January 15, 2025, 12:59:54 PM
Forum Rules: Read This Before Posting


Topic: how is aldehyde converted to carboxylic acid by hydrogen peroxide in ozonolysis?  (Read 5956 times)

0 Members and 1 Guest are viewing this topic.

Offline ABC

  • New Member
  • **
  • Posts: 5
  • Mole Snacks: +0/-0
It seems like an oxygen is added to the H that bonded with carbon, but I can't think of how that happens in a acid-base reaction.

Offline CaverKat

  • Regular Member
  • ***
  • Posts: 32
  • Mole Snacks: +2/-0
Not an acid-base reaction.  If you're going from an aldehyde to carboxylic acid, it's a redox reaction.

http://www.organic-chemistry.org/synthesis/C1O/carboxylicacids/oxidations.shtm


Offline ABC

  • New Member
  • **
  • Posts: 5
  • Mole Snacks: +0/-0
Not an acid-base reaction.  If you're going from an aldehyde to carboxylic acid, it's a redox reaction.

http://www.organic-chemistry.org/synthesis/C1O/carboxylicacids/oxidations.shtm



Okay. Can you explain how that works? I thought redox reaction involves only electrons?

Offline CaverKat

  • Regular Member
  • ***
  • Posts: 32
  • Mole Snacks: +2/-0
Acid-base reactions typically involve charged species (I'm pretty sure), and involve transfer of protons and/or hydroxyl groups.

I've just learnt in organic chemistry, you know... "Loss of hydrogen = oxidation, gain of H = reduction."  I know that it's something to do with the saturation level of C and changing the number of bonds  it has to heteroatoms changes its oxidation level.  i.e. CO2 level ) 4 bonds), carboxylic acid level (3 bonds), ketone/aldehyde level (2 bonds), alcohol level (1 bond) and alkane level (0 bonds and saturated) - no mechanism though

I see what you mean though... with calculation reduction potentials.  I've sort of divided my brain into two sections when it comes to redox.  One side for organic and one side for inorganic :)  I have a feeling that they're the same, though, with the electrons and what not.

Offline UG

  • Full Member
  • ****
  • Posts: 822
  • Mole Snacks: +134/-15
  • Gender: Male
Okay. Can you explain how that works? I thought redox reaction involves only electrons?
Yes, electrons are involved. The aldehyde is oxidised
R-CHO + H2O  :rarrow: R-COOH + 2H+ + 2e-

Offline orgopete

  • Chemist
  • Sr. Member
  • *
  • Posts: 2636
  • Mole Snacks: +213/-71
    • Curved Arrow Press
Most oxidations have the following form (sans curved arrows):

H-C-O-X  :rarrow: H+ + C=O + X-

There are many variants of this in the manner in which the proton is abstracted and the leaving group leaves. Perhaps it is protonated so it can leave as a neutral molecule.

You should be able to draw something similar with an aldehyde and hydrogen peroxide. Water is a likely base and most of these reactions are acid catalyzed, so neutral water is a possible leaving group.

RCHO + H2O2  :rarrow: RHC(=O)-O-OH  :rarrow: RCOOH + H2O
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

Offline ABC

  • New Member
  • **
  • Posts: 5
  • Mole Snacks: +0/-0
Hm.. I think I kind of understand now. Thanks!

Sponsored Links