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Decomposing Formamides
Anyone have tried acidic hydrolysis of formamides. I was wondering if hydrochloric acid was used would it decompose the formic acid formed into
carbon dioxide and form an aqueous amine salt solution ? Thanks.
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Metacelsus
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Are you talking about dehydration to carbon monoxide, or dehydrogenation to carbon dioxide?
Hydrochloric acid won't cause dehydration (or dehydrogenation), but it could cause hydrolysis.
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Quote By garage chemist,,Now that I think of it, dont use HCl, it would catalyze the decomposition of the formic acid into carbon monoxide,
especially when heated. That would be really bad if one did this outside of the fume hood and then thought "hey, whats that fizzing, that reaction
wasnt supposed to produce any gas..."
If the hydrolysis reaction is acid promoted using hydrochloric acid then the formic acid formed will be decomposed to carbon monoxide. Leaving an
amine salt, is this line on thinking correct?
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AJKOER
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Try attacking your formamide with hydroxyl radicals. See http://pubs.acs.org/doi/abs/10.1021/ja00716a011 as a source and listing of expected products. Per the reference, I would expect that the two cited
products are formed as follows:
HCONH2 + ·OH -----) H2O + HCONH·
HCONH2 + ·OH-----) H2O + CONH2·
which is apparently a hydrogen abstraction at both ends of the formamide molecule. Also, in the presence of oxygen (or oxygen source) additional
oxidation reactions could occur.
There are many ways of generating the OH radicals. One effect manner is by adding N2O, water and exposure to sunlight. Another is similarly by the
action of uv on H2O2, but such a reaction here may be more complex owing to direct oxidation reactions ocurring with the hydrogen peroxide as well
(where small amounts of H2O2 could form by the direct combination of two OH radicals). Even aqueous suspensions of TiO2 or Fe(OH)3 together with
sunlight may work as a source of hydroxyl radicals.
Note, the issue with this method is that there can be successive stages of intermediates being decomposed by the OH radicals, along with possible
oxidation in the presence of oxygen, with an occasional addition type reaction as well. So expect quite a list of possible (and toxic) products.
Various methods for the integration of the the OH radical for pollution remediation have proposed due to its effectiveness in breaking down organic
matter. See, for example, http://www.sciencedirect.com/science/article/pii/S0160412011...
[Edit] By the way, I very much suspect that the treatment of 95% C2H5OH, 5% H2O with N2O and a day of sunlight produces significant amounts of
hydroxyl and ethyl (or, more likely C2H5O) radicals. I believe so because a significant amount of heat treated Aluminum foil with a little sea salt
sitting in the mix (which also had an oxygen presence) managed to completely dissolve (more like vanished!) when left to stand for six hours after uv
exposure. The clear fluid when left to evaporate produced nearly no discernible residue!
[Edited on 3-8-2015 by AJKOER]
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Im trying to get together a formamide decomp. with hcl. aqu. or sulfuric . the goal is to reflux A formamide with 30 40 % hcl aqu. or 30 -35%
sulfuric to produce the aque. amine salt sol. For example simple formamide broken down to ammonia hcl or sulfate. This is not a amphetamine attempt .
I want to produce an amine salt sol. by simple den comp. of formamide,
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AvBaeyer
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Acidic hydrolysis of methylformamide and and dimethylformamide are easily done. I have done both to obtain methylamine hydrochloride and dimethylamine
hydrochloride. A typical example that I have done is as follows:
Dimethylformamide (29.2 gm, 0.4 mol) and 6M hydrochloric acid (100 ml) were heated at 95 C for 24 hr. The reaction was then set for distillation and
distilled until the head temperature reached about 120 C at which point some white fumes began to form. Most of the distillate came over from 103 -
108 C. As the pot cooled the contents quickly crystallized into a quite hard dimethylamine hydrochloride (34.42 gm, slightly greater than 100%). No
further attempt at purification was made as the compound as formed was suitable for the intended use.
The heating time was arbitrary. The reaction may not take nearly so long. I have hydrolyzed methylformamide in the same manner with similar results.
Give it a try and see how it works.
AvB
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Crowfjord
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I have done the exact same procedure as AvBaeyer outlines above, but with shorter heating time (about 1 hour, I think). Similar yields and
observations.
The dimethylamine HCl should be used or converted to a different salt quickly, as it is very deliquesent.
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Thanks for the outline, much appreciated. Have to get some things together and will attempt . Once again thanks mate.
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Like to thank AveBaeyer. I followed your outline applied it to 1-formylpyrrolidine 0.4M using 80ml 30% hydrochloric acid, 24hr reflux. Vacuum
distilled 60C at 25, distillate was 100ml. Pyrrolidine hlc was left in flask, weight was 0.39M, dam near 100%. Amine salt was treated w/ .4M sodium
hydroxide and pyrrolidine was observed .
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AvBaeyer
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Happy to have helped.
AvB
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