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Water as a catalytic switch in the oxidation of aryl alcohols by polymer incarcerated rhodium nanoparticles

Lookup NU author(s): Dr Mariela Bravo Sanchez, Dr Naoko Sano, Professor Peter Cumpson

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This is the authors' accepted manuscript of an article that has been published in its final definitive form by Royal Society of Chemistry, 2017.

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Abstract

One of the major goals in the oxidation of organic substrates, and especially for alcohol oxidation, is the use of molecular oxygen as the oxidant under mild conditions. Here we report the synthesis and testing of Rh polymer incarcerated catalysts, using a metal so far not used for alcohol oxidation reactions, in which the catalytic activity towards aryl alcohol oxidation, for substrates like 1-phenylethanol and benzyl alcohol, is switched on by the addition of water as co-solvent in toluene. This is done by using air as oxidant at atmospheric pressure, in one of the mildest reaction conditions reported for this class of reaction. The promoting effect of water to higher conversions was observed also for rhodium over alumina supported catalysts, which were used as a benchmark allowing in all cases high conversion and selectivity to the ketone or the aldehyde within a short reaction time. The effect of water was explained as a medium capable to promote the oxidation of the alcohol to the ketone in a biphasic system assisted by phase transfer catalysis. This is particularly relevant for alcohols like 1-phenylethanol or benzyl alcohol that are not soluble in water at room temperature, and for which alternative oxidation routes are needed, as well as to switch on the catalytic activity of metal nanoparticles in a facile and green manner for the activation of molecular oxygen. Aliphatic alcohols like 1-octanol and 3-octanol were also tested, still showing Rh based catalysts as promising materials for this reaction if toluene only was used as solvent instead.


Publication metadata

Author(s): Weston JO, Miyamura H, Yasukawa T, Sutarma D, Baker CA, Singh PK, Bravo-Sanchez M, Sano N, Cumpson PJ, Ryabenkova Y, Kobayashib S, Conte M

Publication type: Article

Publication status: Published

Journal: Catalysis Science & Technology

Year: 2017

Volume: 7

Issue: 18

Pages: 3923-4236

Print publication date: 21/09/2017

Online publication date: 25/07/2017

Acceptance date: 18/07/2017

Date deposited: 31/10/2017

ISSN (print): 2044-4753

ISSN (electronic): 2044-4761

Publisher: Royal Society of Chemistry

URL: http://doi.org/10.1039/C7CY01006K

DOI: 10.1039/C7CY01006K


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Funding

Funder referenceFunder name
CHM-313485
CHM-313072
EPSRC
grant 148429

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