Return to Contents Chapter 15: Alcohols, Diols and Thiols Ch 15 contents

Oxidation of Alcohols

general scheme for the oxidation of alcohols

Reaction type: Oxidation-Reduction

Summary

reagents for the oxidation of alcohols
oxidation of RCH2OH
oxidation of R2CHOH
oxidation of R3COH
Cr OXIDATION OF ALCOHOLS
The mechanism is not trivial, so attention here is focussed on the actual oxidation step. Prior to this, the alcohol reacts to form a chromate ester (shown). A base (here a water molecule) abstracts a proton from the chromate ester, the C=O forms and a Cr species leaves. 
This demonstrates the importance of the carbinol H to this mechanism.
oxidation of alcohols
QUESTIONS
What type of reaction could the oxidation step be decribed as ? ANSWER
What is the oxidation state of Cr in chromic acid ? ANSWER
What is the oxidation state of the Cr in the chromate ester intermediate ? ANSWER
What is the oxidation state of the Cr in the "leaving group", HCrO3- ANSWER
 
Study Tip:
If you see Cr reagents, you are probably looking at an oxidation reaction.
Most likely the oxidation of an alcohol or an aldehyde

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© Dr. Ian Hunt, Department of Chemistry, University of Calgary