Catalysis Letters

, Volume 26, Issue 1–2, pp 159–167 | Cite as

Continuous flow toluene methylation over AlPO4 and AlPO4-Al2O3 catalysts

  • F. M. Bautista
  • A. Blanco
  • J. M. Campelo
  • A. Garcia
  • D. Luna
  • J. M. Marinas
  • A. A. Romero
Article

Abstract

Toluene methylation with methanol over AlPO4 (AP) and AlPO4-Al2O3 (APAl) catalysts, obtained through different methods, was carried out in a continuous down-flow fixed bed reactor. The main products were xylenes (XYL), although trimethylbenzenes (TMB) were also found over APAl catalysts. The benzene and ethylbenzene selectivities increased slightly with time on stream at the expense of XYL and TMB selectivities. Isomer distribution was approximately 50, 24 and 26 mol% foro-, m- andp-XYL, and 72, 27 and 0 mol% for 1,2,3-, 1,2,4- and 1,3,5-TMB. The initial reaction rate constants were higher on APA1 catalysts and, furthermore, APAl catalysts exhibited similar catalytic activities, although those obtained in ethylene or propylene oxide are the most active ones. The same occurs on AP catalysts. Moreover, the changes in catalytic activity are similar to the changes in the acidic characteristics measured, in gas phase, versus pyridine. Furthermore, the activity decreased with time on stream due to coke deposition according to the expressionk = k0 exp(-βt). The rate of deactivation, evaluated from the deactivation coefficients (β), was greater for APAl than for AP catalysts.

Keywords

aluminum orthophosphate (AlPO4AlPO4-Al2O3 toluene methylation methanol activity selectivity 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    F.G. Dwyer, in:Catalysis in Organic Reactions, Vol. 5, ed. W.R. Moser (Dekker, New York, 1981) p. 39.Google Scholar
  2. [2]
    W.W. Kaeding, C. Chu, L.B. Young, B. Weinstein and S.A. Butter, J. Catal. 67 (1981) 159.Google Scholar
  3. [3]
    W.W. Kaeding, L.B. Young and C. Chu, J. Catal. 89 (1984) 267.Google Scholar
  4. [4]
    P.B. Venuto, in:Molecular Sieve Zeolites II, Adv. Chem. Ser. 102 (1971) 260.Google Scholar
  5. [5]
    B. Coughlan, W.M. Carroll and J. Nunan, J. Chem. Soc. Faraday Trans. I 79 (1983) 281.Google Scholar
  6. [6]
    W.F. Hölderich, M. Hesse and F. Näumann, Angew. Chem. Int. Ed. 27 (1988) 226.Google Scholar
  7. [7]
    A. Blanco, J.M. Campelo, A. Garcia, D. Luna, J.M. Marinas and A.A. Romero, J. Catal. 137 (1992) 51.Google Scholar
  8. [8]
    J.M. Campelo, J.M. Marinas, S. Mendioroz and J. Pajares, J. Catal. 101 (1986) 484.Google Scholar
  9. [9]
    J.M. Campelo, A. Garcia, D. Luna, J.M. Marinas and M.I. Martinez, Mater. Chem. Phys. 21 (1989) 409.Google Scholar
  10. [10]
    L.B. Young, S.A. Butter and W.W. Kaeding, J. Catal. 76 (1982) 418.Google Scholar
  11. [11]
    D.H. Olson and W.O. Haag, ACS Symp. Ser. 248 (1984) 275.Google Scholar
  12. [12]
    H. Vinek and J.A. Lercher, J. Mol. Catal. 64 (1991) 23.Google Scholar
  13. [13]
    D. Bethell and V. Gold, in:Carbonium Ions — An Introduction (Academic Press, London, 1967) p. 178.Google Scholar
  14. [14]
    T. Yashima, H. Ahmad, K. Yamazaki, M. Katsuta and N. Hara, J. Catal. 16 (1970) 273.Google Scholar
  15. [15]
    T. Yashima, H. Ahmad, K. Yamazaki, M. Katsuta and N. Hara, J. Catal. 17 (1970) 151.Google Scholar
  16. [16]
    A.N. Ko and B.W. Wojciechowski, Prog. React. Kinet. 12 (1983) 201.Google Scholar

Copyright information

© J.C. Baltzer AG, Science Publishers 1994

Authors and Affiliations

  • F. M. Bautista
    • 1
  • A. Blanco
    • 1
  • J. M. Campelo
    • 1
  • A. Garcia
    • 1
  • D. Luna
    • 1
  • J. M. Marinas
    • 1
  • A. A. Romero
    • 1
  1. 1.Department of Organic ChemistryCordoba UniversityCordobaSpain

Personalised recommendations