INOR 871 |
| The nitration of aromatic compounds is important for the industrial production of fine chemical precursors. The most promising acid catalysts for these reactions include zeolites, which allow for high regiospecificity. We have examined the nitration of toluene in a mixture of nitric acid and acetic anhydride. The yields and product selectivities of the homogeneous solutions will be compared to the results of heterogeneous solutions using zeolite beta (SiO2/Al2O3 ratio = 25 and 50), mordenite (Si/Al = 20), faujasite (Y, Si/Al = 12) and ZSM-5 (Si/Al = 23). Significant differences in product yield and selectivities were attained depending on the zeolite, Si/Al ratio, and zeolite cation (NH4+, Na+, Fe2+ or Mg2+). The effects of reaction temperature and zeolite hydration will also be demonstrated. Previously an enhanced para-selectivity was noted with zeolite beta and the superior performance was attributed to the reaction of the arene with a surface bound acetyl nitrate complex and/or the reversible transformation of framework aluminum from a tetrahedral into an octahedral environment; these mechanisms will be considered in light of the available data.
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Inorganic Catalysts
8:30 AM-11:50 AM, Wednesday, 13 September 2006 Moscone Center -- Room 302, Oral
Division of Inorganic Chemistry |