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Regioselective nitration of deactivated mono-substituted benzenes using acyl nitrates over reusable acidic zeolite catalysts

Smith, Keith, Ajarim, Mansour Dahish and El-Hiti, Gamal A. 2010. Regioselective nitration of deactivated mono-substituted benzenes using acyl nitrates over reusable acidic zeolite catalysts. Catalysis Letters 134 (3-4) , pp. 270-278. 10.1007/s10562-009-0258-7

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Abstract

Nitration of benzonitrile was investigated using a nitric acid/acid anhydride/zeolite catalyst system under different reaction conditions. Trifluoroacetic and chloroacetic anhydrides were found to be the most active among the anhydrides tried. Also, zeolites Hβ and Fe3+β (Si/Al = 12.5) were found to be the most active catalysts. For example, nitration of benzonitrile with trifluoroacetyl nitrate under reflux conditions in dichloromethane gave 3- and 4-nitrobenzonitriles in quantitative yield, of which the para-isomer represented 24–28%. The yield of para-isomer was improved to 33% when passivated Hβ was used under similar reaction conditions. This is easily the most para-selective nitration of benzonitrile ever recorded. Also, no ortho-isomer was formed under the conditions tried. The zeolite can be easily recovered, regenerated by heating and reused up to six times to give results similar to those obtained with a fresh sample of the catalyst. The nitration system was applied successfully to a range of deactivated mono-substituted benzenes to give para-isomers in significantly higher proportions than in the corresponding traditional nitration reactions.

Item Type: Article
Status: Published
Schools: Chemistry
Subjects: Q Science > QD Chemistry
Uncontrolled Keywords: Nitration; Deactivated mono-substituted benzenes; Acyl nitrate; Acidic zeolite catalysis; Hβ; Regioselectivity
Publisher: Springer Verlag
ISSN: 1011-372X
Date of First Compliant Deposit: 30 March 2016
Last Modified: 04 Feb 2018 01:17
URI: http://orca.cf.ac.uk/id/eprint/12722

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