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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: slizza on September 10, 2012, 12:24:17 PM

Title: Geraniol oxidation to Geranial by MnO2
Post by: slizza on September 10, 2012, 12:24:17 PM
Hi all

I have a report based upon the oxidation of the primary alcohol geraniol into geranial by using MnO2 and have been given a couple of questions that have had me stopped in my tracks.

1. What is the mechanism for the oxidation of alcohols by MnO2

2. why does the H NMR spectrum of commercial geranial contain a second aldehyde signal?


If anyone is able to help me with these questions i would be really grateful.



Thank you.
Title: Re: Geraniol oxidation to Geranial by MnO2
Post by: discodermolide on September 10, 2012, 01:07:34 PM
Have a look here for the mechanism http://msmith.chem.ox.ac.uk/summaries1-4.pdf (http://msmith.chem.ox.ac.uk/summaries1-4.pdf)
Is the commercial material a mixture of double bond isomers? This would explain two signals
Title: Re: Geraniol oxidation to Geranial by MnO2
Post by: slizza on September 10, 2012, 06:00:33 PM
Hi man and thanks for the reply!



Geranial (AKA Citral A) is the trans product, are you saying the minor product (the ciz product) would cause the second aldehyde signal?



here is a wiki like to geranial: http://en.wikipedia.org/wiki/Citral (http://en.wikipedia.org/wiki/Citral)
Title: Re: Geraniol oxidation to Geranial by MnO2
Post by: discodermolide on September 10, 2012, 10:25:14 PM
You used commercial materials. What do you mean by this? Did you have a certificate of analysis?
How big is the second aldehyde peak with respect to the first?
Title: Re: Geraniol oxidation to Geranial by MnO2
Post by: slizza on September 11, 2012, 09:34:58 AM
I have not produced commercial geranial, the question i was given asks why two aldehyde peaks would appear when commercial geranial is produced.
Title: Re: Geraniol oxidation to Geranial by MnO2
Post by: discodermolide on September 11, 2012, 09:41:55 AM
Because it a mixture of double bond isomers.
Title: Re: Geraniol oxidation to Geranial by MnO2
Post by: slizza on September 11, 2012, 10:09:40 AM
thank you!