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Author: Subject: New Synthesis for Monomethyl (or higher) Amide?
AJKOER
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[*] posted on 28-10-2012 at 14:55
New Synthesis for Monomethyl (or higher) Amide?


Here is a possible new synthesis for CH3NH2 on which I would welcome comments. First, prepare Aluminum methoxide from Methanol and either Al or Al(OH)3. Per Wikipedia (http://en.wikipedia.org/wiki/Methanol#History ):

"Methanol, although a weak acid, attacks the oxide coating that normally protects the aluminum from corrosion:

6 CH3OH + Al2O3 → 2 Al(OCH3)3 + 3 H2O

The resulting methoxide salts are soluble in methanol, resulting in a clean aluminium surface, which is readily oxidized by dissolved oxygen. Also, the methanol can act as an oxidizer:

6 CH3OH + 2 Al → 2 Al(OCH3)3 + 3 H2 "

Next, prepare Monochloramine (NH2Cl), again per Wiki (http://en.wikipedia.org/wiki/NH2Cl ):

"NH2Cl is a highly unstable compound in concentrated form. Pure NH2Cl decomposes violently above −40 °C.[2] NH2Cl is, however, quite stable in dilute solution, and this considerable stability is the basis of its applications.
NH2Cl is prepared by the chemical reaction between ammonia and hypochlorous acid[3] under mildly alkaline conditions:

NH3 + HOCl → NH2Cl + H2O

The synthesis is conducted in dilute solution. In this reaction HOCl undergoes attack by the nucleophile NH3. At a lower pH, further chlorination occurs."

Now, the basis for the new synthesis is from the following reaction (source: http://www.pdfdocspace.com/docs/65323/nitrogen-containing-co... ):

"6. By action of chloramine on Grignard’s reagent:

(CH3)3CMgI + ClNH2= (CH3)3CNH2 + MgICl "

So what if one reacted Aluminum methoxide with Monochloramine, my initial reaction speculation:

Al(OCH3)3 + 3 NH2Cl = 3 CH3NH2 + Al(OCl)3

Now, the Aluminum hypochlorite could further decompose (releasing a precipitate of Al2O3) and the Monomethyl amide could also be further oxidized.

Or, the reaction could somehow proceed in the presence of CH3OH to form a Dimethyl ether amide (CH3OCH3NH2), as the Dimethyl ether is the simplest ether.

All in all, I suspect the reaction would be interesting although the reaction products are, at least in my humble mind, a bit uncertain.


[Edited on 28-10-2012 by AJKOER]
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12AX7
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[*] posted on 28-10-2012 at 15:32


Hmm, methoxides are methoxylating agents, not methylating. OCl simply isn't a leaving group, and there's no reason for it to form (think: that implies you could make bleach from chloramine, when the opposite is true at STP). More likely you'd get CH3ONH2, but this probably disproportionates or something, and still implies a byproduct of AlCl3 which is rather oxophilic.

Tim




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[*] posted on 28-10-2012 at 16:05


Detritus?
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AJKOER
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[*] posted on 28-10-2012 at 20:12


Actually, if you are correct, this could be very important reaction as to quote "methoxyamine (CH3ONH2), a potential new chemotherapeutic agent, in human and mouse plasma" (see http://www.ncbi.nlm.nih.gov/pubmed/14522034 ).

The reaction would then be:

Al(OCH3)3 + 3 NH2Cl = 3 CH3ONH2 + AlCl3

However, I disagree with 12AX7's statement " think: that implies you could make bleach from chloramine, when the opposite is true at STP)" as per this reference (http://www.researchgate.net/publication/12006087_Monochloram... ) the hydrolysis of NH2Cl is apparently reversible with further occurring reactions. For example, see Equations 1.1 and 1.2, to quote:

1.1 HOCl+NH3--> NH2Cl+H2O
1.2 NH2Cl+H2O --> HOCl+NH3
1.3 HOCl+NH2Cl --> NHCl2+H2O
1.4 NHCl2+H2O --> HOCl+NH2Cl
....

This also makes sense as the disinfectant properties of NH2Cl appear to be related to HOCl. Therefore, one could argue there is a link between OCl and NH2Cl, which I think contradicts your argument (although I hope not, given what the compound is, a new chemotherapeutic agent, and a possibly new low cost synthesis thereof, proposed on Sciencemadness no less).

[EDIT] To be more detailed, assume an aqueous medium and replace the reversible NH2Cl + H2O with HOCl + NH3, then the reaction can be rewritten as:

Al(OCH3)3 + 3 [HOCl + NH3] = ...

Now, if:

Al(OCH3)3 + 3 HOCl = Al(ClO)3 + 3 CH3OH

any Aluminum hypochlorite created would be quickly attacked by the ammonia (and given the formation of an insoluble Aluminum hydroxide, perhaps a good path to preparing Chloramine in general):

Al(ClO)3 + 3 NH3 = 3 NH2Cl + Al(OH)3 (s)

which would leave Chloramine and Methanol to react (or not depending on concentration and time exposure, I would guess). Now, if they did react, the only possible path to CH3NH2 (which was my original supposition) is:

NH2Cl + CH3OH =?= CH3NH2 + HOCl

which could be a reversible reaction also, but a catalyst (Fe, CuO,..) introduced at this point may be able to decompose the Hypochlorous acid moving the reaction to the right.


[Edited on 29-10-2012 by AJKOER]
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AJKOER
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[*] posted on 29-10-2012 at 06:59


My lack of confident on the Aluminum methoxide and Monochloramine reaction may be appropriate after reading the discussion at http://archive.reefcentral.com/forums/archive/index.php/t-25... between Amquel (hydroxymethanesulfonte) and chloramine. That thread appears to set a new bar in confusion with respect to a Chloramine reaction.

There is also a referenced Patent 4,666,610 (http://www.google.de/patents/US4666610 ) and a description of how, reputedly, Amquel works at http://aquabaz.tripod.com/amquel1.htm.
------------------------------------------------------------

Safety Warning: There are reported cases of where Chloramine can potentiate the poisonous effects of Chloromethane producing blindness. As CH3Cl on hydrolysis forms CH3OH in the body, I would expect NH2Cl would also potentiate the effects of CH3OH vapors, so take appropriate safety precautions especially with respect to eye exposure.


[Edited on 29-10-2012 by AJKOER]
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[*] posted on 29-10-2012 at 13:50


Quote: Originally posted by AJKOER  
[EDIT] To be more detailed, assume an aqueous medium and replace the reversible NH2Cl + H2O with HOCl + NH3, then the reaction can be rewritten as:

Al(OCH3)3 + 3 [HOCl + NH3] = ...

Now, if:

Al(OCH3)3 + 3 HOCl = Al(ClO)3 + 3 CH3OH


Funny guy. Planning a reaction with knowledge from Wikipedia is not a good starting point.

Your first reaction with the Al(OMe)3, HOCl and NH3 you will need a basic, oxidizing aqueorous solution where the Al(OMe)3 will decompose immediately, so the whole writeup won't work.




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[*] posted on 30-10-2012 at 09:46


Quote: Originally posted by kristofvagyok  
Funny guy. Planning a reaction with knowledge from Wikipedia is not a good starting point.



Madcap schemes that involve 'HOCl' and are never tried or tested are AJ's signature.




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[*] posted on 30-10-2012 at 17:38


With respect to the Wiki opinion on the reaction between Aluminum and Methanol, here is another good source (see page 38 at http://books.google.com/books?id=iEeiQEeLOmYC&pg=PA38&am... ) that notes that the reaction is more rapid in anhydrous CH3OH as even very small amounts of water slow the reaction. This basically confirms the validity of the Wiki reaction. As such, I would expect the following hydrolysis:

Al(OCH3)3 + 3 H2O = Al(OH)3 + 3 CH3OH

which could deposit a protective layer of Al(OH)3 on Aluminum slowing its dissolution in methanol.

With respect to the importance and role of HOCl in many organic synthesis please see page 555 at http://www.scribd.com/doc/30121142/Dichlorine-Monoxide-Hypoc... .

For the record, I am not necessarily insisting that the reaction between NH2Cl and Al(OCH3)3 be conducted in a dilute aqueous medium (perhaps in CH3OH).


[Edited on 1-11-2012 by AJKOER]
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[*] posted on 2-3-2014 at 10:56


Quote: Originally posted by 12AX7  
Hmm, methoxides are methoxylating agents, not methylating. OCl simply isn't a leaving group, and there's no reason for it to form (think: that implies you could make bleach from chloramine, when the opposite is true at STP). More likely you'd get CH3ONH2, but this probably disproportionates or something, and still implies a byproduct of AlCl3 which is rather oxophilic.

Tim


Quote: Originally posted by AJKOER  
Actually, if you are correct, this could be very important reaction as to quote "methoxyamine (CH3ONH2), a potential new chemotherapeutic agent, in human and mouse plasma" (see http://www.ncbi.nlm.nih.gov/pubmed/14522034 ).

The reaction would then be:

Al(OCH3)3 + 3 NH2Cl = 3 CH3ONH2 + AlCl3

.....


I happen to stumble across an apparently good source "Amines: Synthesis, Properties and Applications", by Stephen A. Lawrence, page 174, at http://books.google.com/books?id=35xwBwjhe2MC&pg=PA172&a... ). To quote:

"Chloramine reacts with alkoxides to form hydroxylamines.

RONa + NH2Cl --> RO-NH2 + NaCl "

So, the formation of Methoxyamine (CH3ONH2) may be possible per the reaction:

Al(OCH3)3 + 3 NH2Cl --> 3 CH3ONH2 + AlCl3

although, I agree, that the AlCl3 byproduct, being rather oxophilic, may be problematic.

Per the same source, also a new way to form a stable (gas phase) form of NH2Cl, which one may be able to use directly in the above reaction. Namely, on page 172 the author cites the direct action of ammonia on Cl2 gas, with only a slight stoichiometric excess of the NH3:

2 NH3 (g) + Cl2 (g) --> NH2Cl (g) + NH4Cl (s)

and removing any excess ammonia by passing the product gases over anhydrous CuSO4.
-----------------------------------------------

Some words of caution on Monochloramine, per the author the gas phase is described as stable, but I believe Wikipedia is accurate here (see http://en.wikipedia.org/wiki/NH2Cl ) when, to quote:

"NH2Cl is a highly unstable compound in concentrated form."

So, per the cited direct synthesis above, I would recommend the use of a dilutant inert gas, and also avoid moisture as:

NH2Cl (g)+ H2O (vapor) = NH3 + HOCl (vapor)

and as: 2 HOCl = Cl2O + H2O

and, in concentrated conditions, the Hypochlorous acid equilibrium moves to free dichlorine monoxide. The potential problem, in my opinion, is that free Cl2O could explode on contact with NH3, as it is known to do (see "Comprehensive Guide to the Hazardous Properties of Chemical Substances", by Pradyot Patnaik, page 477 at http://books.google.com/books?id=-CRRJBVv5d0C&pg=PA476&a... ).

[Edited on 2-3-2014 by AJKOER]
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[*] posted on 2-3-2014 at 19:13


Aluminum methoxide will not react like an alkali metal methoxide as it posseses little ionic character - the methoxide-aluminum bond is mostly covalent. I doubt that aluminum methoxide has much practical synthetic utility. There is no reference to it in Fieser and Fieser "Reagents for Organic Synthesis" in the collective index for vol 1- 12.
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[*] posted on 3-3-2014 at 05:29


Also, the Al(MeO)3 is likely formed by boiling anhydrous AlCl3 with an excess anhydrous MeOH:

AlCl3(s) + 3 MeOH(l) < === > Al(MeO)3(solvated) + 3 HCl(g), driven to the right by the volatility of HCl. Evaporation of the excess MeOH would leave the Al methoxide.

The action of MeOH on Al(OH)3 or Al2O3 is likely to create a worthless mess.

[Edited on 3-3-2014 by blogfast25]




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[*] posted on 3-3-2014 at 05:43


Forgive me if I misinterpretted your post, but that seems like a pretty uneconomical route(given how difficult anhydrous AlCl3 is to procure/prepare.)

Can you not simply use the same method with which Aluminium isoproproxide is synthesized? Al + Hg salt + Alcohol = Al alkoxide?
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[*] posted on 3-3-2014 at 10:00


Quote: Originally posted by Mesa  
Can you not simply use the same method with which Aluminium isoproproxide is synthesized? Al + Hg salt + Alcohol = Al alkoxide?


Possibly but are Hg salts cheap/easy to obtain?

Do you have a reference for this method?




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[*] posted on 3-3-2014 at 10:00


Quote: Originally posted by Mesa  
Can you not simply use the same method with which Aluminium isoproproxide is synthesized? Al + Hg salt + Alcohol = Al alkoxide?


Possibly but are Hg salts cheap/easy to obtain?

Do you have a reference for this method?




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[*] posted on 17-7-2014 at 05:52


Al + Ga + R-OH = Al-OR + Ga + H2

Gallium is not cheap (GBP 50 for 90grams) but it is not consumed.

I made Aluminium Triethoxide yesterday using this simple procedure. The reaction is remarkably vigorous even at room temperature.
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