of the anion, seven of the ILs studied have 1-butyl-3-methylimidazolium ([bmim]) as the cation. The anions are dicyanamide ([DCA]), nitrate ([NO3]), tetrafluoroborate ([BF4]), hexafluorophosphate ([PF6]), trifuoromethanesulfonate ([TfO]), bis(trifluoromethylsulfonyl)imide ([Tf2N]), and tris(trifluoromethylsulfonyl)methide ([methide]). The other ILs considered in the study, chosen to investigate the influence of varying number and length of alkyl chains on the cation, include 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf2N]), 2,3-dimethyl-1-hexylimidazolium bis(trifluoromethylsulfonyl)imide ([hmmim][Tf2N]), and 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([omim][Tf2N]). Results show that the solubility of carbon dioxide is strongly dependent on the choice of anion. In particular, CO2 solubility is greater in ILs with anions, such as [Tf2N] and [methide], which contain fluoroalkyl groups. Also, we observe that an increase in the alkyl chain length on the cation increases the CO2 solubility marginally.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-Pressure Phase Behavior of Carbon Dioxide with Imidazolium-Based Ionic Liquids

et al. 2004

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“…The phase behavior of CO 2 with ionic liquids (ILs) is important for the development of several potential IL applications. Since we first showed that CO 2 was soluble in ILs and could be used to extract organic solutes, − IL/CO 2 systems have been demonstrated for various catalytic reactions. − In some cases, CO 2 is used to extract the product from the IL, leaving behind the catalyst and the IL for reuse. Others have adopted IL/CO 2 continuous flow systems, where CO 2 is used to deliver the substrates to the IL/catalyst phase and extract the products.…”

Section: Introductionmentioning

confidence: 99%

Improving Carbon Dioxide Solubility in Ionic Liquids

et al. 2007

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Previously we showed that CO2 could be used to extract organic molecules from ionic liquids without contamination of the ionic liquid. Consequently a number of other groups demonstrated that ionic liquid/CO2 biphasic systems could be used for homogeneously catalyzed reactions. Large differences in the solubility of various gases in ionic liquids present the possibility of using them for gas separations. More recently we and others have shown that the presence of CO2 increases the solubility of other gases that are poorly soluble in the ionic liquid phase. Therefore, a knowledge and understanding of the phase behavior of these ionic liquid/CO2 systems is important. With the aim of finding ionic liquids that improve CO2 solubility and gaining more information to help us understand how to design CO2-philic ionic liquids, we present the low- and high-pressure measurements of CO2 solubility in a range of ionic liquids possessing structures likely to increase the solubility of CO2. We examined the CO2 solubility in a number of ionic liquids with systematic increases in fluorination. We also studied nonfluorinated ionic liquids that have structural features known to improve CO2 solubility in other compounds such as polymers, for example, carbonyl groups and long alkyl chains with branching or ether linkages. Results show that ionic liquids containing increased fluoroalkyl chains on either the cation or anion do improve CO2 solubility when compared to less fluorinated ionic liquids previously studied. It was also found that it was possible to obtain similar, high levels of CO2 solubility in nonfluorous ionic liquids. In agreement with our previous results, we found that the anion frequently plays a key role in determining CO2 solubility in ionic liquids.

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“…Third, a number of researchers have conducted reactions in IL/CO 2 mixtures. [4][5][6][7][10][11][12][13][14][15][16][17][18][19][20] For instance, Cole-Hamilton has shown the utility of performing hydroformylation reactions in an IL/ CO 2 biphasic flow reactor. 19 In this situation, the solvent strength of the IL/CO 2 mixtures will determine the range of feasible reactant and product compositions.…”

Section: Introductionmentioning

confidence: 99%