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Suman K Jana - One of the best experts on this subject based on the ideXlab platform.

  • friedel crafts type benzylation and Benzoylation of aromatic compounds over hβ zeolite modified by oxides or chlorides of gallium and indium
    Microporous and Mesoporous Materials, 2003
    Co-Authors: Vasant R. Choudhary, Suman K Jana, Nilesh Sudhir Patil, Suresh K Bhargava
    Abstract:

    Liquid phase benzylation (by benzyl chloride) and Benzoylation (by benzoyl chloride) of benzene and other aromatic compounds over different Ga- and In-modified Hb zeolite catalysts at 80 � C have been investigated. An impregnation of the zeolite by oxides or chlorides of Ga and In makes the zeolite highly active in the benzylation process but it results in a decrease in the acidity, particularly the strong acid sites (measured in terms of the ammonia chemisorbed at 250 � C) of the zeolite. Both the redox function, created due to the modification of the Hb zeolite by Ga or In, and the zeolitic acidity seem to play important role in the benzylation or Benzoylation process. Among the different Ga- and In-modified Hb zeolite catalysts, the In2O3/Hb showed highest activity for the benzene benzylation. This catalyst also showed high activity for both the benzylation and Benzoylation of other aromatic compounds, even in the presence of moisture in the reaction mixture; in case of the Benzoylation, the moisture has beneficial effect. The In2O3/Hb catalyst can be reused in the benzylation for several times. Kinetics of benzene benzylation (using excess of benzene) over the different Ga- and Inmodified Hb zeolite catalysts has also been investigated. A plausible mechanism for the activation of both the reactants (aromatic substrate and benzyl or benzoyl chloride, forming corresponding carbocation) over the catalyst and also for the reaction between the carbocation and the activated and/or non-activated aromatic substrate is proposed. � 2002 Elsevier Science Inc. All rights reserved.

  • 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.

  • Benzoylation of benzene and substituted benzenes by benzoyl chloride over in2o3 si mcm 41 catalyst
    Journal of Molecular Catalysis A-chemical, 2002
    Co-Authors: Vasant R. Choudhary, Suman K Jana
    Abstract:

    Abstract Liquid phase Benzoylation of benzene by benzoyl chloride over In 2 O 3 , Ga 2 O 3 and ZnO supported on high silica mesoporous MCM-41 at 80 °C has been investigated. The supported In 2 O 3 , Ga 2 O 3 and ZnO catalysts showed high activity for the Benzoylation of benzene. The redox function and activation of aromatic substrate by the supported basic In 2 O 3 and amphoteric Ga 2 O 3 or ZnO seem to play a very important role in the Benzoylation process. Among the catalysts, the In 2 O 3 /Si-MCM-41 showed the highest activity for the Benzoylation of benzene. The activity of this catalyst for the Benzoylation of benzene and substituted benzenes is in the following order: anisole>mesitylene> p -xylene>toluene>benzene. The In 2 O 3 (or Ga 2 O 3 )/Si-MCM-41 showed high Benzoylation activity of benzene even in the presence of appreciable amounts of moisture in the reaction mixture. Solvent and its nature (polar or non-polar) also play important role in the Benzoylation over the supported In 2 O 3 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.

  • benzylation of benzene by benzyl chloride over fe zn ga and in modified zsm 5 type zeolite catalysts
    Applied Catalysis A-general, 2002
    Co-Authors: Vasant R. Choudhary, Suman K Jana
    Abstract:

    Liquid phase benzylation of benzene by benzyl chloride to diphenylmethane over H-ZSM-5, H-gallosilicate (MFI), H-galloaluminosilicate (MFI), H-ferrosilicate (MFI), H-ferroaluminosilicate (MFI), Fe 2 O 3 /H-ZSM-5, ZnO/H-ZSM-5, Ga 2 O 3 /H-ZSM-5 and In 2 O 3 /H-ZSM-5 zeolites (at 60 and 80°C) has been investigated. A complete or partial substitution of Al in H-ZSM-5 zeolite by Fe or Ga or an impregnation of the zeolite by Fe 2 O 3 , ZnO, Ga 2 O 3 or In 2 O 3 makes the zeolite highly active in the benzylation process. The redox function created due to the modification of the H-ZSM-5 zeolite by Fe, Zn, Ga or In seems to play very important role in the benzylation process. However, all these catalysts show a significant induction period for the reaction. The Ga 2 O 3 /H-ZSM-5 catalyst showed high benzene benzylation activity even in the presence of moisture in the catalyst and/or in the substrate. However, the reaction induction period is increased markedly with increasing the moisture and it is reduced by removing the moisture from the catalyst by refluxing with moisture-free benzene. It is also reduced by the HCl gas pretreatment to the catalyst before the benzylation reaction. The Ga 2 O 3 /H-ZSM-5 and In 2 O 3 /H-ZSM-5 catalysts showed excellent reusability in the benzene benzylation. Kinetics of the benzene benzylation (using an excess of benzene) over the H-GaMFI, H-GaAlMFI, H-FeMFI, Ga 2 O 3 /H-ZSM-5 and In 2 O 3 /H-ZSM-5 catalysts have also been thoroughly investigated. A plausible reaction mechanism for the reaction over the modified ZSM-5 zeolite catalysts is proposed.

Vasant R. Choudhary - One of the best experts on this subject based on the ideXlab platform.

  • friedel crafts type benzylation and Benzoylation of aromatic compounds over hβ zeolite modified by oxides or chlorides of gallium and indium
    Microporous and Mesoporous Materials, 2003
    Co-Authors: Vasant R. Choudhary, Suman K Jana, Nilesh Sudhir Patil, Suresh K Bhargava
    Abstract:

    Liquid phase benzylation (by benzyl chloride) and Benzoylation (by benzoyl chloride) of benzene and other aromatic compounds over different Ga- and In-modified Hb zeolite catalysts at 80 � C have been investigated. An impregnation of the zeolite by oxides or chlorides of Ga and In makes the zeolite highly active in the benzylation process but it results in a decrease in the acidity, particularly the strong acid sites (measured in terms of the ammonia chemisorbed at 250 � C) of the zeolite. Both the redox function, created due to the modification of the Hb zeolite by Ga or In, and the zeolitic acidity seem to play important role in the benzylation or Benzoylation process. Among the different Ga- and In-modified Hb zeolite catalysts, the In2O3/Hb showed highest activity for the benzene benzylation. This catalyst also showed high activity for both the benzylation and Benzoylation of other aromatic compounds, even in the presence of moisture in the reaction mixture; in case of the Benzoylation, the moisture has beneficial effect. The In2O3/Hb catalyst can be reused in the benzylation for several times. Kinetics of benzene benzylation (using excess of benzene) over the different Ga- and Inmodified Hb zeolite catalysts has also been investigated. A plausible mechanism for the activation of both the reactants (aromatic substrate and benzyl or benzoyl chloride, forming corresponding carbocation) over the catalyst and also for the reaction between the carbocation and the activated and/or non-activated aromatic substrate is proposed. � 2002 Elsevier Science Inc. All rights reserved.

  • 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.

  • Benzoylation of benzene and substituted benzenes by benzoyl chloride over in2o3 si mcm 41 catalyst
    Journal of Molecular Catalysis A-chemical, 2002
    Co-Authors: Vasant R. Choudhary, Suman K Jana
    Abstract:

    Abstract Liquid phase Benzoylation of benzene by benzoyl chloride over In 2 O 3 , Ga 2 O 3 and ZnO supported on high silica mesoporous MCM-41 at 80 °C has been investigated. The supported In 2 O 3 , Ga 2 O 3 and ZnO catalysts showed high activity for the Benzoylation of benzene. The redox function and activation of aromatic substrate by the supported basic In 2 O 3 and amphoteric Ga 2 O 3 or ZnO seem to play a very important role in the Benzoylation process. Among the catalysts, the In 2 O 3 /Si-MCM-41 showed the highest activity for the Benzoylation of benzene. The activity of this catalyst for the Benzoylation of benzene and substituted benzenes is in the following order: anisole>mesitylene> p -xylene>toluene>benzene. The In 2 O 3 (or Ga 2 O 3 )/Si-MCM-41 showed high Benzoylation activity of benzene even in the presence of appreciable amounts of moisture in the reaction mixture. Solvent and its nature (polar or non-polar) also play important role in the Benzoylation over the supported In 2 O 3 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.

  • benzylation of benzene by benzyl chloride over fe zn ga and in modified zsm 5 type zeolite catalysts
    Applied Catalysis A-general, 2002
    Co-Authors: Vasant R. Choudhary, Suman K Jana
    Abstract:

    Liquid phase benzylation of benzene by benzyl chloride to diphenylmethane over H-ZSM-5, H-gallosilicate (MFI), H-galloaluminosilicate (MFI), H-ferrosilicate (MFI), H-ferroaluminosilicate (MFI), Fe 2 O 3 /H-ZSM-5, ZnO/H-ZSM-5, Ga 2 O 3 /H-ZSM-5 and In 2 O 3 /H-ZSM-5 zeolites (at 60 and 80°C) has been investigated. A complete or partial substitution of Al in H-ZSM-5 zeolite by Fe or Ga or an impregnation of the zeolite by Fe 2 O 3 , ZnO, Ga 2 O 3 or In 2 O 3 makes the zeolite highly active in the benzylation process. The redox function created due to the modification of the H-ZSM-5 zeolite by Fe, Zn, Ga or In seems to play very important role in the benzylation process. However, all these catalysts show a significant induction period for the reaction. The Ga 2 O 3 /H-ZSM-5 catalyst showed high benzene benzylation activity even in the presence of moisture in the catalyst and/or in the substrate. However, the reaction induction period is increased markedly with increasing the moisture and it is reduced by removing the moisture from the catalyst by refluxing with moisture-free benzene. It is also reduced by the HCl gas pretreatment to the catalyst before the benzylation reaction. The Ga 2 O 3 /H-ZSM-5 and In 2 O 3 /H-ZSM-5 catalysts showed excellent reusability in the benzene benzylation. Kinetics of the benzene benzylation (using an excess of benzene) over the H-GaMFI, H-GaAlMFI, H-FeMFI, Ga 2 O 3 /H-ZSM-5 and In 2 O 3 /H-ZSM-5 catalysts have also been thoroughly investigated. A plausible reaction mechanism for the reaction over the modified ZSM-5 zeolite catalysts is proposed.

Isao Azumaya - One of the best experts on this subject based on the ideXlab platform.

Hidemasa Hikawa - One of the best experts on this subject based on the ideXlab platform.

Hideharu Suzuki - One of the best experts on this subject based on the ideXlab platform.