Author Topic: MeNH2 from Sulfamic acid and MeOH  (Read 220 times)

Sedit

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MeNH2 from Sulfamic acid and MeOH
« on: December 05, 2009, 12:26:35 AM »
Materials:
MeOH
Sulfamic acid - avalible as a septic restorer, Tile cleaner, and coffeemaker cleaner amongst other things.
Drying tube of some sorts.

Procedure:

Add 100ml MeOH and 50 grams of Sulfamic acid.
Reflux until Sulfamic acid is consumed[note 1]

What happens next is whats knows as a solvolysis reaction where the reagents react with the solvent to produce a given compound.

The solvolysis reaction was pretty uneventful but it took quite a while without stirring leading to a medium reflux for 6 hours or so before all the sulfamic acid was consumed. At first it appeared that no reaction was taking place but after a while it started to become obvious that the Sulfamic acid was slowly being digested until there was nothing left but a slightly yellow colored alcoholic solution. This yellow color is more then likely due to contamination but others have since confirmed the same thing so perhaps its due to impure reagents and not dirty condenser like I originaly believed.

After it completed I decided to distill the remaining MeOH out which I did recovering 50ml of Methyl alcohol before very little would come over but no doubt trace amounts where left in the post reaction mixture. The distillation of the MeOH was a bit unusual as not once did the contents ever boil. Not even a bubble just a slow steady drip of MeOH out of the condenser.

After slow cooling I expected to see the pearlescent crystals of Ammonia methylsulfate but instead the mixture stayed a liquid even 2 hours after turning the heat off. I decided to pick the flask up to see if any crystal formation has occured and instantly the whole of the liquid solidified into long pearly crystal mass that looked just like Sodium acetate "hot ice" experiments. It honestly looked pretty fucking cool but caught me off gaurd because all I could think was, "Why the fuck aint this crystalizing" and the in 2 or three seconds the whole mess was solid.

Now its just a matter of placing the flask on a hot plate and slowly raise the temperature to 220-230C for a little while until the isomerization is complete. The text stated that above 240C the production of ethylene became more appearent and that they only did 15 minute rearrangment test inorder to prove that heat played more of a factor then time in the isomerization. I suggest to push the heat up a little higher and force the isomerization which happens in almost quantative yeilds.

Workup:

Further purification will be to slowly drip a saturated NaOH solution into the hydrosulfate salt and feed the out gassing product into Muratic acid to yeild the cleaned MeNH2*HCl. [note2]

Discussion:

What is taking place here is that Sulfamic acid is reacting with the MeOH forming a compound call Ammonia Methyl Sulfate or NH3*MeSO4. This undergoes isomerization at higher temperatures to yeild a compound MeNH2*HSO4 also known as Methylamine Bisulfate. I will attach a paper confirming all this thru peer reviewed text. I post this in hopes that someone here will get a little bit better understanding on the production of Ammonia ethylsulfate for Nitroethane synthesis which arises from subsitution of MeOH with EtOH.

Notes

1: Excess Alcohol is desireble if one wants the reaction to proceed at an increased rate.
2: This proved problematic but im sure someone skilled in the art could do it. Someone else that confirmed this reaction stated to base the Methylamine Bisulfate and pass the gas thru a condenser at -15 degrees into an alcoholic solution. This would allow titration if desired much better then guessing and wasting much gassious methylamine thru bubbling into HCl solution does making your whole are smell of a french whore if you fuck up.
3: Products are highly hygroscopic so store with care or they will turn liquid in a matter of hours.

!IMPORTANT!
The Reaction must be performed under Anhydrous conditions.

Sulfamic acid undergoes hydrolysis in the presents of H2O. A drying tube where as Not 100% sure its needed IMHO should be used.
« Last Edit: December 05, 2009, 02:55:13 AM by Sedit »
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Benzene

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Re: MeNH2 from Sulfamic acid and MeOH
« Reply #1 on: December 08, 2009, 03:16:36 AM »
According to the book “The Organic Chemistry of Sulfur Tetracovalent Sufur Compounds” by Chester Merle Suter, only 27% methylamine can be obtain by the rearrangement of Ammonia Methyl Sulfate.  It also states that ethyl, n-proply and isobutyl ammonium sulfates do not rearrange to amine salts, the olefins being involved instead.

Sedit

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Re: MeNH2 from Sulfamic acid and MeOH
« Reply #2 on: December 08, 2009, 11:58:57 PM »
Sorry I thought I had attached this. Regardless of what that text states its more then likely due to low temperatures(although im not sure I have read it). If you read Table II in the attached text you will see that 276 degrees C the isomerization is 97.8% in 15 minutes. Higher temperatures are prefered but to high and Ethane formation starts to become a problem. They stated 15 minutes just to prove that temperature has more to do then reaction time so perhaps it would be better to run it for a longer then 15 minutes.
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Benzene

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Re: MeNH2 from Sulfamic acid and MeOH
« Reply #3 on: December 11, 2009, 10:40:15 PM »
Sedit, the article that you posted was mention in the book "Organic Chemistry of Sulfur Compounds".  However the book states that “later workers found the product of the reaction to be a mixture of the salts of the three methylamines, the maximum yield of methylamine obtainable being only 27% of the theoretical amount.  See J. Chem. Soc., 117, 236 (1920). 

Enkidu

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Re: MeNH2 from Sulfamic acid and MeOH
« Reply #4 on: December 11, 2009, 10:46:14 PM »
the product of the reaction to be a mixture of the salts of the three methylamines, the maximum yield of methylamine obtainable being only 27%

The three methylamines are mono, di, and trimethylamine? or what?

Sedit

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Re: MeNH2 from Sulfamic acid and MeOH
« Reply #5 on: December 13, 2009, 06:07:22 PM »
Can you by any chance upload that book here or provide a link? I really want to see it.
There once were some bees and you took all there stuff!
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Benzene

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Re: MeNH2 from Sulfamic acid and MeOH
« Reply #6 on: December 16, 2009, 03:02:25 PM »
Here are 3 pages from the book.  Sorry I don't have time to scan all 858 pages.

Enkidu

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Re: MeNH2 from Sulfamic acid and MeOH
« Reply #7 on: December 16, 2009, 09:16:15 PM »
The preparation of methylamine from ammonium methyl sulphate
William Smith Denham and Lionel Frederick Knapp
J. Chem. Soc., Trans., 1920, 117, 236 - 247, DOI: 10.1039/CT9201700236