Hydroxylation Mechanism of Aromatics

  • Author: Theresa Kueckmann
  • Published Date: 07 November 2016
  • Source / Publisher: Chemistry – An Asian Journal/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
thumbnail image: Hydroxylation Mechanism of Aromatics

The hydroxylation of weakly polar aromatics into water-soluble phenols can be performed by advanced oxidation technologies such as aqueous TiO2 photocatalysis and the Fenton reaction. In many cases, this is the only route for the degradation of these insoluble aromatic pollutants in water. However, the mechanism by which the hydroxyl group finally attaches to the benzene ring has remained tricky.

Jincai Zhao and Wanhong Ma, Chinese Academy of Sciences, Beijing, used deuterium-labeled toluene and p-xylene as model substrates to observe the replacement of ipso-2H and CH3 by OH groups by aqueous TiO2 photocatalysis and the Fenton reaction.

The team found found that in the hydroxylation products, a certain proportion of 2H and CH3 groups was not replaced by OH groups as expected in the previously proposed O2-insertion mechanism. Instead, they were shifted to the adjacent carbon position of the ring (called a 1,2-NIH shift effect).

The results indicate that there is more than one mechanism to attach the OH group of H2O or H2O2 onto the benzene ring.


Article Views: 3817

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission and consult our permission guidance prior to making your request

Follow on Facebook Follow on Twitter Follow on YouTube Follow on LinkedIn Follow on Instagram RSS Sign up for newsletters

Magazine of Chemistry Europe (16 European Chemical Societies) published by Wiley-VCH