Effect of alkali metals added to Cu ion-exchanged Y-type zeolite catalysts in the gas-phase catalytic oxidation of benzyl alcohol

Abstract

The effect of alkali metals added to Cu ion-exchanged Y-type (Cu-NaY) zeolite catalysts on the oxidation activity and the selectivity is investigated using the gas-phase catalytic oxidation of benzyl alcohol as a model reaction. The added alkali metals such as K have been found to promote significantly the catalytic oxidation activity of the Cu-NaY catalysts. In particular, the addition of alkali metals to the Cu-NaY zeolites caused an increase in the yield of the partial oxidation product, benzaldehyde. Thus, the alkali metals added to the Cu-NaY zeolites were found to increase the selectivity of the partial oxidation of benzyl alcohol. The influences of the percentage of Cu ion-exchange, the type of added alkali metal, the amount of the added alkali metal and the atomic ratio of added alkali metal/Cu on the oxidation activity and/or the selectivity of the partial oxidation product are investigated in detail. The absence of gaseous oxygen molecules leads to no deep oxidation products (carbon oxides, CO₂+CO). On the other hand, benzaldehyde, the partial oxygen product, is produced, though the yield is lower and decreases with time-on-stream, even after halting the oxygen supply following steady state benzyl alcohol oxidation. The yield of benzaldehyde in the absence of oxygen catalyzed by alkali metal added Cu-NaY is found to be considerably higher than that catalyzed by Cu-NaY without added alkali metal. The amount of oxygen uptake of the prereduced alkali metal added Cu-NaY zeolite is found to be higher than that of the prereduced Cu-NaY without added alkali metal. One of the roles of the alkali metal added to the Cu-NaY zeolites is to increase the adsorbed oxygen species, which plays an important role in the partial oxidation of benzyl alcohol to benzaldehyde.

References

1. Y. Ben Taarit and M. Che, in Catalysis by Zeolites, ed. C. Naccache, Y. Ben Taarit, J. C. Vedrine, G. Coudurier and H. Praliaud, Elsevier, Amsterdam, 1980, p. 167.
2. C. Naccache and Y. Ben Taarit, in Zeolites: Science and Technology, ed. F. R. Ribeiro, A. E. Rodrigues, L. D. Rollmann and C. Naccache, Martinus Nijhoff, The Hague, 1984, p. 379.
3. M. Iwamoto, M. Yokoo, K. Sakai and S. Kagawa, J. Chem. Soc., Faraday Trans. 1, 1981, 77, 1629.
4. M. Iwamoto, H. Yahiro, K. Tanda, Y. Mizuno, Y. Mine and S. Kagawa, J. Phys. Chem., 1991, 95, 3727.
5. Y. Li and W. K. Hall, J. Catal., 1991, 129, 202.
6. J. L. d'Itri and W. M. H. Sachtler, Catal. Lett., 1992, 15, 289.
7. J. O. Petunchi, G. A. Sill and W. K. Hall, Appl. Catal. B., 1993, 2, 303.
8. B. Coq, D. Tachon, F. Figueras, G. Mabilon and M. Prigent, Appl. Catal. B: Environ., 1995, 6, 271.
9. G. Centi and S. Perathoner, Appl. Catal. A: Gen., 1995, 132, 179.
10. T. Cheung, S. K. Bhargava, H. Hobday and K. Foger, J. Catal., 1996, 158, 301.
11. T. Beutel, B. Adelman and W. M. H. Sachtler, Catal. Lett., 1996, 37, 125.
12. C. Torreabreu, M. F. Ribeiro, C. Henriques and F. R. Ribeiro, Catal. Lett., 1997, 43, 25.
13. D. C. Sayle, C. R. A. Catlow, J. D. Gale, M. A. Perrin and P. Nortier, J. Phys. Chem., 1997, 101, 3331.
14. T. Ishihara, M. Kagawa, F. Hadama and Y. Takita, J. Catal., 1997, 169, 93.
15. J. H. Lunsford, Catal. Rev., 1975–1976, 12, 137.
16. R. F. Howe and J. H. Lunsford, J. Am. Chem. Soc., 1975, 97, 5156.
17. R. F. Howe and J. H. Lunsford, J. Phys. Chem., 1975, 79, 1836.
18. H. Miyazaki, S. Nishiyama, S. Tsuruya and M. Masai, Proceedings of 9th International Congress on Catalysis, ed. M. J. Phillips and M. Ternan, Chemical Institute of Canada, Ottawa, 1988, p. 491.
19. L. I. Simandi, Catalytic Activation of Dioxygen by Metal Complexes (Catalysis by Metal Complexes, vol. 13), Kluwer Academic, Dordrecht, 1992.
20. S. Tsuruya, Trends Inorg. Chem., 1993, 3, 71.
21. S. Tsuruya, K. Nakamae and T. Yonezawa, J. Catal., 1976, 44, 40.
22. S. Tsuruya, T. Takaki and M. Masai, J. Catal., 1984, 89, 511.
23. T. Takaki, S. Nishiyama, S. Tsuruya and M. Masai, Proceedings of World Congress III of Chemical Engineering, The Society of Chemical Engineers, Japan, Tokyo, 1986, vol. IV, p. 330.
24. H. Hayashibara, T. Nanbu, S. Nishiyama, S. Tsuruya and M. Masai, in Proceedings of 9th International Zeolites Conference, Montreal, ed. R. von Ballmoos, J. B. Higgins and M. M. J. Treaty, Butterworth–Heinemann, London, 1993, p. 575.
25. Hayashibara, S. Nishiyama, S. Tsuruya and M. Masai, J. Catal., 1995, 153, 254.
26. M. Genta, S. Nishiyama, S. Tsuruya and M. Masai, J. Chem. Soc., Faraday Trans., 1996, 92, 1267.
27. S. Bun, S. Nishiyama, S. Tsuruya and M. Masai, Appl. Catal., 1990, 59, 13.