AttiganDruga
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Registered: 16-5-2012
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Hydrolysis of hexamine to methylamine hcl, purification of product questions
Below is the reference I have used because I have access to Hexamine and it looks like it yields Methylamine HCl in near quantitative yields. Due to
the fact that I do not have access to chloroform I decided to use a slight excess of 31.45% HCl, 450mL to each 140 grams of Hexamine and allowed it to
react longer than was called for. I expect that methanol could be used to dissolve the Hexamine as well having looked up the solubility. But my main
question is would thus... If there is contamination present, and I do not see any reason there would be, if that contamination is a small amount of
Ammonia Chloride which I suspect may be a bi-product, would that harm a reductive alkalation reaction? I ask because the Ammonia Chloride is slightly
soluble in methanol so I so not think I have any way to totally purify it. I am grateful to anyone who has any critiques of my perhaps amateurish
logic or answers to my query. Below is reference I slightly modified as described above. I have completed the reaction but not yet moved on to the
purification of the product. Also, does it really need purification?
140 grams of Hexamine is carefully dissolved in 400mL of 31.45% HCl with vigorous stirring. After all is added, heat on the water bath. This will
drive off the formed Carbon Dioxide and then the excess water. The yield of Methylamine HCl is 270g, colourless to just barely white deliquescent
crystals. If the crystals are opaque white and do not deliquesce quickly in air of average humidity (65% rh) they may be contaminated with some
Hexamine. Washing 100 grams of the crude product with 100mL of Chloroform by stirring in a beaker then filtering, repeated as many times as necessary,
will remove Hexamine. Methylamine HCl is insoluble in Chloroform whereas Hexamine is at the rate of 1g to 10mL.
Synthesis, March 1979, Blazevic, "Hexamethylenetetramine, A Versatile Reagent in Organic Synthesis", pp161-176"
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zenosx
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Posts: 188
Registered: 7-7-2012
Location: East TN / Near Oak Ridge
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Mood: Awaiting Results....
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Hmm, I might try this myself. I don't have time to post the procedure I followed but it was similar to this, only the HCL was added slowly to prevent
an overage of Ammonium Chloride instead of the methylamine HCL.
I haven't had time, but if I do in fact get a yield of MeAmine HCL crystals from my synthesis I will post back here. (they are currently contained in
probably the 3rd fraction of a distillation using the synth I followed. Found it on erowid I believe.
I'll repost the exact method if I find time, and when I have time to workup the fractions sitting on my bench.
A question that sometimes drives me hazy: am I or are the others crazy?
Albert Einstein
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