Talk:Ozonolysis

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Nucleophile participation mechanism[edit]

The mechanistic scheme should incorporate the solvent participation mechanism. For example in methanol, the carbonyl oxide undergoes attack to give an alpha-methoxyl hydroperoxide. This can be conveniently incorporated by an arrow going right in the current scheme. I lack the technical skills to do this. DavidRKelly 17:56, 23 June 2007 (UTC)

1,3-dipolar cycloaddition[edit]

It would be better (more correct) to write 1,3-dipolar cycloaddition (in the scheme) and also mention this in the text (which would allow to link to the 1,3-dipolar overview page), or even (2+3) cycloaddition or [2+4] cycloaddition, according the IUPAC rules: www.iupac.org/goldbook/C01496.pdf

Quoting the text: which is hydrolysed to form... I have the feeling, that "hydrolysis" is a fuzzy term. But it is maybe a question of the definition of "hydrolysed"...

Criegee Intermediate is mislabeled[edit]

The diagram has the Criegee Intermediate mislabeled. The zwitterionic intermediate (sometimes with the carbonyl compound) is considered the Criegee Intermediate.

I confess that although I teach ozonolysis every year, I wasn't familiar with the term "Criegee intermediate", since this isn't mentioned in textbooks I have used (see for example Wade, 6th ed., page 361). However a quick web search gives [this article, and this site is usually pretty reliable. This states that the molozonide is called the Criegee intermediate, as shown in the diagram. Can you provide an authoritative source to say otherwise? I will check March tonight. Walkerma 22:47, 12 November 2005 (UTC)
The Criegee intermediate is the same as carbonyl oxide. See for example my paper in CPL and references herein. It should be corrected RedAndr 00:34, 16 May 2007 (UTC)
Thanks for the ref. I did a quick & dirty fix on the image, I will try and create a new one from scratch when I get time. Thank you! Walkerma 07:18, 16 May 2007 (UTC)
Thank you. I would also suggest to include to the scheme primary and secondary ozonides as synonyms for molozonide and trioxolane. Actually this scheme is correct only for liquid phase, in gas phase the primary ozonide just decomposes to carbonyl oxide and carbonyl, without formation of the secondary ozonide. Such process occurs in the atmosphere, for instance. It could be mentioned also. RedAndr 14:47, 16 May 2007 (UTC)

Mechanism shown is wrong[edit]

The arrows on the molozonide are wrong, look at the charges involved and the movement of electrons. For the correct mechanism see Clayden, Greeves, Warren and Wothers page 938.

Harries Ozonide reaction[edit]

Harries Ozonide reaction article is not up to wiki standards, images missing, mechanism already covered in ozonolysis V8rik 22:47, 4 December 2006 (UTC)

Ozonolysis of Alkynes[edit]

According to Carey in Organic Chemistry, alkynes can also undergo ozonolysis to yield carboxylic acids. Unlike with alkenes, the only reagents are ozone and then water (no zinc is required). Because of this, it seems that this article should give a more general definition of ozonolysis and then maybe have a section for alkenes and a section for alkynes. Here is another reference.

Carhas0 18:51, 10 December 2006 (UTC)

Article Review[edit]

- overall: this article is all over the place. there are even editorial comments right in the article! - lead: technically correct, but pretty unclear; doesn't indicate the usual purpose of ozonolysis - mechanism section: this needs to be reworked. in no case can the ozonide be considered to be hydrolysed, which implies reaction with water. the difference between malozonide and ozonide is not clearly marked. the difference between different workup conditions is not noted. the role of methanol, a common co-solvent, or pyridine, a common additive, is not mentioned. the use of dyes is not mentioned. - mechanism diagram: this is a [3+2] cycloaddition between a 1,3-dipole, ozone, and a 2pi olefin. first step: right arrow should originate from olefin. typically, "[3+2]" is written above the arrow. second step, missing arrow from rightmost oxygen lone pair. third step: lone pair should be drawn. - "corrected mechanism": also has errors. sigma bonds never attack lone pairs! - history: why does this section come after the mechanism section? - alkynes: i never see this used. are there sources for this? - what about some more modern stuff? like the schreiber procedure for giving differentially terminated products? or this new NMO-based procedure? nowhere are standard conditions given either... - summmary: good start, but article needs work.

Eugene Kwan 23:02, 27 January 2007 (UTC)

Eugenol[edit]

The structure of eugenol is depicted incorrectly in the ozonolysis example; likewise the products of the ozonolysis of eugenol are improperly depicted. This is really terrible and shows this article is not factually based.

128.61.92.32 (talk) 02:44, 10 November 2008 (UTC)

Thank you. On checking the cited reference for this example, I see that there is indeed a -CH2- missing between the benzene ring and the C=C double bond in eugenol, whose structure is also shown here. The same -CH2- is missing in each intermediate and in the final aldehyde product. Could someone redraw the figure?

Please try however to avoid comments such as your last sentence. It is better to just point out the error and describe it as well as you can. Dirac66 (talk) 03:13, 10 November 2008 (UTC)

Fixed. I also scrapped the second copy of the intermediate. There are indeed two such structures, differing in absolute stereochemistry. However, the stereochemistry wasn't included and it doesn't matter for this reaction (they both converge to the same product) so I didn't feel like cluttering up the reaction. DMacks (talk) 03:45, 10 November 2008 (UTC)

Good, the reaction is not stereoselective anyhow so there is no need to show both isomers.


128.61.92.32 (talk) 23:18, 10 November 2008 (UTC)

No mention of the kit required?[edit]

Article would be improved (IMO) if the kit and use of appratus were described. - Quantockgoblin (talk) 23:23, 8 October 2009 (UTC)

I agree, especially along with a a photograph of typical reaction setup (O2 source, ozonizer, gas bubbling through reaction solution, maybe even the nice blue color visible). We have a whole section in ozone about generators, so a schematic there of the standard lab-bench model would be good also. Not quite sure what you mean by "the kit". DMacks (talk) 01:15, 9 October 2009 (UTC)

Need details about second step (workup)[edit]

There are scattered comments in the article that after the O3 is used, other chemicals are used for workup, and that depending on their nature, the products of the overall reaction might vary. Most of these ideas are not cited (especially the assertion about which ones are more common). And there's no discussion of how they work (what are the byproducts, for example, or reaction mechanisms) or pros/cons (if there are practical or chemical reasons rather than just standard "different things work best for different substrates"). DMacks (talk) 12:45, 29 May 2014 (UTC)