A model to predict maximum tolerable temperatures of metal-oxide-supported 1- n -butyl-3-methylimidazolium based ionic liquids

Akçay, Aslı; Babucci, Melike; Balci, Volkan; Uzun, Alper

doi:10.1016/j.ces.2014.11.038

Cited by 21 publications

(37 citation statements)

References 43 publications

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“…1,51 Such a decrease in interionic interactions results in an increase in the thermal stability limits, as shown before. 28,29 Here, thermal stability limits of metaloxide-supported [ 4 ], on the other hand, have T′ onset values of 209 and 180°C, respectively, indicating an opposite trend, which is most probably originated by the basic character of MgO. We infer that, with a decrease in interionic interactions, the hydrogen abstraction ability of MgO becomes the dominant factor, leading to a decrease in the thermal stability limit.…”

Section: Resultsmentioning

confidence: 83%

“…43 To elucidate the effect of heating rate, we performed measurements at a heating rate of 2°C/min on metal-oxide-supported ILs and reproduced the same T′ onset results within ±3°C measurement error as the ones measured with a heating rate of 10°C/min (as given in the SI). 28 Thus, we infer that the artifacts of relatively high heating rate in our TGA measurements are less pronounced on these metal-oxide supported samples with low IL loading than the case with bulk ILs, especially when considering T′ onset , which provides more conservative results than T onset . However, we note that these values are rather short-term stability limits indicating the highest temperature that the IL/metal-oxide systems can tolerate for short-time periods.…”

Section: Resultsmentioning

confidence: 93%

“…For instance, the ν(C2H) value of bulk [BMIM]- [BF 4 ] (3122 cm −1 ) is higher than that of [BMIM][DBP] (3077 cm −1 ), while their T′ onset values on SiO 2 are 331 and 222°C, respectively. 28 These results indicate that a high C2H bonding strength significantly reduces the interionic energies, resulting in a high thermal stability on SiO 2. We illustrated a direct dependence of the T′ onset of nine metal-oxide-supported [BMIM] + -based ILs on ν(C2H).…”

Section: [Bf 4 ] (403°c) and [Cpmim]-[bf 4 ] (265°c) And Stated That mentioning

confidence: 93%

“…Thermal stability limits of the ILs decreased in the following order of anions: [NTf 2 ] − > [TfO] − ∼ [SbF 6 ] − ∼ [BF 4 ] − > [HSO 4 ] − > [TOS] − > [OS] − > [DBP] − > [Ac] − , accompanied by a decrease in ν(C2H) frequency 28. Here, we extend this study to metal-oxide-supported ILs with cations other than[BMIM] + (Table 1 and Figure 1).…”

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confidence: 96%

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Thermal Stability Limits of Imidazolium Ionic Liquids Immobilized on Metal-Oxides

et al. 2015

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Thermal stability limits of 33 imidazolium ionic liquids (ILs) immobilized on three of the most commonly used high surface area metal-oxides, SiO2, γ-Al2O3, and MgO, were investigated. ILs were chosen from a family of 13 cations and 18 anions. Results show that the acidity of C2H of an imidazolium ring is one of the key factors controlling the thermal stability. An increase in C2H bonding strength of ILs leads to an increase in their stability limits accompanied by a decrease in interionic energy. Systematic changes in IL structure, such as changes in electronic structure and size of anion/cation, methylation on C2 site, and substitution of alkyl groups on the imidazolium ring with functional groups have significant effects on thermal stability limits. Furthermore, thermal stability limits of ILs are influenced strongly by acidic character of the metal-oxide surface. Generally, as the point of zero charge (PZC) of the metal-oxide increases from SiO2 to MgO, the interactions of IL and metal-oxide dominate over interionic interactions, and metal-oxide becomes the significant factor controlling the stability limits. However, thermal stability limits of some ILs show the opposite trend, as the chemical activities of the cation functional group or the electron donating properties of the anion alter IL/metal-oxide interactions. Results presented here can help in choosing the most suitable ILs for materials involving ILs supported on metal-oxides, such as for supported ionic liquid membranes (SILM) in separation applications or for solid catalyst with ionic liquid layer (SCILL) and supported ionic liquid phase (SILP) catalysts in catalysis.

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Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 93%

Section: [Bf 4 ] (403°c) and [Cpmim]-[bf 4 ] (265°c) And Stated That mentioning

confidence: 93%

mentioning

confidence: 96%

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Thermal Stability Limits of Imidazolium Ionic Liquids Immobilized on Metal-Oxides

et al. 2015

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“…22 However, gas separation performance of Cu-BTC was negatively affected due to the interactions of ILs with the open metals sites available in Cu-BTC. Therefore, we decided to study the incorporation of ILs in a different MOF that have saturated metal sites and 6 ] was incorporated into the pores of ZIF-8 to investigate the separation performance of resulting composite. 23 Remarkable improvements in selectivities were found especially for CO 2 /CH 4 and CO 2 /N 2 separations at low pressures.…”

Section: Introductionmentioning

confidence: 99%

Improving Gas Separation Performance of ZIF-8 by [BMIM][BF₄] Incorporation: Interactions and Their Consequences on Performance

et al. 2017

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Gas separation performance of zeolitic imidazolate framework (ZIF-8) was improved by incorporating an ionic liquid (IL), 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]). Detailed characterization based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed that the morphology of ZIF-8 remains intact upon IL incorporation up to 28 wt%. Thermogravimetric analysis indicated the presence of direct interactions between the IL and metal organic framework (MOF). FTIR spectroscopy illustrated that the anion of the IL was shared between the imidazolate framework and[BMIM] + cation. Adsorption isotherms of CO 2 , CH 4 , and N 2 measured for pristine ZIF-8 and IL-loaded ZIF-8 samples, complemented by Grand Canonical Monte Carlo (GCMC) simulations, showed that these interactions influence the gas uptake performance of ZIF-8. CH 4 and N 2 uptakes decreased in the whole pressure range, while CO 2 uptake first increased by approximately 9% at 0.1 bar in 20 wt% IL-loaded sample, and then, decreased as in the case of other gases. As a result of these changes in gas uptakes occurring at different extend, the corresponding CO 2 /CH 4 , CO 2 /N 2 , and CH 4 /N 2 selectivities enhanced especially at low pressure regime upon IL incorporation. Results showed that CO 2 /CH 4 selectivity increased from 2.2 to 4, while CO 2 /N 2 selectivity more than doubled from 6.5 to 13.3, and CH 4 /N 2 selectivity improved from 3 to 3.4 at 0.1 bar at an IL loading of 28 wt%. The heat of adsorption values (Q st ) measured and simulated for each gas on each sample indicated that interactions between the IL and ZIF-8 strongly influence the gas adsorption behaviors. The change in Q st of CO 2 upon IL-incorporation was more significant than that of other gases, leading to an almost doubling of CO 2 selectivity over CH 4 and N 2 , specifically at low pressures. On the other hand, the selectivity improvement was lost at high pressures because of a strong decrease in the available pore space due to the presence of IL in ZIF-8. These results suggest that such IL/MOF combinations with tunable structures have huge potential towards high performance gas separation applications.

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Palladium‐Mediated Ethylation of the Imidazolium Cation Monitored In Operando on a Solid Catalyst with Ionic Liquid Layer

et al. 2016

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The ionic liquid 1‐ethyl‐3‐methylimidazolium ethylsulfate [EMIM][EtOSO3] was supported on Pd‐Al2O3 to yield a solid catalyst with ionic liquid layer (SCILL) material. During the hydrogenation of ethene, it was found that ethene was incorporated into the imidazolium moiety in a reaction catalyzed by the palladium surface. The formation of 1,2‐diethyl‐3‐methylimidazolium ethylsulfate was confirmed ex situ by means of NMR spectroscopy. Moreover, the reaction itself could be monitored in situ by diffuse reflection infrared Fourier transformation (DRIFT) spectroscopy. A reaction mechanism involving surface carbene species was proposed on the basis of the analytical data.

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A model to predict maximum tolerable temperatures of metal-oxide-supported 1- n -butyl-3-methylimidazolium based ionic liquids

Cited by 21 publications

References 43 publications

Thermal Stability Limits of Imidazolium Ionic Liquids Immobilized on Metal-Oxides

Thermal Stability Limits of Imidazolium Ionic Liquids Immobilized on Metal-Oxides

Improving Gas Separation Performance of ZIF-8 by [BMIM][BF₄] Incorporation: Interactions and Their Consequences on Performance

Palladium‐Mediated Ethylation of the Imidazolium Cation Monitored In Operando on a Solid Catalyst with Ionic Liquid Layer

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A model to predict maximum tolerable temperatures of metal-oxide-supported 1- n -butyl-3-methylimidazolium based ionic liquids

Cited by 21 publications

References 43 publications

Thermal Stability Limits of Imidazolium Ionic Liquids Immobilized on Metal-Oxides

Thermal Stability Limits of Imidazolium Ionic Liquids Immobilized on Metal-Oxides

Improving Gas Separation Performance of ZIF-8 by [BMIM][BF4] Incorporation: Interactions and Their Consequences on Performance

Palladium‐Mediated Ethylation of the Imidazolium Cation Monitored In Operando on a Solid Catalyst with Ionic Liquid Layer

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Improving Gas Separation Performance of ZIF-8 by [BMIM][BF₄] Incorporation: Interactions and Their Consequences on Performance