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
|
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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