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angelhair
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Formic acid from Hexamine/HCl?
What percentage of formic acid could you reasonably expect to get from a methylamine reaction using Hex/HCl under a slight vacuum. Say about 250 torr.
Is it worth it?
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Klute
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Your product will be heavily contaminated with other products (noxious ones amongst others, chloromethyl ethers, formaldehyde, etc). Most of the
formic acid decomposes to CO2 anyway i think.
Really not worth it IMHO
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
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angelhair
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Thanks, I might look at oxalic acid and glycerol route that I saw in my old organic text book by Cohan. I don't think I spelt his name right.
In that synth they also use Lead formate and Hydrogen sulphide. I was under the impression that all you needed is the acid and glycerol.
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Klute
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Good luck getting a workable amount out of this reaction! it's very time consuming, and you get ~60% concentration at most. But it can be done if you
are willing to spend time on it.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
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chemrox
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Extract an ant colony.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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Axt
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Would the reaction of hexamine with H2O2 + NaOH produce Na formate? this seems to work where formaldehyde in in place of hexamine.
H2CO + H2O2 + 2NaOH --> 2HCOONa + 2H2O + H2
2HCOONa + aqueous H2SO4 --> 2HCOOH + Na2SO4
Regarding formic acid from oxalic acid, I just stuck a page up here http://homechemistry.org/index.php?title=Preparation_of_form... which I took out of a NTO writeup I half done a couple years ago but never found
the motivation to finish.
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Nicodem
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I also think the controlled oxidation of hexamine should lead to formate salts mainly. Even if it does not get oxidized directly, hexamine slowly
equilibrates with HCHO&NH3 anyway so it would just take more time. Though, I'm not sure if this equilibration is going on in basic media as well.
I guess it is worth a try.
As long as the bees don't get extinct, the beekeepers will use large amounts of formic acid to fight the Varoa mite infestations and thus formic acid
will remain fully OTC. You just have to know where to buy it. However, if the bees gets extinct we are fucked anyway and we will be more preoccupied
with food shortage rather than formic acid preparation.
PS: Since this thread appears more like about an alternative source for formic acid than an experiment out of curiosity and because the original
poster used no references, I'm moving it from Organic chemistry to Reagents and Apparatus Acquistion section.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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S.C. Wack
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The glycerol procedure works well enough but it is cheaper to buy formic of course. The concentration is not much of an issue for me as fractionation
works. The glycerol can be used again and again and I probably have a liter of such around somewhere.
There is also a procedure using cotton and HCl in place of glycerol, and a "concentration" procedure using aniline (the formanilide) to get 99% acid,
but these came too late for me to try as I just buy mostly now. So there's stuff out there waiting for the amateur to find and try.
Anyone tried refluxing chloroform with alcoholic NaOH for formate?
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Klute
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The haloform reaction would be a good source of formates, giving chloroform in the case of bleach.
I think 85% H3PO4 can be used to generate formic acid out of dried formate salts without the CO production conc. H2SO4 causes, but don't take my
word on it, I've never done it. I buy my formic acid like everybody else 
Nicodem, in France they are starting to limite formic acid use, making alot of beekeepers unhappy because it is described as a cheap and selectif
pesticide. I was unable to buy some from such outlets when i wa still looking for some there. Obviously, the pesticide-manufacturing firms prefer
selling new expensive pesticides, which are more expensive to make, so generate more work and especially money. Most of the firms actually work
for/are pharmaceutical companies, so they have got some reach. Sorry to disgress.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
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stoichiometric_steve
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| Quote: | Originally posted by S.C. Wack
Anyone tried refluxing chloroform with alcoholic NaOH for formate? |
you can use aqueous NaOH, this is exploited in the qualitative analysis of CHCl3.
are there ANY more expensive ways to formic acid?
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BromicAcid
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Klute, I think some clarification is in order:
| Quote: | | The haloform reaction would be a good source of formates, giving chloroform in the case of bleach. |
When most people think of the haloform reaction they think of the reaction of a methyl ketone to form the chloroform. The simplest ketone being
acetone some people would think the simplest carboxylate that could be produced would be acetate. However you, I, and some others know the haloform
reaction can also work on some alcohols, in this case ethanol, to give a haloform reaction. The conclusion being one molecule of haloform and another
of the formate. Just clearing that up for some of the others here.
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Picric-A
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cant you just buy it?
i buy 750ml of 85% formic acid as a drain cleaner.
it is reasonably pure as well. no colourants ect...
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Klute
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@Bromic Acid: yes, sorry for the mishap, I was obviously thinking of using bleach with either acetone or ethanol, forgot to precise it. Thank you for
the clarification 
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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smuv
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| Quote: | | When most people think of the haloform reaction they think of the reaction of a methyl ketone to form the chloroform. The simplest ketone being
acetone some people would think the simplest carboxylate that could be produced would be acetate. However you, I, and some others know the haloform
reaction can also work on some alcohols, in this case ethanol, to give a haloform reaction. The conclusion being one molecule of haloform and another
of the formate. Just clearing that up for some of the others here. |
While true, I just want to elaborate, so others understand what is going on; The haloform reaction only works methyl ketones and acetaldehyde. The
reason why ethanol seems to undergo the haloform reaction is because it is oxidized in situ by the hypochlorite to form acetaldehyde, which then
enters the haloform reaction; the same goes for isopropanol and other alkyl-2-ols which are oxidized to methyl ketones in situ. So I want to clear up
no alcohols undergo the haloform reaction; it is only their oxidation products which do.
[Back on topic] The Cannizzaro reaction is another possibility; although I am not so sure on the conditions, because basic formaldehyde solutions
usually yield a polyoxymethylene precipitate upon treatment with alkali hydroxides (although this does require gentle heating).
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kalacrow
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Formic acid preparation
| Quote: | Formic Acid[64-18-6]
(CHOOH)
[3] Mix an equal amount of glycerine and oxalic acid and place in a flask. Heat this mixture at 75-90°C. Continue heating until no more CO2 bubbles
out. Fresh oxalic acid is added and the process continued. When enough acid is made, distill it over using the proper apparatus and raising the
temperature with an oil bath. 90% formic acid is collected. Alternatively, you can place the mixture in a distillation apparatus with a vacuum
connection. Read the temperature with the thermometer placed into the mixture. Heat the mixture to ~90°C, but while under reduced pressure. As the
reaction proceeds the formic acid will distill over. This takes about 4 to 5 hours for 500g of glycerine and 500g of oxalic acid.
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oxalic acid is available as wood bleach. Check the "readily available chemicals" list.
[Edited on 23-5-2008 by kalacrow]
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MagicJigPipe
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| Quote: |
cant you just buy it?
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Not OTC in the US as far as I know. And I look for chemicals EVERYWHERE I go.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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Aqua_Fortis_100%
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Great page!! I just love the scheme/pic using a Wine Glass as receiver! Is a simple and very good idea to dont re-heat the formic causing a sort of
reflux inside the apparatus.. I will certainly try that for nitric acid.
Why dont use at least a part of the oxalic as anhydrous? This would cause a increase of % of the obtained formic(or no?).
BTW, by what means you made your semicarbazide hydrochloride for NTO synth? I have a great interest in your experiments, just damn cool and very
informative as well!
Rosco posted a patent in hydrazine thread and is that I have on my HD along with similair ones I've searched and that are based on monochlorourea
derivates, IIRC..
=======
| Quote: | Originally posted by S. C. Wack :
There is also a procedure using cotton and HCl in place of glycerol |
Please, S. C. Wack, what is that method and where I can find info about it? Yields, purity, etc?
Just seems interesting..At least in theory =]
=======
| Quote: | Originally posted by MagicJigPipe
| Quote: |
cant you just buy it?
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Not OTC in the US as far as I know. And I look for chemicals EVERYWHERE I go. |
Yes, here too.. Since the damn meth cook have grow their clandestine labs, the most fuc*ing lazy act of the authorities is just cut it off from OTC
and restric it to labs (to buy that (and H2SO4, HCl, acetone, Na2SO4, MEK, Ac2O, etc) here you need to show some personal documents and comprove your
location).
BTW, here the only OTC of thread related is oxalic, but just dont worth bothering to extract.. It comes in a small bottle of 50-100mL and is just 30%
solution and very expensive as well..
[Edited on 25-5-2008 by Aqua_Fortis_100%]
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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not_important
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Heating paraformaldehyde (polyoxymethylene) with boric acid under pressure gives a 75% yield of methyl formate:
Boric acid catalyzed Tishchenko reactions
Paul R. Stapp
pp 1433 - 1434; DOI: 10.1021/jo00947a049
note that the plastic known as Delrin or POM is polyoxymethylene with an endcap.
Passing methanol vapour over Cu, Ag, or copper chromite, the over a basic catalyst can do the same thing:
MeOH ==(Cu catalyst 400C)==> H2CO + H2
2 H2CO ==(catalyst)==> H3CO2CH (methyl format)
Not the most simply set of reactions, being heated tube ones requiring the preparation of the catalysts.
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S.C. Wack
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By request above, from JACS 53, 2700 (1931):
"80 g. of crystallized oxalic acid, 100 g. of absorbent cotton and 100 ml. of concentrated hydrochloric acid are required. The oxalic acid is melted
in its water of crystallization in a 1 L round-bottomed flask over the water-bath and the cotton, torn into small bits, thoroughly shaken with it. The
hydrochloric acid is added and the flask connected for steam distillation in the usual manner, the flask being supported on gauze and tripod and not
on the water-bath. Before the admission of steam, the flask is heated by the burner flame and kept boiling until about 50 ml. of distillate is
obtained. The distillate is returned to the flask, 100 ml. of water added and the mixture steam distilled until about 150 ml. of distillate is
collected.
Lead oxide is added to the distillate in slight excess and the liquid filtered. The filtered liquid is evaporated to small bulk and allowed to
crystallize. The yield is 65 g. of lead formate, equivalent to 20 g. of formic acid. If it is assumed that one mole of oxalic acid gives one mole of
cellulose mono formate and that the cellulose mono formate is completely converted to formic acid, it follows that one mole of oxalic acid in this
procedure should yield, theoretically, a maximum of one mole of formic acid. On this basis 126 g. of crystallized oxalic acid will give 46 g. of
formic acid. The theoretical yield of formic acid is therefore 27.2 g. If desired, the formic acid is recovered by dissolving the lead formate,
precipitating the lead with hydrogen sulfide and distilling off the formic acid."
The temperature for methyl formate production with copper chromite catalyst can be lower, 220C here though yields are not great.
Attachment: iecprd_23_384_1984.pdf (593kB)
This file has been downloaded 1925 times
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Aqua_Fortis_100%
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Thank you very much S. C. Wack.. Actually I misinterpreted what I have said
before "There is also a procedure using cotton and HCl in place of glycerol".. I was under the impression that just cotton and HCl should did
the job  Oxalic is still required in this preparation..
Anyways, thank you for that info, is very good to know other methods and can just be useful in near future, since for some reason the glycerin bottles
are disappearing on OTC stores/pharmacies that I usually spend a lot of time trying to find anything useful..
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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angelhair
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50-60% via Oxalic is low. I would like 70% at least. Other than distillation, what drying agent could possible used to get it up to 70%.
Also, for those of you that fractionate, how easy or difficult is it? What temp do you collect at?
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starman
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| Quote: | Originally posted by angelhair
50-60% via Oxalic is low. I would like 70% at least. Other than distillation, what drying agent could possible used to get it up to 70%.
Also, for those of you that fractionate, how easy or difficult is it? What temp do you collect at? |
I have played with the glycerol/oxalic route a fair bit.Make sure the glycerol is anhydrous,partially dehydrate the oxalic dihydrate to the
monohydrate(constant agitation and calculate the weight loss).
Careful control of the conditions can give you up to 75%.Store over anhydrous copper sulphate in large excess from several days to weeks,should give
you 87 - 88%
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Klute
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Surely you can substitute the formic acid if you need to go through so much trouble to get it? There isn't tons of reactions where formic acid is a
definate requirement...
For example, if you wanted to make some performic acid, peracetic or persulfuric acid are very good alternatives.
If you want formate salts for CTH, you can directly make them via a haloform, if you want to prepare formamides, you can use ethyl formate instead
(made from the formate salts in last resorts), etc
Preparing concentrated formic acid isn't such a trivial thing to do, better avoid it if you can.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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angelhair
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You make preparaing formic sound like a nightmare which makes me want to do it even more so. Surley it can't be any more untrivial than making
MeNH2.HCl?
Ignore my question about fractionating. I just realised that formic distills as an azeotrope.
How does peracetic acid perform in comparison to performic acid?
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Klute
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Well, not really a nightmare, but tedious work. MeNH2.HCl is actually even simplier, but just a bit long and smelly, but you obtain a butload of clean
product at the end, with needing to purify it an countless number of times. But of course there isn't any easy substituant!
Peracetic is just longer to prepare than performic. I must agree performic is very easy in the sense that you mix the acid an dH2O2 in the cold, and
you a ready to go, while with peracetic you have to wait 2-3 days with a little H2SO4, but that leaves you plenty of time to prepare things a head, do
a little cleaning, etc
Of course you can also prepare it from perborate if you have good stirring equipement, which is immediate, and apparently very smooth and selective.
Or depending on your application and substrate, using peroxodisulfate in AcOH/H2SO4 can be a very rewarding alternative, easy to prepare, no thick
slurry, and very satisfying yields.
Performic is very practical if you have a supply of 85% formic acid, but i really do not think it is that much better than other percaids to go
through the trouble of preparing a minute amount of dilute acid with lots of efforts.
The three days waiting with peracetic will be compensated by three days of work to obtain a decent amount of formic acid, and the two are perfectly
substituable IMHO. If you feel like trying out new procedures, the persulfuric method is very easy to employ, and I had very good results with it once
the optimal conditions where found.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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