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wat is poppoffs rule?

wat is poppoffs rule?

Grade:12

4 Answers

Ashwin Sinha
520 Points
12 years ago

Dear Priyan Chawla,

When unsymmetrical ketones subjected to oxidation then direction or rapture of c-c bond takes placa in such a way that keto group always stay with smaller alkyl group.

Popoff's rule states that during oxidation of ketones, keto group always stays with the smaller alkyl group. For example,

CH3CH2COCH2CH2CH3 on oxidation with HNO3 gives two moles of propanoic acid, where in one mole of propanoic acid the cooh group comes from CH2 of propyl part of ketone.

CH3COCH2CH2CH3 on oxidation gives CH3COOH & CH3CH2COOH, here also the CH2 of propyl group is oxidised.

In both the examples the C=O remains with the smaller alkyl group,viz. CH3CH2 & CH3 respectively.

Mechanism is uncertain but probably proceeds with enol formation and depends on stability of enol

 

 

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Ashu kumar
14 Points
6 years ago
It is also called oxidation of ketones.popps rule is the oxidation of c-c Bond in which the group always staying and small alkyl group
Kushagra Madhukar
askIITians Faculty 628 Points
3 years ago
Dear student,
Please find the attached answer to your question below.
 
When unsymmetrical ketones subjected to oxidation then direction or rapture of c-c bond takes placa in such a way
that keto group always stay with smaller alkyl group.
Popoff's rule states that during oxidation of ketones, keto group always stays with the smaller alkyl group. For example,
CH3CH2COCH2CH2CH3 on oxidation with HNO3 gives two moles of propanoic acid, where in one mole of propanoic
acid the cooh group comes from CH2 of propyl part of ketone.
CH3COCH2CH2CH3 on oxidation gives CH3COOH & CH3CH2COOH, here also the CH2 of propyl group is oxidised.
In both the examples the C=O remains with the smaller alkyl group,viz. CH3CH2 & CH3 respectively.
Mechanism is uncertain but probably proceeds with enol formation and depends on stability of enol
 
Thanks for asking us your doubt.
Regards,
Kushagra
RISHIKA
550 Points
3 years ago
DEAR FRIEND
Popoff's rule states that during oxidation of ketones, keto group always stays with the smaller alkyl group. For example, CH3CH2COCH2CH2CH3 on oxidation with HNO3 gives two moles of propanoic acid, where in one mole of propanoic acid the cooh group comes from CH2 of propyl part of ketone.
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