I have gone across several articles that have mentioned the below:

  1. Alkenes on reaction with O3 and Zn/H2O or any other reducing agent gives aldehyde/ketone.
  2. Alkenes on reaction with O3 and H2O2 gives carboxylic acid/ketone.
  3. Alkynes on reaction with O3 and Zn/H2O gives acid anhydride/diketones.
  4. Alkynes on reaction with O3 and H2O gives carboxylic acid/diketones.

But, no book or article mentions what would happen if ozonolysis of alkenes occurs with water. Would it give aldehyde/ketone or carboxylic acid/ketone?

  • $\begingroup$ Presence of water does not really influence the outcome of ozonolysis $\endgroup$
    – Waylander
    Commented May 5, 2023 at 18:01

1 Answer 1


Formation of aldehydes, ketones and acids depend on the type of alkene. Let's start with the most basic alkene(ethene), on ozonolysis of ethene we get 2 equivalents of formaldehyde. On ozonolysis of 2-butene, we get 2 equivalents of acetaldehyde. To get ketone as product, we need to use a second degree alkene, let's say 2-methyl-propene. On ozonolysis of 2-methyl-propene, we get propan-2-one and formaldehyde, so you can see that we need different types of alkenes for different types of product. Now talking about carboxylic acid formation, it does not form simply by only ozonolysis. We have to add an extra oxidising agent for example per acid that will oxidise the aldehyde formed by ozonolysis to carboxylic acid. So with water, it will not yield carboxylic acid but can yield aldehydes and ketones. Hope this helps.


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