Ionic liquid layer on Pd/C catalyst: Membrane-like effect on the selectivity for multistep hydrogenation reactions

Nassor, Evelisy C. O.; Tristão, Juliana Cristina; Santos, Eduardo N. dos; Moura, Flávia C.C.; Lago, Rochel M.; Araújo, Maria Helena

doi:10.1016/j.molcata.2012.05.019

Cited by 13 publications

(6 citation statements)

References 49 publications

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“…The current study utilized six imidazolium ionic liquids to examine their effects on the rheology of HCO. The six ionic liquids were [BMIM] + [Cl] − , [BMIM] + [Br] − , [BMIM] + [HSO 4 ] − , [HMIM] + [Br] − , [HMIM] + [HSO 4 ] − , and [OMIM] + [Cl] − , which were all synthesized according to the literature methods and characterized by 1 H nuclear magnetic resonance (NMR) spectrometry (Bruker Avance 500 MHz spectrometer) using dimethyl sulfoxide (DMSO) or CDCl 3 as the solvent. − Table lists the ILs used in the present work, their abbreviations, and their chemical structures. Before use, all of the ILs were dried under a vacuum (0.1 Pa) at 353 K for 24 h. All six ILs used in the current investigation were tested for their water content using Karl Fischer reagent in a μAquaCal 100 Karl Fischer Titrator (Analab, Gujarat, India).…”

Section: Methodsmentioning

confidence: 99%

Effects of Imidazolium-Based Ionic Liquids on the Rheological Behavior of Heavy Crude Oil under High-Pressure and High-Temperature Conditions

2017

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The production, processing, and transportation of heavy crude oil (HCO) is difficult because of its high viscosity. For practical applications, information on the rheological behavior of HCO plays an important role, especially in flow assurance investigations. In this work, six different imidazolium ionic liquids (ILs) were tested for their effects on the rheological behavior of HCO under high-pressure and high-temperature conditions. The rheological studies were carried out at three different pressures (0.1, 5, and 10 MPa) and four experimental temperatures (298.15, 323.15, 348.15, and 373.15 K). The HCO + IL systems showed favorable viscosity reductions of 26.5% and 31.5% for the systems of HCO + 1-butyl-3-methylimidazolium chloride ([BMIM]+[Cl]−) and HCO + 1-octyl-3-methylimidazolium chloride ([OMIM]+[Cl]−), respectively, at 298.15 K and 0.1 MPa as compared to the pure HCO system. At 298.15 K and 0.1 MPa, the yield stress of the HCO + IL systems was reduced by about 15–20%, whereas when the temperature was increased to 373.15 K, the yield stress decreased in the range of 25–30% as compared to that of neat HCO. The viscoelastic moduli of the HCO sample at 0.1 MPa, 298.15 K, and about 1.5% strain were found to be G′ (storage modulus) ≈ 11 Pa and G″ (loss modulus) ≈ 7 Pa, indicating that the HCO sample was solidlike, whereas for the HCO + IL systems, the G′ and G″ values were reduced to ∼7 and 3 Pa, respectively. The crossover frequency of the HCO + IL systems was reduced to the range of 25–30% as compared to that of pure HCO. From the various measurements, it was observed that the addition of the ILs to the HCO resulted in improved rheological properties compared to those of the pure HCO system. Further, the results of the microscopic investigation also supported the rheological studies, indicating that the addition of the ILs helped to break the large flocculated structures of HCO into smaller spheres. It was also observed that the IL with the longer alkyl chain length provided greater efficiency in the viscosity reduction with favorable viscoelastic behavior.

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Section: Methodsmentioning

confidence: 99%

Effects of Imidazolium-Based Ionic Liquids on the Rheological Behavior of Heavy Crude Oil under High-Pressure and High-Temperature Conditions

2017

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“…Nine aromatic ILs have been synthesized and purified as per methods available in the literature − and have been confirmed using 1 H nuclear magnetic resonance ( 1 H NMR). They are [C 4 mim] + [Cl] − , [C 4 mim] + [PF 6 ] − , [C 4 mim] + [HSO 4 ] − , [C 4 mim] + [H 2 PO 4 ] − , [C 4 mim] + [Br] − , [C 4 mim] + [BF 4 ] − , [C 6 mim] + [Br] − , [C 6 mim] + [HSO 4 ] − , and [C 8 mim] + [Cl] − and are presented in Table .…”

Section: Methodsmentioning

confidence: 99%

Use of Aromatic Ionic Liquids in the Reduction of Surface Phenomena of Crude Oil–Water System and their Synergism with Brine

Sakthivel

Velusamy

Gardas

et al. 2015

Ind. Eng. Chem. Res.

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Enhanced oil recovery is governed primarily by the role of interfacial tension between crude oil and water. Interfacial tension (IFT) of the crude oil−water system is one of the vital factors in the analysis of the capillary forces affecting trapped oil within the reservoir rocks. High salinity and temperature of the reservoirs tend to make researchers search for new surfactants to lower the interfacial tension in crude oil−water systems. The current study hopes to create a move toward solving the above problem through the use of aromatic ionic liquids (ILs) based on imidazolium as the cation and various anions such as [HSO 4 ] − , and [PF 6 ] − in different concentrations. This work involves the study of the effect of concentration, temperature, time, and brine on the fate of surface tension (SFT) of water and interfacial tension of crude oil− water systems. The present study also addresses the trend in the electrical conductivity of ILs in water along with the effect of temperature and concentration of ILs. The study reveals that these ILs are effective in reducing the SFT and IFT of water and crude oil−water systems at high salinity and temperature conditions. In the IFT measurements, a linear decrement with increase in temperature is observed for crude oil−water in the presence of ILs. The interfacial tension of the various imidazolium-based ionic liquids with the crude oil−water system has been measured as a function of temperature by means of the Wilhelmy plate method. The influence of the nature of cation and anion of ionic liquids and of the chain length on the cationic head of the ILs on interfacial tension is also discussed in detail. At increased salinity conditions, unlike classical surfactants, these ILs are found to be more successful. Enhanced efficiency of the drop in IFT using NaCl and IL mixture has been confirmed by measuring the IFT between crude oil and the aqueous solution of IL. The synergism of salt and IL mixture on the reduction of IFT has been observed.

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“…The SCILL concept is, however, still in an early stage of development. Up to now, most studies addressing SCILL catalysts have focused on hydrogenation reactions. ,− Even though an increase in selectivity has been observed in many of them, the total turnover rates were usually lower compared to nonmodified systems because of new diffusion barriers introduced by the IL film and partial poisoning of catalytic sites. In spite of these intriguing results, there are only a few studies that have dealt with the underlying principles of SCILL catalysts on an atomic level, ,− probably in part because the required surface scientific studies are experimentally involved.…”

Section: Introductionmentioning

confidence: 99%

Interactions Between the Room-Temperature Ionic Liquid [C₂C₁Im][OTf] and Pd(111), Well-Ordered Al₂O₃, and Supported Pd Model Catalysts from IR Spectroscopy

et al. 2014

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The interactions between ionic liquids and their supports determine many of their applications. The adsorption of the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate [C2C1Im][OTf] on Pd(111), ordered Al2O3/NiAl(110), and Pd nanoparticles supported on Al2O3/NiAl(110) was investigated under ultrahigh vacuum (UHV) conditions using time-resolved infrared reflection absorption spectroscopy (TR-IRAS). On Pd, the [OTf]− anion stands up with its CF3 group directed toward the vacuum, whereas the anion is less clearly oriented on the oxide. We also find that strong interactions of the IL with the Pd result in migration of the IL from the oxide to the metal nanoparticles.

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Ionic liquid layer on Pd/C catalyst: Membrane-like effect on the selectivity for multistep hydrogenation reactions

Cited by 13 publications

References 49 publications

Effects of Imidazolium-Based Ionic Liquids on the Rheological Behavior of Heavy Crude Oil under High-Pressure and High-Temperature Conditions

Effects of Imidazolium-Based Ionic Liquids on the Rheological Behavior of Heavy Crude Oil under High-Pressure and High-Temperature Conditions

Use of Aromatic Ionic Liquids in the Reduction of Surface Phenomena of Crude Oil–Water System and their Synergism with Brine

Interactions Between the Room-Temperature Ionic Liquid [C₂C₁Im][OTf] and Pd(111), Well-Ordered Al₂O₃, and Supported Pd Model Catalysts from IR Spectroscopy

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Ionic liquid layer on Pd/C catalyst: Membrane-like effect on the selectivity for multistep hydrogenation reactions

Cited by 13 publications

References 49 publications

Effects of Imidazolium-Based Ionic Liquids on the Rheological Behavior of Heavy Crude Oil under High-Pressure and High-Temperature Conditions

Effects of Imidazolium-Based Ionic Liquids on the Rheological Behavior of Heavy Crude Oil under High-Pressure and High-Temperature Conditions

Use of Aromatic Ionic Liquids in the Reduction of Surface Phenomena of Crude Oil–Water System and their Synergism with Brine

Interactions Between the Room-Temperature Ionic Liquid [C2C1Im][OTf] and Pd(111), Well-Ordered Al2O3, and Supported Pd Model Catalysts from IR Spectroscopy

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Interactions Between the Room-Temperature Ionic Liquid [C₂C₁Im][OTf] and Pd(111), Well-Ordered Al₂O₃, and Supported Pd Model Catalysts from IR Spectroscopy