Topics in Catalysis

, Volume 3, Issue 3–4, pp 377–386 | Cite as

Reaction pathway of benzonitrile formation during toluene ammoxidation on vanadium phosphate catalysts

  • A. Martin
  • H. Berndt
  • B. Lücke
  • M. Meisel
Article

Abstract

The reaction pathway of the ammoxidation of toluene on (VO)2P2O7 used as catalyst and the interaction of potential intermediates with the pyrophosphate were studied by spectroscopic techniques (FTIR, EPR), temperature-programmed chemisorptions/ reactions (TPD, TPRS) and transient studies such as the temporal analysis of products (TAP) technique. NH3 is chemisorbed on the catalyst surface, forming three different species, i.e., NH 4 + ions located on BrØnsted sites, coordinatively bound NH3 on Lewis sites and NH 2 groups, presumably P-NH2. Toluene that is probably adsorbed on Lewis sites reacts in a first step to a benzyl radical. A subsequent partial oxidation by interaction of VIV=O groups generates a V...O=CH-C6H5 surface structure. This benzaldehyde-like surface species reacts with adsorbed NH3 according to a Langmuir-Hinshelwood mechanism. TAP experiments on ammonium-containing vanadium phosphates revealed that NH 4 + ions could act as potential N-insertion species. No formation of benzylamine as well as the generation of V=NH surface groups as possible intermediates or N-insertion sites were observed.

Keywords

ammoxidation vanadium phosphate catalysts catalyst/feed interaction reaction mechanism FTIR spectroscopy TAP technique isotope experiments TPD TPRS 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    B.V. Suvorov, Okislitelnyi Ammonoliz Organiceskich Soedinenij (Nauka, Alma-Ata, 1971).Google Scholar
  2. [2]
    F. Cavani and F. Trifirò, La chimica e l'industria 70(4) (1980)58.Google Scholar
  3. [3]
    R.G. Rizayev, E.A. Mamedov, V.P. Vislovskii and V.E. Sheinin, Appl. Catal. A 83(1992)103.Google Scholar
  4. [4]
    A. Andersson, S.L.T. Andersson, G. Centi, R.K. Grasselli, M. Sanati and F. Trifirò, Appl. Catal. A 113(1994)43.Google Scholar
  5. [5]
    G. Centi, ed.,Vanadyl Pyrophosphate Catalysts, Catal. Today 16 (1993).Google Scholar
  6. [6]
    A. Martin, B. Lücke, H. Seeboth and G. Ladwig, Appl. Catal. 49(1989)205.Google Scholar
  7. [7]
    A. Martin, B. Lücke, H. Seeboth, G. Ladwig and E. Fischer, React. Kinet. Catal. Lett. 38(1989)33.Google Scholar
  8. [8]
    Y. Murakami, M. Niwa, T. Hattori, S. Osawa, I. Igushi and H. Ando, J. Catal. 49(1977)83.Google Scholar
  9. [9]
    M. Niwa, H. Ando and Y. Murakami, J. Catal. 49(1977)92.Google Scholar
  10. [10]
    W.S. Chen, H.B. Chiang and M.D. Lee, J. Chin. Inst. Chem. Eng. 25(1) (1994)45.Google Scholar
  11. [11]
    J. Otamiri and A. Andersson, Catal. Today 3(1988)211.Google Scholar
  12. [12]
    J. Otamiri and A. Andersson, Catal. Today 3(1988)223.Google Scholar
  13. [13]
    A.B. Azimov, V.P. Vislovskii, E.A. Mamedov and R.G. Rizayev, J. Catal. 127(1991)354.Google Scholar
  14. [14]
    A. Andersson, J. Catal. 100(1986)414.Google Scholar
  15. [15]
    P. Cavalli, F. Cavani, I. Manenti and F. Trifirò, Ind. Eng. Chem. Res. 26(1987)639.Google Scholar
  16. [16]
    P. Cavalli, F. Cavani, I. Manenti, F. Trifirò and M. El-Sawi, Ind. Eng. Chem. Res. 26(1987)804.Google Scholar
  17. [17]
    G. Busca, F. Cavani and F. Trifirò, J. Catal. 106(1987)471.Google Scholar
  18. [18]
    G. Busca, ACS Symp. Ser. 523(1992)168.Google Scholar
  19. [19]
    L. Forni, M. Toscano and P. Pollesel, J. Catal. 130(1991)392.Google Scholar
  20. [20]
    J.W. Johnson, D.C. Johnston, A.J. Jacobson and J.F. Brody, J. Am. Chem. Soc. 106(1984)8123.Google Scholar
  21. [21]
    E. Bordes, Catal. Today 1(1987)499.Google Scholar
  22. [22]
    A. Martin, B. Lücke, G.U. Wolf and M. Meisel, Catal. Lett. 33(1995)349.Google Scholar
  23. [23]
    Y. Zhang, A. Martin, G.-U. Wolf, S. Rabe, H. Worzala, B. Lücke, M. Meisel and K. Witke, Structural transformations of VOHPO4·1/2H2O in the presence of ammonia, Chem. Mater., submitted.Google Scholar
  24. [24]
    H. Berndt, K. Büker, A. Martin, A. Brückner and B. Lücke, J. Chem. Soc. Faraday. Trans. 91(1995)725.Google Scholar
  25. [25]
    A. Satsuma, Y. Tanaka, A. Hattori, T. Hattori and Y. Murakami, J. Chem. Soc. Chem. Commun. (1994) 1073.Google Scholar
  26. [26]
    A. Satsuma, Y. Tanaka, T. Hattori and Y. Murakami,TOCAT 2 — Second Tokyo Conf. on Advanced Catalytic Science and Technology, Tokyo 1994, Book of Abstracts, Abstr. O-39, p. 185.Google Scholar
  27. [27]
    Y. Zhang, A. Martin, H. Berndt, B. Lücke and M. Meisel, FTIR in-situ investigation on the reaction mechanism of the ammoxidation of toluene on (VO)2P2O7, J. Mol. Catal., in preparation.Google Scholar
  28. [28]
    Y. Zhang, A. Martin, H.W. Zanthoff and M. Meisel, TAP mechanistic study of the ammoxidation of toluene over (VO)2P2O7, Catal. Lett., in preparation.Google Scholar
  29. [29]
    A. Martin, Y. Zhang, H.W. Zanthoff, M. Meisel and M. Baerns, The role of ammonium ions in the mechanism of toluene ammoxidation on VPO catalysts, J. Chem. Soc. Chem. Commun., submitted.Google Scholar

Copyright information

© J.C. Baltzer AG, Science Publishers 1996

Authors and Affiliations

  • A. Martin
    • 1
  • H. Berndt
    • 1
  • B. Lücke
    • 1
  • M. Meisel
    • 2
  1. 1.Institut für Angewandte Chemie Berlin-Adlershof e. V.BerlinGermany
  2. 2.Institut für Anorganische und Allgemeine ChemieHumboldt Universität zu BerlinBerlinGermany

Personalised recommendations