Adas
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DPPP - new possible formation mechanism
Hello guys! It's me again and I want to share my theory with you.
Many people say that "DPPP" really exists and that they have made it, but I would rather like to go straight to the point - the chemical reactions
here because the original topic about "DPPP" had to be closed. If you want to join the discussion, you can post your ideas/observations or proofs,
but, please make a real scientific discussion. I don't want this one to end up like the original topic.
HERE you can find this theory, for example: | Quote: | | Theory.. HCl changes Acetone into Phorone (yellow green) and then into Pentachlorophorone which is an oily dark reddish liquid. When H2O2 is added the
Cl2 is split away and is replaced by the (O2)5... |
There are also some different theories about its formation (which I have read in the original topic, but I can't find it now), however, I have never
been very familiar with any of these. No offense, but some reaction steps that people mentioned seem like a nonsense to me. It would make sense that
H2O2 could oxidize HCl into chlorine, and this would then react with double bonds in phorone, but that would make TETRAchloride
and not PENTAchloride. The aldol condensation products are red themselves, I think the author missed this, too. Also, I don't see how hydrogen
peroxide could displace the chlorine from the molecule. Alkaline/alkaline earth metal peroxides could possibly do that, but hydrogen peroxide? It is
almost like one said that water could displace chlorine from organic compounds. It is not possible (in most cases), but we know that NaOH can do it.
However, a few days ago, I was testing Fenton's reagent for the first time. I oxidized lactic acid into acetic acid with it. It was a non-selective
oxidative decarboxylation. Next thing I thought about was oxidizing unsaturated compounds with it. Products of acetone aldol condensation (phorone
etc.) immediately came to mind, and I came with this brand new theory. I think it makes a lot of sense, even if it doesn't really work like that.
So here is some chemistry of Fenton's reagent (accord. to Wikipedia and other sources):
(1) Fe2+ + H2O2 → Fe3+ + OH· + OH−
(2) Fe3+ + H2O2 → Fe2+ + OOH· + H+
You can see that this reaction produces hydroxyl and hydroperoxy radicals. You may ask, what does the DPPP formation have to do with this? People use
HCl for the reaction. We know that every technical-grade HCl contains some iron. This could then create Fenton's reagent together with hydrogen
peroxide.
During aldol condensation, many different unsaturated compounds are being produced, but I will talk mostly about phorone, because it is the most
discussed one.
We all know that free radicals love to attack double bonds. The Fenton's reaction with phorone could look like this:
The image is mostly symbolic, of course, any radicals can take any place, but I used the simplest reactions so you could imagine it better. The last
reaction is probably incorrect, though. I don't know what I was thinking, don't pay attention on it.
But notice that even the first product contains pretty much oxygen in the molecule. Even if it contained just one hydroperoxy and 3 hydroxy groups, it
would be an explosive (though very oxygen-defficient). Furthermore, the original ketone group could be oxidized in a similar way in which acetone
peroxide is formed (it would condense 2 phorone units with 2 peroxide bridges). In addition to this, if the hydroxy groups attach near the original
ketone group, they could be also oxidized to ketone by hydroxyl radicals.
Next few possible reactions that come to mind are:
The reaction between hydroxy and hydroperoxy groups - which eliminates water and creates a peroxide bridge.
The reaction between hydroxy group and hydroperoxide radical or hydroperoxy group and hydroxyl radical which would create a double radical (like if a
DADP molecule was homolytically split), which could react with whatever else.
You can see that there are many possible reactions that could possibly take place, so I am afraid that "DPPP" is a term for molecule(s) with variable
size and composition.
There is also a problem with solubility, since higher aldol condensation products tend to form, which may not be soluble in H2O2
solution, so one would have to let it condense just enough, but not too much, to be able to do some useful reactions.
What do you, guys, think? I hope that I brought a little more clarity into this topic. This is my longest topic so far. 
Feel free to post your own ideas or tell me if I missed something.
Rest In Pieces!
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woelen
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One test could be to prepare phorone in pure form and try to react that with Fenton's reagent. I can imagine the first step of oxidation with
formation of OH-groups at different places, but why would there be formation of OOH-groups?
Another doubtful thing is the triple -C(=O)-C(=O)-C(=O)- structure in the center of the third molecule. I think that such a structure is very unstable
and I even doubt its possible existence. But an organic chemist may comment on this, I am not an expert in this field, it is just my guts telling me
that this structure is not stable.
An interesting experiment hence would be addition of phorone to dilute HCl. Does it indeed react forming a chlorinated compound? The experiment will
tell this. I agree with you, I think it does not get chlorinated by HCl.
Addition of H2O2 (without traces of Fe) and addition of H2O2 with Fe-ions added can be an interesing test. Do this with another acid than HCl, use
dilute reagent grade H2SO4, which certainly is free of iron. Repeat the experiment with intentionally some iron added. The observations of such
experiments will tell you more.
The main challenge for all these experiments will be to get phorone in a pure form. I think that will be hard, but here some organic chemist may be
helpful as well.
Altogether this may be interesting organic chemistry, related to acetone peroxide, but not in a k3wl/b4ng/boom setting. Many people made AP and some
of them lost fingers or worse, but I have never seen a nice interesting scientific treatment of the chemistry behind this compound. This chemistry is
interesting, and unfortunately this is spoiled by the k3wl type of persons who abuse this compound (or more likely: family of related compounds).
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franklyn
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This old chestnut has yet to bear fruit that anyone can cite , and not for
want of effort. The supposed compound is subject to the way it's precursor
can behave in it's synthesis. Mind that this is derived by dehydration of Acetone
therefore one should expect Phorone to be sensitive to hydrolysis side reactions.
Phorone ( diisopropylidene acetone )
IUPAC 2,6-Dimethyl-2,5-heptadien-4-one, sym-Diisopropylideneacetone
It's been known a long time
http://books.google.com/books?id=XxMKAAAAMAAJ&pg=PA165&a...
http://books.google.com/books?id=qXMMAAAAYAAJ&pg=PA342&a...
although what exactly is produced structurally can make all the difference.
Isophorone is a closed ring whereas the intended Phorone is open.
http://onlinelibrary.wiley.com/doi/10.1002/jctb.5010100106/abstract
www.sciencemadness.org/talk/viewthread.php?tid=228
www.sciencemadness.org/talk/viewthread.php?tid=1203
www.youtube.com/watch?v=ll8FLbJpR14
The end result if it is actually achievable remains elusive.
www.sciencemadness.org/talk/viewthread.php?tid=179#pid1185
www.sciencemadness.org/library/diphoronepentaperoxide.html
The properties claimed for it are shall we say dubious.
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AndersHoveland
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I have already proposed my own reaction mechanism:
https://sites.google.com/site/energeticchemical/dppp
It is really not that far fetched. There is already much available literature on the peroxidation of mesityl oxide, which is related to pherone.
I happen to believe that the patent does indeed describe a novel new peroxide, but that the investigators made many false assumptions, in large part
because they did not have modern analysis methods available to them at that time.
I believe that the molecular structure of "DPPP" could best be represented by one of the following diagrams, although it is not unlikely the real
structure may be an intermolecular amorphous substance.
-----------------------------------------------------------------------
There are several different potential reaction pathways. Below is a possible mechanism for the peroxidation of pherone. The entire mechanism would be
too long and complicated to show, but it gives a good idea how pherone can react with H2O2, and ultimately form a peroxidated dimer (not shown).
From diagram 3 to 4 in the above image, the enol would just be oxidized by H2O2. Oxidation of acetone to peroxyacetone by hydrogen peroxide at low
pH, and in the presence of acetic acid, is well known. This particular reaction could be another complicated topic, so I will not go into detail
here.
This is not the only possible reaction mechanism.
----------------------------------------------------------------------
Actually, those unsaturated double bonds can be oxidized more easily than you think. It does not require anything as powerful as •OH, and besides
hydroxyl radicals would not be very selective either. If there is a radical mechanism, I think the presence of chlorine radicals and activated singlet
oxygen is sufficient to explain it. Both these two oxidizing intermediates would be present in the reaction containing hydrogen peroxide with
concentrated hydrochloric acid.
Alkenes and the enol tautomer of ketones are also susceptible to radical attack/peroxidation, and alkenes are known to be able to be peroxidated by
reaction with activated O2 in the ene reaction. (obviously plenty of activated O2 being created when the HCl is slowly catalyzing the
decomposition of the hydrogen peroxide)
Singlet oxygen reacts with an alkene -C=C-CH- by abstraction of the allylic proton (in an "ene" type reaction) to the allyl hydroperoxide.
H.H. Wasserman, J. L. Ives, Tetrahedron volume 37, p1825-1852, (1981).
The alkyl groups viscinal to the alkene would be suceptible to abstraction of a hydrogen ion because the allylic radical is surprisingly stable.
CH2=CH-CH3 + R• --> CH2=CH-CH2• + RH
( R• in this case could be a chlorine radical, for example)
This is an example of an "allylic radical", with its stabilizing resonance:
•CH2-CH=CH2 <==> CH2=CH-CH2•
The allylic radical can then react with activated O2 to form the radical:
CH2=CH-CH2-O-O•
Which can then react with the RH repeating the cycle, since another R• is released again.
The corresponding "allyl hydroperoxide" with this simplified example would be:
CH2=CH-CH2-O-OH
This could explain how the terminal methyl groups in the pherone get peroxidated.
[Edited on 17-4-2013 by AndersHoveland]
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Adas
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Quote: Originally posted by woelen  | | I can imagine the first step of oxidation with formation of OH-groups at different places, but why would there be formation of OOH-groups?
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-OOH groups would be created from the hydroperoxide radicals that are also created in Fenton's reaction.
| Quote: Originally posted by woelen | | Another doubtful thing is the triple -C(=O)-C(=O)-C(=O)- structure in the center of the third molecule. I think that such a structure is very unstable
and I even doubt its possible existence. |
Yeah I also thought about that.
| Quote: Originally posted by woelen | An interesting experiment hence would be addition of phorone to dilute HCl. Does it indeed react forming a chlorinated compound? The experiment will
tell this. I agree with you, I think it does not get chlorinated by HCl.
Addition of H2O2 (without traces of Fe) and addition of H2O2 with Fe-ions added can be an interesing test. Do this with another acid than HCl, use
dilute reagent grade H2SO4, which certainly is free of iron. Repeat the experiment with intentionally some iron added. The observations of such
experiments will tell you more.
The main challenge for all these experiments will be to get phorone in a pure form. I think that will be hard, but here some organic chemist may be
helpful as well.
Altogether this may be interesting organic chemistry, related to acetone peroxide, but not in a k3wl/b4ng/boom setting. Many people made AP and some
of them lost fingers or worse, but I have never seen a nice interesting scientific treatment of the chemistry behind this compound. This chemistry is
interesting, and unfortunately this is spoiled by the k3wl type of persons who abuse this compound (or more likely: family of related compounds).
|
True. This would involve higher-level chemistry, analyses etc.
I was always interested in the mechanism of TATP formation, but every source says something different, so I find this a little confusing.
Maybe it starts with the formation of enol (because of acid), then H2O2 adds on the double bond, which creates propane-2-ol-2-hydroperoxide, which
releases water instantly (I believe, because it would be very very unstable, gem-diols also tend to release water) and turns into DMDO (or a radical
derived from this), which then reacts with other DMDO molecules/radicals to form DADP and then TATP.
Rest In Pieces!
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AndersHoveland
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| Quote: Originally posted by Adas | | -OOH groups would be created from the hydroperoxide radicals that are also created in Fenton's reaction. |
I do not think the reaction proceeds through hydroxyl or hydroperoxide radicals. If it did, the pherone would be destructively oxidized, and
there would not be any DPPP remaining. Whatever the structure of "DPPP" is, it is a very big molecule, and even one carboxyl group would likely render
the whole thing water soluble and the yields would then be negligible.
I think you should take another look at the chlorine radical - oxygen cycle. A single chlorine radical could trigger a cascade of numerous pherone
molecules reacting with oxygen, and assuming there was a higher concentration of oxygen than free chlorine, the pherone would be almost entirely
peroxidated, not chlorinated.
Indeed, in the gradual catalytic decomposition of H2O2 by hydrochloric acid, there is only a very small ammount of free chlorine existing at any
instant in time.
However, I am not entirely sure that a radical reaction mechanism is even needed to explain the formation of DPPP. I think there is much insight to be
gained by looking at the reaction between mesityl oxide and hydrogen peroxide, which is well described in the literature.
[Edited on 17-4-2013 by AndersHoveland]
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