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ISRN Physical Chemistry
Volume 2013 (2013), Article ID 164868, 7 pages
http://dx.doi.org/10.1155/2013/164868
Research Article

Acid-Free Nitration of Benzene and Toluene in Zeolite NaZSM-5

Department of Chemistry, East Tennessee State University, P.O. Box 70695, Johnson City, TN 37614, USA

Received 20 December 2012; Accepted 22 January 2013

Academic Editors: F. M. Cabrerizo, B.-T. Liu, X. Rozanska, and E. Yeow

Copyright © 2013 Scott J. Kirkby. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The syntheses of nitrobenzene and p-nitrotoluene directly from benzene, toluene, and NO2 within the pore network of the initially acid-free zeolite NaZSM-5 are reported for the first time. The active species , formed by the interaction of NO2 with the Na+ cations present on the internal surface, results in the acid-free electrophilic substitution of the aromatic ring. There are two distinct reservoirs for the reagents: one associated with close proximity to the cation sites and the other associated with the siliceous areas of the pore network. Up to 34% of the hydrocarbon and 70% of the available NO2 are reacted at 50°C. Only the cation associated sites are reactive at low temperature, and there appears to be little mobility between the sites under the reaction conditions. There is no evidence of a second nitration occurring. This represents a novel route to the single nitration of benzene and toluene and for toluene, the generation of the para isomer exclusively. The pore network of the NaZSM-5 restricts the available reaction volume and transition state geometry allowing only the para-substituted product.