Abstract
H-ZSM-5 zeolite was modified with phosphorus. The obtained P/ZSM-5 catalyst was subjected to further treatments with chromium and nickel. The distribution and strength of different acid sites of zeolites were investigated by means of temperature-programmed desorption of ammonia. The active and strong acid sites were confirmed by measuring the rate constants for cracking ofn-hexane, as a probe molecule. Reduction of pore opening size of the modified ZSM-5 was monitored by a standard test reaction of probe molecules ofm-xylene and ethylbenzene. Selective alkylation of toluene with methanol top-xylene was studied over ZSM-5 and modified zeolite catalysts. The P/ZSM-5 zeolite was the most selective catalyst top-xylene but the toluene conversion decreased drastically. The addition of chromium to P/ZSM-5 zeolite increased the toluene conversion and the yield ofp-xylene was very close to P/ZSM-5 catalyst. The addition of nickel did not exhibit a significant improvement of the catalyst performance. The deactivation of catalysts, due to coke deposition during run, was also considered. P/ZSM-5 zeolite showed the lowest stability with time on stream. The addition of chromium and nickel to P/ZSM-5 zeolite increased the stability of the catalyst.
Similar content being viewed by others
References
J.A. Wei:J. Catal.,76, 433 (1982).
M.A. Uguina, J.L. Sotelo, D.P. Serrano:Ind. Eng. Chem. Res.,31, 1875 (1992).
J.L. Sotelo, M.A. Uguina, J.L. Valverde, D.P. Serrano:Ind. Eng. Chem. Res.,32, 2548 (1993).
W.W. Kaeding, C. Chu, L.B. Young, B. Weinstein, S.A. Butter:J. Catal.,67, 159 (1981).
T. Yashima, Y. Sakaguchi, S. Namba: Proc. 7th International Congress on Catalysis, June 1980,Stud. Surf. Sci. Catal.,7A, 739 (1980).
J. Das, Y.S. Bhat, A.B. Halgeri:Ind. Eng. Chem. Res.,33, 246 (1994).
J. Abbot, F.N. Guerzoni:Appl. Catal.,85, 173 (1992).
S. Faramawy:Petroleum Sci. Technol., (1998), accepted for publication.
G. Bagnasco:J. Catal.,159, 249 (1996).
J. Vedrine, A. Auroux, P. Dejalifve, V. Decarme, H. Hozer, S. Zhou:J. Catal.,115, 291 (1989).
H. Stach, J. Janchen, H. Jerschkewitz, U. Lohse, B. Parlitz:J. Phys. Chem.,96, 8480 (1992).
W.E. Farmeth, R.J. Gorte:Chem Rev.,95, 615 (1995).
D. Bassett, H.W. Habgood:J. Phys. Chem.,64, 769 (1960).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Faramawy, S., El-Sabagh, S.M. & Al-Mehbad, N.Y. Selective alkylation of toluene with methanol overp-modified H-ZSM-5: Effect of treatment with chromium and nickel. React Kinet Catal Lett 66, 257–263 (1999). https://doi.org/10.1007/BF02475799
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02475799