Adas
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Ozone oxidation of -NH2 groups
Hello,
I wanna ask, if it is possible to oxidize -NH2 groups to -NO2 groups using ozone. Ozone is extremely powerful oxidizing agent in general.
Will the reaction need any catalyst?
What about making dinitroethane from ethylene diamine? I haven't found ANY infos on dinitroethane, so I think it can't be produced this way.
Or?
Thanks
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hissingnoise
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Ozonation of ethylene diamine is likely to give a mixture of products which could include nitrates and nitrites.
Oxidation by HTP might be a better bet!
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Adas
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Quote: Originally posted by hissingnoise  | Ozonation of ethylene diamine is likely to give a mixture of products which could include nitrates and nitrites.
Oxidation by HTP might be a better bet!
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I have no idea what HTP is 
Have you tried sth like that? Or have you any refference? I would like to read something about it.
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hissingnoise
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I found this patent for 1:2-dinitroethane!
Its preparation is difficult and its stabilisation more so!
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hissingnoise
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HTP= high-test-hydrogen peroxide!
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AndersHoveland
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oxidation of amines
As you can see in the image, alkyl amines can be oxidized by H2O2 to alkyl hydroxylamines, and then to oximes.
reaction of secondary amines with H2O2 produces nitrones. For example, CH3CH2CH-NH-CH2CH2CH3 is oxidized to
CH3CH2CH=N(-->O)-CH2CH2CH3 in 89% yield.
(where the compound is an N-oxide, there are not any carbon-oxygen bonds)
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv9...
http://www.sciencedirect.com/science/article/pii/00404039950...
http://docs.google.com/viewer?a=v&q=cache:bNaeoQOt0koJ:w...
It appears that a catalyst is required, whether tungstate, selenium dioxide, or titanium-silicate zeolite.
| Quote: |
Titanium "zeolite" catalyst
Selective mono N-oxidation of substituted pyrazines in good yields using 30% dilute H2O2 as an oxidant with a specially prepared titanium silicate
catalyst is possible.
Preparation of the Catalyst:
Add a solution of titanium peroxide to ethyl silicate (with or without an organic solvent) to obtain a gel. Hydrolyze the homogeneous gel previously
obtained, by adding an organic base to the gel. The ammount of organic base should be only 6-15% of the ammount of silica gel. Next, add deionised
water after the yellowish-white color of the gel begins to turn into a greenish-white color. Stir the greenish-white gel for about 1 hour, then heat
the gel in a pressure cooker at 100 -110 C. The gel must be constantly heated in this way for at least 20 hours. Further heating, up to 2 days, is
preferable. This will result in a solid composite product. Separate out the resultant solid composite material, dry, and bake at a 350-500C
temperature to obtain the final product. This is a catalyst and so only a small quantity need be prepared. The organic base should be an organic amine
with lots of bulky organic groups on it, either a tri- or tetra-alkyl amine, such as tetrapropyl ammonium hydroxide. Alternatively positively charged
coated silica particles can be used instead of the ethyl silicate. These can be prepared by mixing an aqueous colloidal silica with stabilized basic
aluminum acetate. The aluminum composition is stabilized with a small quantity of boric acid, which controls the hydrolysis of the aqueous solution of
basic aluminum acetate.
The catalyst produced above is known as TS-1 and is basically a porous titanium silicate crystal with a structure analogous to zeolite. TS-1 is not
yet commercially available. It can also catalyze the oxidation by H2O2 of imines R2C=NH into oximes R2C=NOH.
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http://docs.google.com/viewer?a=v&q=cache:nD_IrqfdCTsJ:w...
For more information about these types of reactions, you might see the topic in this forum about the reaction of ammonium hydroxide with hydrogen
peroxide.
http://sciencemadness.org/talk/viewthread.php?tid=11781
Essentially the reaction between NH4OH and H2O2 is extremely slow (most of it will still be unreacted after several days), somewhat faster (several
hours) when refluxed (boiled). But a combination of a ketone and acetamide can apparently be used as a catalyst. Ammonium nitrite, or nitrate, are the
reaction products.
Oxidation of Ammonia and Amines by Ozone
Apparently, ozone attacks ammonia, but typically not ammonium salts such as NH4NO3. From wikipedia:
"Ozone does not react with ammonium salts but it oxidizes with ammonia to ammonium nitrate:
2 NH3 + 4 O3 → NH4NO3 + 4 O2 + H2O "
Typically, it is very problematic to oxidize alkyl amines (such as methylamine) with ozone, as mostly other undesirable byproducts result and the
yields of nitroalkanes are very low.
Oxidation of Aromatic Amines
The chemistry of amino groups is very different if they are on a benzene ring. Aryl amines (such as aniline) can more easily be oxidized to nitro
compounds by persulfate at 8degC using acetone as a solvent (the yields were much lower at room temperature or using water as a solvent), and buffered
with sodium bicarbonate.
Oxidation of Nitroso Groups
Nitroso groups, —N=O , can also be oxidized to nitro groups. Usually they can be easily oxidized by dilute H2O2, or by passing nitrogen dioxide into
the solution. However, nitrosamines, R2N—N=O , are much more difficult to oxidize into nitramines. Typically peroxytrifluoroacetic acid is required
for those types of selective oxidations.
Tautomerism between Oximes and Nitrosoalkanes
Nitrosomethane exists as a tautomer of formaldoxime. Formaldoxime generally exists as the trimer of CH2=NOH. The oxime readily polymerizes at room
temperature and is more stable in aqueous solution.
| Quote: Originally posted by Sauron |
In monomeric form [nitrosomethane] is a blue gas. But it is usually isolated as its dimer Me-N(O)=(O)N-Me which is a solid, which rearranges to the
gas when heated above its melting point. Further heating produced trimeric formaldoxime.
At ordinary temperatures nitrosomethane slowly changes into the formaldoxime cyclo(-N(OH)-CH2-}3, a six membered heterocycle C3H9N3O3
Freshly prepared formaldehyde oxime hydrochloride (formaldoxime monomer) ... [can be prepared]. Formldehyde oxime monomer HCl from hydroxylamine
hydrochloride and formalin soln. The oxime is extracted with ether after salting out with CaCl2. Nitrosomethanes are easily oxidixed to nitromethanes.
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Pure monomeric CH2=NOH can be extracted with ether, at pH 8 , shortly after combining aqueous solutions of formaldehyde and hydroxylamine, but in the
presence of hydrochloric acid only the trimer is formed. The monomer is a liquid boiling at 83-85degC, which readily polymerizes to an amorphous
solid, which could not be recrystallized.
So from what I can see, it may likely be possible to oxidize methylamine to nitromethane using hydrogen peroxide.
[Edited on 2-11-2011 by AndersHoveland]
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Sedit
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Is there reagents that can perform this operation on amino acids without destruction of the carboxylic function? The only thing I remember being able
to do so is DimethylDioxirane but I have to relocate the reference for this.
I would like to attempt this with Glycine and have it undergo cross coupling Kolbe reaction with Sodium acetate as this would be good practice for
Kolbe electrolysis and yield very useful Nitroethane as the product. The Nitro group instead of the amine of glycine would place yeilds in the high
70-90% range due to the Electron withdrawing nature of the R-NO2 stabilizing the formed intermediate that normally leads to substitution with the
solvent in Kolbe coupling. This would(should) not occur in this case and allow for methylation of the formed radical in decent yeilds.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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AndersHoveland
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The Sandmeyer reaction can also often be used to replace the amino groups with nitro groups.
For example, 5-amino tetrazole can be converted to 5-nitro tetrazole by treatment with Cu(NO2)2 and HNO3.
http://www.sciencemadness.org/talk/viewthread.php?tid=12938
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AndersHoveland
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| Quote: Originally posted by Sedit | | Is there reagents that can perform this operation on amino acids without destruction of the carboxylic function? |
The persulfate method mentioned in my last post came from a paper where they specifically used aryl amines with carboxyl groups also on the rings, and
the carboxyl groups where mostly left alone. But the persulfate method might be too harsh an alkyl amines, such as those found on amino acids.
| Quote: Originally posted by Sedit |
I would like to attempt this with Glycine and have it undergo Kolbe electrolysis to yield very useful Nitroethane as the product.
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Interesting idea, although the main reaction product [assuming excess acetate was used] would of course likely be ethane, with traces of
1,4-dinitrobutane also potentially forming.
One potential problem with your idea is that, while it may work at the anode, the nitro groups are likely to be reduced at the cathode.
http://www.sciencemadness.org/talk/viewthread.php?tid=4145
"electrochem reduction of 1-nitroalkenes to amine Success!" in the science madness library.
Nitroacetic acid is fairly toxic, if I remember correctly. In any case, there are other better described routes to nitroacetic acid than your proposed
method from glycine.
[Edited on 2-11-2011 by AndersHoveland]
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Sedit
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The reduction problem could be solved using a cell divider. Even if there are other ways to Nitroacetic acid(I would love to see them) it would still
be of great value to be able to do this with various amino acids. Various energetic and biologically important materials as well as other precursors
could be developed rather cheep and easy. Solvents like Ethylene Diamine could be produced easy as well. The possibilities are almost endless if amino
acids could be Kolbe coupled without the great losses normally associated with electron donating groups being in the alpha position to the carboxylic
acid.
The main product would be ethane but that's no problem since NaOAc is so cheep the large excess wasted as Ethane would not be an issue considering the
side product of Nitroethane would be so much more valuable then NaOAc.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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