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Xylene

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Xylene - Free Register to Access Experts & Abstracts

Steven L Suib - One of the best experts on this subject based on the ideXlab platform.

  • gas phase total oxidation of benzene toluene ethylbenzene and Xylenes using shape selective manganese oxide and copper manganese oxide catalysts
    Journal of Physical Chemistry C, 2012
    Co-Authors: Homer C Genuino, Saminda Dharmarathna, Eric C Njagi, Steven L Suib
    Abstract:

    Volatile organic compounds (VOCs) continue to be the major source of direct and indirect air pollution. Here, cryptomelane-type octahedral molecular sieve (OMS-2) manganese oxide, amorphous manganese oxide (AMO), and mixed copper manganese oxide (CuO/Mn2O3) nanomaterials were synthesized and, together with commercial MnO2, characterized by various techniques. These catalysts were investigated for gas-phase total oxidation of six VOCs under air atmosphere. Using OMS-2 at 250 °C, the average conversions for toluene, benzene, ethylbenzene, p-Xylene, m-Xylene, and o-Xylene were 75%, 61%, 45%, 23%, 13%, and 8%, respectively, whereas using CuO/Mn2O3, 72%, 44%, 37%, 29%, 27%, and 26%, respectively, were obtained. Generally, the conversion of VOCs to CO2 using the synthesized catalysts increased in the order: o-Xylene ≈ m-Xylene < p-Xylene < ethylbenzene < benzene < toluene. However, using commercial MnO2, benzene (44% conversion) was more reactive than toluene (37%), and the Xylenes showed similar reactivities (...

Pieter L. Pohl - One of the best experts on this subject based on the ideXlab platform.

  • discrimination between o Xylene m Xylene p Xylene and ethylbenzene by host compound r r 2 3 dimethoxy 1 1 4 4 tetraphenylbutane 1 4 diol
    Tetrahedron, 2016
    Co-Authors: Benita Barton, Eric C. Hosten, Pieter L. Pohl
    Abstract:

    Abstract The title host compound (R,R)-(−)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol 3, when recrystallized from each of the isomeric Xylenes and ethylbenzene, formed a 2:1 host:guest complex in each instance. Competition experiments where 3 was recrystallized from various equimolar binary, ternary and quaternary mixtures of these guests indicated that 3 displayed a consistent preference for para-Xylene whenever it was present: when 3 was recrystallized from equimolar binary and ternary mixtures of the Xylenes, the selectivity order was para-Xylene ≫ ortho-Xylene > meta-Xylene while recrystallization from equimolar binary and quaternary mixtures of the Xylenes and ethylbenzene showed a selectivity order of para-Xylene > ethylbenzene > ortho-Xylene > meta-Xylene. Thermal experiments showed that the higher the relative thermal stability of the complex, the higher was the host's preference for it. However, no dominant differences in the strength or nature of intermolecular host-guest interactions could be singled out from crystal data to explain these observations.

  • Discrimination between o-Xylene, m-Xylene, p-Xylene and ethylbenzene by host compound (R,R)-(–)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol
    Tetrahedron, 2016
    Co-Authors: Benita Barton, Eric C. Hosten, Pieter L. Pohl
    Abstract:

    Abstract The title host compound (R,R)-(−)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol 3, when recrystallized from each of the isomeric Xylenes and ethylbenzene, formed a 2:1 host:guest complex in each instance. Competition experiments where 3 was recrystallized from various equimolar binary, ternary and quaternary mixtures of these guests indicated that 3 displayed a consistent preference for para-Xylene whenever it was present: when 3 was recrystallized from equimolar binary and ternary mixtures of the Xylenes, the selectivity order was para-Xylene ≫ ortho-Xylene > meta-Xylene while recrystallization from equimolar binary and quaternary mixtures of the Xylenes and ethylbenzene showed a selectivity order of para-Xylene > ethylbenzene > ortho-Xylene > meta-Xylene. Thermal experiments showed that the higher the relative thermal stability of the complex, the higher was the host's preference for it. However, no dominant differences in the strength or nature of intermolecular host-guest interactions could be singled out from crystal data to explain these observations.

Michael Maes - One of the best experts on this subject based on the ideXlab platform.

  • liquid phase adsorption and separation of Xylene isomers by the flexible porous metal organic framework mil 53 fe
    Chemistry of Materials, 2012
    Co-Authors: Racha El Osta, Abel Carlinsinclair, Nathalie Guillou, Richard I Walton, Frederik Vermoortele, Michael Maes, Dirk De Vos, Franck Millange
    Abstract:

    We report a study of the use of the porous metal–organic framework material MIL-53(Fe), FeIII(OH)0.8F0.2[O2C–C6H4–CO2], for the separation of BTEX mixtures (benzene, toluene, ethylbenzene, and the three Xylene isomers). Crystal structures of the three host:guest materials MIL-53(Fe)[Xylene], where Xylene = the ortho, meta, or para isomer of dimethylbenzene, have been solved and refined from powder X-ray diffraction. Each exhibits a fully expanded form with a variety of host:guest and guest:guest interactions responsible for stabilizing the structure. While the ortho- and meta- isomers present a similar arrangement when occluded in the MIL-53 host, the para-Xylene shows a distinctly different set of interactions with the host. Upon thermal treatment, Xylenes are partially lost to give crystalline phases MIL-53(Fe)[Xylene]0.5, the structures of which have also been solved. The kinetics of uptake of each Xylene by MIL-53(Fe)[H2O], in which the water is replaced by the organic guest, have been studied using t...

  • activation of the metal organic framework mil 47 for selective adsorption of Xylenes and other difunctionalized aromatics
    Physical Chemistry Chemical Physics, 2008
    Co-Authors: Luc Alaerts, Michael Maes, Pierre A Jacobs, Joeri F M Denayer
    Abstract:

    The capacity and selectivity of the metal–organic framework MIL-47 for liquid phase adsorption are shown to heavily depend on the pretreatment of the material, as illustrated in detail by the particular case of selective Xylene adsorption. By totally removing the uncoordinated terephthalic acid from the pores and simultaneously avoiding oxidation to nonporous V2O5, pore volume and uptake of Xylenes can be maximized. The presence of uncoordinated terephthalic acid in the pores improves the selectivity between p- and m-Xylene. Calcination bed thickness and oven geometry influence the optimal calcination procedure. The physicochemical modifications of MIL-47 during its activation are investigated in detail with XRD, SEM, nitrogen physisorption, TGA and diffuse reflectance UV-Vis spectroscopy. Using optimally pretreated MIL-47 as adsorbent for Xylene, ethyltoluene, dichlorobenzene, toluidine or cresol isomers, the para-isomer is in each case preferred over the meta-isomer in pulse chromatographic and batch experiments. The role of stacking in the selective adsorption of these isomers is discussed. In the case of the dichlorobenzenes, the meta- and para-isomers can be separated in a breakthrough experiment with a selectivity of 5.0.

Joeri F M Denayer - One of the best experts on this subject based on the ideXlab platform.

  • activation of the metal organic framework mil 47 for selective adsorption of Xylenes and other difunctionalized aromatics
    Physical Chemistry Chemical Physics, 2008
    Co-Authors: Luc Alaerts, Michael Maes, Pierre A Jacobs, Joeri F M Denayer
    Abstract:

    The capacity and selectivity of the metal–organic framework MIL-47 for liquid phase adsorption are shown to heavily depend on the pretreatment of the material, as illustrated in detail by the particular case of selective Xylene adsorption. By totally removing the uncoordinated terephthalic acid from the pores and simultaneously avoiding oxidation to nonporous V2O5, pore volume and uptake of Xylenes can be maximized. The presence of uncoordinated terephthalic acid in the pores improves the selectivity between p- and m-Xylene. Calcination bed thickness and oven geometry influence the optimal calcination procedure. The physicochemical modifications of MIL-47 during its activation are investigated in detail with XRD, SEM, nitrogen physisorption, TGA and diffuse reflectance UV-Vis spectroscopy. Using optimally pretreated MIL-47 as adsorbent for Xylene, ethyltoluene, dichlorobenzene, toluidine or cresol isomers, the para-isomer is in each case preferred over the meta-isomer in pulse chromatographic and batch experiments. The role of stacking in the selective adsorption of these isomers is discussed. In the case of the dichlorobenzenes, the meta- and para-isomers can be separated in a breakthrough experiment with a selectivity of 5.0.

Cesar Costapinto Santana - One of the best experts on this subject based on the ideXlab platform.

  • Separation of liquid mixtures of p-Xylene and o-Xylene in X-zeolites: the role of water content on the adsorbent selectivity
    Industrial & Engineering Chemistry Research, 1992
    Co-Authors: L. T. Furlan, Beatriz C. Chaves, Cesar Costapinto Santana
    Abstract:

    The selectivity and purity enhancement related to the separation of the isomers p-Xylene and o-Xylene were studied on a laboratory unit using the liquid-phase adsorption in fixed beds containing zeolite type X whose cation Na + was replaced by Ba 2+ and K + . Using adsorbents with preestablished contents of water and prepared on a special laboratory setup, experiments of the type stimulus-response using the technique of pulses were conducted, being aimed at the determination of the selectivities on the separation of p-Xylene from mixtures with ethylbenzene and also on the separation of p-Xylene from mixture with o-Xylene. It is shown that an optimum water content in X zeolites with a value around 3.25 wt% occurs for the selectivity in separating p-Xylenes and o-Xylenes. We verified that it is possible to obtain with a good yield p-Xylene from a stream of isomers through adsorption in zeolite type X in the liquid phase and that the developed methodology gave precise and repetitive results