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Benzylation

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Suman K Jana – 1st expert on this subject based on the ideXlab platform

  • Recent developments of heterogeneous solid catalysts for liquid-phase Friedel–Crafts type Benzylation reaction
    Catalysis Surveys from Asia, 2005
    Co-Authors: Suman K Jana

    Abstract:

    Liquid-phase Friedel–Crafts type Benzylation of aromatics has been effected traditionally with catalysis by homogeneous protonic acid or Lewis acid. However, heterogeneous catalysts have the advantages, compared to their homogeneous counterparts, of facile recovering and recycling. This short article describes the recent advances in the liquid-phase Friedel–Crafts type Benzylation by benzyl chloride of aromatics over redox metal: gallium (Ga), indium (In) and thallium (Tl) containing novel heterogeneous solid catalysts. Unlike conventional acidic catalyst, the Benzylation activity of the Ga-, In- or Tl-based solids does not depend solely on their acidic properties, even present; these solids in their non-acidic or basic form also shows high Benzylation activity. The catalytic activity order of Ga, In and Tl containing solid catalysts supported on chemically similar inert catalyst carrier is as follows: thallium/support > indium/support > gallium/support, which is quite similar to their redox potential values indicating the role of redox function in the Benzylation process. A plausible reaction mechanism for the Benzylation reaction over these catalysts is proposed. These heterogeneous solids are highly efficient for the Friedel–Crafts type Benzylation, even in the presence of moisture, than the conventional strongly acidic solid acid catalysts.

  • Benzylation of benzene by benzyl chloride over fe modified zsm 5 and h β zeolites and fe2o3 or fecl3 deposited on micro meso and macro porous supports
    Microporous and Mesoporous Materials, 2002
    Co-Authors: Vasant R Choudhary, Suman K Jana, Ajit S Mamman

    Abstract:

    Abstract A number of Fe-containing solid catalysts, such as Fe-modified ZSM-5 type zeolites (Fe 2 O 3 /H-ZSM-5, SO 4 2− /Fe 2 O 3 /H-ZSM-5, H-FeMFI and H-FeAlMFI), Fe-modified H-β zeolites (Fe 2 O 3 /H-β and SO 4 2− /Fe 2 O 3 /H-β), Fe 2 O 3 supported on meso-porous Si-MCM-41, silica gel or macro-porous silica–alumina commercial catalyst carrier (SA-5205), and FeCl 3 impregnated on 13X zeolite, Si-MCM-41, silica gel or commercial clays––montmorillonite K10 (Mont K10) or kaolin, have been compared for their performance in the Benzylation of benzene by benzyl chloride (80 °C). Among these catalysts, the Fe 2 O 3 /H-β (or H-ZSM-5) and FeCl 3 /Mont K10 (or Si-MCM-41) are found to be highly promising ones for the Benzylation, even in the presence of moisture. These catalysts can also be reused in the reaction but with reduced activity. No direct relationship is observed between the acidity (measured in terms of ammonia chemisorbed at 50 or 200 °C) and the Benzylation activity of the catalysts. The Benzylation activity is controlled mainly by the redox properties of the catalyst. The selectivity for diphenyl methane in the Benzylation was found to vary from catalyst to catalyst.

  • Benzylation of benzene and substituted benzenes by benzyl chloride over incl3 gacl3 fecl3 and zncl2 supported on clays and si mcm 41
    Journal of Molecular Catalysis A-chemical, 2002
    Co-Authors: Vasant R Choudhary, Suman K Jana

    Abstract:

    Abstract Liquid phase Benzylation of benzene by benzyl chloride to diphenyl methane over InCl3, GaCl3, FeCl3 and ZnCl2 supported on commercial clays (viz. Montmorillonite-K10, Montmorillonite-KSF and Kaolin) or on high silica mesoporous MCM-41 (at 60, 70 and 80 °C) has been investigated. The supported InCl3, GaCl3 and FeCl3 showed high activity for the Benzylation of benzene. The redox function created due to the impregnation of the clays or Si-MCM-41 by InCl3, GaCl3, FeCl3 or ZnCl2 seems to play a very important role in the Benzylation process. Among the catalysts, the InCl3/Mont.-K10 showed both high activity and high selectivity for the Benzylation. The activity of this catalyst for the Benzylation of different aromatic compounds is in the following order: benzene>toluene>mesitylene>anisole. The InCl3 (or GaCl3)/Mont.-K10 (or Si-MCM-41) catalyst showed high benzene Benzylation activity even in the presence of moisture in the reaction mixture. The catalyst can also be reused in the Benzylation for several times. Kinetics of the benzene Benzylation (using excess of benzene) over the supported metal chloride catalysts have also been thoroughly investigated. A plausible reaction mechanism for the Benzylation over the supported metal chloride catalysts is proposed.

Vasant R Choudhary – 2nd expert on this subject based on the ideXlab platform

  • Highly active and reusable catalyst from Fe-Mg-hydrotalcite anionic clay for Friedel-Crafts type Benzylation reactions
    Journal of Chemical Sciences, 2005
    Co-Authors: Vasant R Choudhary, Pankaj A. Choudhari

    Abstract:

    Fe-Mg-hydrotalcite (Mg/Fe = 3) anionic clay with or without calcination (at 200–800‡C) has been used for the Benzylation of toluene and other aromatic compounds by benzyl chloride. Hydrotalcite before and after its calcination was characterized for surface area, crystalline phases and basicity. Both the hydrotalcite, particularly after its use in the Benzylation reaction, and the catalyst derived from it by its calcination at 200–800‡C show high catalytic activity for the Benzylation of toluene and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the chlorides and oxides of iron on the catalyst surface.

  • Benzylation of benzene by benzyl chloride over fe modified zsm 5 and h β zeolites and fe2o3 or fecl3 deposited on micro meso and macro porous supports
    Microporous and Mesoporous Materials, 2002
    Co-Authors: Vasant R Choudhary, Suman K Jana, Ajit S Mamman

    Abstract:

    Abstract A number of Fe-containing solid catalysts, such as Fe-modified ZSM-5 type zeolites (Fe 2 O 3 /H-ZSM-5, SO 4 2− /Fe 2 O 3 /H-ZSM-5, H-FeMFI and H-FeAlMFI), Fe-modified H-β zeolites (Fe 2 O 3 /H-β and SO 4 2− /Fe 2 O 3 /H-β), Fe 2 O 3 supported on meso-porous Si-MCM-41, silica gel or macro-porous silica–alumina commercial catalyst carrier (SA-5205), and FeCl 3 impregnated on 13X zeolite, Si-MCM-41, silica gel or commercial clays––montmorillonite K10 (Mont K10) or kaolin, have been compared for their performance in the Benzylation of benzene by benzyl chloride (80 °C). Among these catalysts, the Fe 2 O 3 /H-β (or H-ZSM-5) and FeCl 3 /Mont K10 (or Si-MCM-41) are found to be highly promising ones for the Benzylation, even in the presence of moisture. These catalysts can also be reused in the reaction but with reduced activity. No direct relationship is observed between the acidity (measured in terms of ammonia chemisorbed at 50 or 200 °C) and the Benzylation activity of the catalysts. The Benzylation activity is controlled mainly by the redox properties of the catalyst. The selectivity for diphenyl methane in the Benzylation was found to vary from catalyst to catalyst.

  • Benzylation of benzene and substituted benzenes by benzyl chloride over incl3 gacl3 fecl3 and zncl2 supported on clays and si mcm 41
    Journal of Molecular Catalysis A-chemical, 2002
    Co-Authors: Vasant R Choudhary, Suman K Jana

    Abstract:

    Abstract Liquid phase Benzylation of benzene by benzyl chloride to diphenyl methane over InCl3, GaCl3, FeCl3 and ZnCl2 supported on commercial clays (viz. Montmorillonite-K10, Montmorillonite-KSF and Kaolin) or on high silica mesoporous MCM-41 (at 60, 70 and 80 °C) has been investigated. The supported InCl3, GaCl3 and FeCl3 showed high activity for the Benzylation of benzene. The redox function created due to the impregnation of the clays or Si-MCM-41 by InCl3, GaCl3, FeCl3 or ZnCl2 seems to play a very important role in the Benzylation process. Among the catalysts, the InCl3/Mont.-K10 showed both high activity and high selectivity for the Benzylation. The activity of this catalyst for the Benzylation of different aromatic compounds is in the following order: benzene>toluene>mesitylene>anisole. The InCl3 (or GaCl3)/Mont.-K10 (or Si-MCM-41) catalyst showed high benzene Benzylation activity even in the presence of moisture in the reaction mixture. The catalyst can also be reused in the Benzylation for several times. Kinetics of the benzene Benzylation (using excess of benzene) over the supported metal chloride catalysts have also been thoroughly investigated. A plausible reaction mechanism for the Benzylation over the supported metal chloride catalysts is proposed.

O Cherifi – 3rd expert on this subject based on the ideXlab platform

  • Catalytic properties of the Cr-HMS materials in the Benzylation of benzene with benzyl chloride
    Kinetics and Catalysis, 2011
    Co-Authors: Khaldoun Bachari, A. Touileb, N. Tahir, Adel Saadi, D. Halliche, O Cherifi

    Abstract:

    A series of chromium-containing mesoporous silicas with different Cr contents were prepared and characterized with chemical analysis, N2 adsorption measurements (BET equation and BJH theory), X-ray diffraction, diffuse reflectance UV-visible and H2-temperature programmed reduction techniques. Excellent results in Benzylation of benzene and substituted benzenes employing benzyl chloride as the alkylating agent were obtained. The mesoporous chromium-containing materials showed both high activity and high selectivity for Benzylation of benzene. The activity of these catalysts for the Benzylation of different aromatic compounds is in the following order: benzene > toluene > p-xylene > anisole. Kinetics of the benzene Benzylation over these catalysts has also been investigated.

  • Catalytic properties of antimony-SBA-15 materials in the Benzylation of aromatics reactions
    Kinetics and Catalysis, 2009
    Co-Authors: Khaldoun Bachari, A. Touileb, O Cherifi

    Abstract:

    Antimony-containing mesoporous SBA-15 with different Si/Sb ratio has been synthesized using a post-treatment procedure with an aqueous solution of SbCl3 and characterized by elemental analysis, XRD method, N2 adsorption measurements (BET and BJH theory) and FTIR spectroscopy. The Benzylation of aromatics by benzyl chloride has been investigated over these solids. Indeed, the antimony-containing mesoporous SBA-15 showed both high activity and high selectivity for this reaction. More interesting is the observation that Sb-SBA-15 (35) catalyst is active and selective for large molecules like naphthenic compounds such as 2-methylnaphthalene and it can also be reused in the Benzylation of benzene for several times. Kinetics of the benzene Benzylation over these catalysts have also been investigated.

  • Study of the Benzylation of aromatics over Mg-Cr-hydrotalcite catalysts
    Studies in Surface Science and Catalysis, 2008
    Co-Authors: Nadia Tahir, O Cherifi, Adel Saadi, D. Halliche, Z Abdelssadek, Khaldoun Bachari

    Abstract:

    Abstract The Benzylation of aromatics by benzyl chloride over Mg-Cr-LDH (Mg/Cr = 2) clay without or with calcination (at 473–1073K) has been investigated. The catalyst derived from the hydrotalcite by its calcination at 473–1073K show high catalytic activity for the Benzylation of aromatics. The catalytically active species present in the catalyst in its most active form are the oxides of chromium on the catalyst surface. The activity of the catalyst calcined at 1073K for the Benzylation of different aromatic compounds is in the following order: benzene > toluene > p -xylene > anisole.