so i was brushing up on my organic chem over the last month and i found that aldehydes oxidize but ketones do not. so i'm sitting there thinking "what about AP" and decide its an exception to the rule. my question is, under what circumstances will a ketone oxidize and is this the reason AP is relatively unstable?

------------------
Long

Ass

Sig

I don't know if this will be of any use to you, but it has some information on oxidation of ketone bodies.

http://medlib.med.utah.edu/block2/biochem/Rechsteiner/Rechsteiner%20Notes/MCR2.html

[edit] this link may also be of use.
http://www.chem.uic.edu/web1/OCOL-II/WIN/CH20/YIELD.HTM
------------------
We have assembled here today to teach you all a little lesson. One cannot remain on top for years while closing one's mind to the influence of others. I will demonstrate the true meaning of inovation for all you to see.

[This message has been edited by RTC (edited December 28, 2001).]

Hmmm... I've never heard about the ability of ketones to oxidize other substances. This doesn't mean that it doesn't exist, but I'm almost sure that this isn't the reason for AP's sensitivity. This is rather due to the -O-O- bond which seems pretty unstable to me (just a supposition).

Happy New Year everybody
Rhadon

AP isn't a ketone.

Yes, of course :) - how did i get the idea that it is one :confused:?

Maybe because acetone IS a ketone. It would be logical (though inaccurate) to assume that AP, being made from acetone, would also be a ketone.

I wouldnt say that AP is a ketone, nbk. For being defined as a ketone, the substance must have the functional group (I hope thats the correct translation) of a ketone like<font face="courier new" size="2">

R
|
C=O
|
R</font>

AP has no such structure. Why should something made from a ketone also be a ketone? If you e.g. oxidize an aldehyde you get a carbonic acid.

I suppose that the reason for the unstability of AP is just simply the fact that it is a peroxide. Im not aware of any stable peroxide. As Rhadon said, O-O bonds are very weak.

[ January 06, 2002: Message edited by: PYREX ]</p>

Please re-read my above post more carefully. You see that I didn't say AP was a ketone.

I said that, being made from a ketone, that one may be lead to believe (incorrectly) that it too was a ketone (which it isn't).

Get it straight.

Sorry 'bout that, I was a bit confused because you said that it would be "logical".

to clear some things up: i never meant that AP in itself was a ketone. just that acetone was and by adding a oxidizing agent to it (H₂O₂ you are oxidizing a ketone. normally this wouldnt happen.

Does anyone know why PHILOU Zrealone doesn't post anymore? He'd surely have something interesting to say to this.

He sent me an email about hydrazinum nitroformate lately, but he's out of the country often. I've sent him an email pointing out his help is needed.... ;)

Ketones will not nomaly oxidise. The production of AP is no exception. Acetone is not oxidised as such.

I thought it was produced by nucleophilic addition of the H2O2 to the acetone. I was sure of this, ive researched a few txtooks, and the web can't find anything for sure though. It seems to work butIhavnt got a structural diagram of AP to hand so I cant be sure.

VX

The formation of acetone peroxide really isn't an oxidation reaction; it basically an addition reaction. Other peroxides do form but they are so unstable that they decompose immediately at terrestial temperatures.

I dont understand much of the chemistry here but does any of the information in a_bit_of_info_on_ap.pdf help? It is on the FTP site.

Ketons are ketons!
Ketons are more resistant to oxydation that the parent aldehydes; this doesn't mean ketons can't be oxydised!
Ex:
Does aldehyde spontaneously oxydise in air; yes; after a while, carboxy acids are formed!
Does ceton spontaneously oxydise in air; depends on side groups, but normaly no!
Do both burn and oxydise with hot air at flame exposure? YES!

So everything is a question of reactants, and heat; the same applies to everything; if you get the right tools everything is possible!

Now about organic chemistry nomenclature!
R-OH is an alcohol (1 OH linked to a C)
R-O-R is an ether! (1 O linked to two C)
R-O-O-R is a peroxyether (2 O linked each to a C)
R-CH=O is an aldehyde (1 O linked twice to a C holding a H)
R-CH(OH)2 is an aldehyde hydrate (two OH linked to a C holding a H)
R-CH(OH)-O-R is a hemiacetal (1 O linked to two C one of those hold an H and an OH)
R-CH(-OR)2 is an acetal (2 OR linked to a C holding a H)
R-CO-R or (R)2C=O is a ceton (1 O linked twice to a C holding no H, only C links)
R-C(OH)2-R or (R)2C(OH)2 is a ceton hydrate (two OH linked to a C holding no H)
(R)2C(OH)(-OR) is an hemicetal (1 OH and 1 OR linked to a C holding no H)
(R)2C(-OR)2 is a cetal (two OR linked to a C holding no H)

Now what's the point:
(CH3)2C(O-O)2C(CH3)2 and CTAP belongs to one of the above families:
peroxy first since you have O-O linkage;
secondly watching (R2)2C(-O-R')2
means two O linked to a C holding no H; you conclude cetal (R'= O-R)!
Result of reflexion:
Aceton is a ceton since CH3-CO-CH3 is its formula; but CTAP or CDAP are cycloperoxyacetal and thus different from cetons!

Arrgh... stupid me. Post "deleted", sorry.

<small>[ March 21, 2002, 10:43 AM: Message edited by: Zambosan ]</small>