Sciencemadness Discussion Board

Ozonolysis

ODBAL - 9-11-2016 at 03:36

Hi everyone,

This is my first post. I have just received a new ozone generator and I want to give a go at splitting some alkenes. Specifically I'd like to try the ozonolysis of styrene mostly because it is a terminal alkene that would yield fairly distinctly identifiable carbonyl species.

My concerns are that I've never tried this reaction before, so I am unfamiliar with the work-ups. I have a set of glassware dedicated to peroxide like stuff that I can put behind a blast shield.

If I wish to follow this up with a reduction of the ozonide, what might the procedure be like for say Zn/AcOH? or NaBH4? Do I just dump in a mixture of the reducing agent after the reaction is finished?

Rhodanide - 9-11-2016 at 09:31

Quote: Originally posted by ODBAL  
Hi everyone,

This is my first post. I have just received a new ozone generator and I want to give a go at splitting some alkenes. Specifically I'd like to try the ozonolysis of styrene mostly because it is a terminal alkene that would yield fairly distinctly identifiable carbonyl species.

My concerns are that I've never tried this reaction before, so I am unfamiliar with the work-ups. I have a set of glassware dedicated to peroxide like stuff that I can put behind a blast shield.

If I wish to follow this up with a reduction of the ozonide, what might the procedure be like for say Zn/AcOH? or NaBH4? Do I just dump in a mixture of the reducing agent after the reaction is finished?


Here's a thread about Ozonolysis, it might help you, it might not. Cheers! Link: http://www.sciencemadness.org/talk/viewthread.php?tid=13467

zed - 9-11-2016 at 15:45

Ummm. Styrene. I'm not sure Styrene will do what you want it to.

Now, Iso-eugenol..... That can be done. Maybe even profitably.

Vanillin, produced from Iso-eugenol, is sometimes offered as "Natural Vanilla". It is after-all, produced by cleaving isomerized Clove oil. Eugenol derived Vanilla, sells for a premium price.

https://www.google.com/patents/US2916499

And, the patent suggests, no reduction is required.

[Edited on 9-11-2016 by zed]

ODBAL - 16-11-2016 at 20:46

Quote: Originally posted by zed  
Ummm. Styrene. I'm not sure Styrene will do what you want it to.

Now, Iso-eugenol..... That can be done. Maybe even profitably.

Vanillin, produced from Iso-eugenol, is sometimes offered as "Natural Vanilla". It is after-all, produced by cleaving isomerized Clove oil. Eugenol derived Vanilla, sells for a premium price.

https://www.google.com/patents/US2916499

And, the patent suggests, no reduction is required.


That patent certainly has my interest, and may have to be a separate project in itself. However it seems to describe a different reaction in which water or the protic solvent is involved. I'm more interested in the textbook reaction with formation of ozonide intermediate followed by a reduction. Furthermore, I wonder what you mean about it not working? Are you referring to just what the patent says? I'm certain that if I am to obtain benzaldehyde from styrene there will need to be a more traditional procedure, but it should be possible yielding formaldyde.


My rough expectations for this reaction are that:
I should ozonate a dilute solution of my ethylenyl compund until saturation under O3/O2 and with reduced temperature to enhance ozone absorption and slow the rate of reaction.

After it is indicated that the solution has an excess of O3, further flushing with O2 and simply quenched (do I need TLC monitoring here or is it that quick?) with a solution of dimethyl sulfide or thiourea.

And then separation with water/ether extraction.

Any tips (especially on safety) would be appreciated.

[Edited on 17-11-2016 by ODBAL]