Polverone
Now celebrating 21 years of madness
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Guanidine
There's a well-known <A HREF="http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV1P0302">synthesis</A> of guanidine
nitrate from <A HREF="http://www.sciencemadness.org/talk/viewthread.php?tid=825">calcium cyanamide</A> and ammonium nitrate.
Disadvantages: possibly hazardous, and depending on what part of the world you live in, calcium cyanamide and/or ammonium nitrate may not be readily
available.
From discussion on the E&W Forum and <A
HREF="http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=
50&s1=4,535,185.WKU.&OS=PN/4,535,185&RS=PN/4,535,185">US Patent 4535185</A> I learned that guanidine nitrate could be
produced with a silica gel catalyst, urea, and ammonium nitrate. However, VasiaPupkin provided personal testimony that this method can be hazardous
(leading to explosions).
A few weeks ago, I read an interesting article in the Journal of Applied Chemistry of the USSR, and remembered enough of it for a few hours to e-mail
the following to myself:
"Best results found from heating 1:1:1 weight ratios of NH4NO3, silica gel,
and urea to 190 degrees for 2 hours. Best results with large surface area,
large pore size silica gel catalysts. Ammonium carbonate, phosphate,
sulfate did not work, but chloride and bromide did (with reduced yields).
Result from some 1959 or 1960 volume of Journal of Applied Chem USSR"
I want to say that yields with ammonium chloride and bromide were in the 25% range. That's not spectacular, but all of the materials are very
inexpensive, no special equipment is needed, and there is no danger of explosion as with other methods. Obviously, substitution will result in
guanidine salts of hydrochloric or hydrobromic rather than nitric acid.
PGP Key and corresponding e-mail address
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chemoleo
Biochemicus Energeticus
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Although it's very interesting (it really is), I happen to have GdnHCl in bulk. Apart from making GdnHNO3, what other uses are there? There got
to be many!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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guaguanco
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You can make a lot of heterocyclic chemicals with guanidine:
guanidine + 2,4 pentanedione -> 1-amino 3,5- dimethyl pyrimidine
guanidine + ethyl acetoacetate -> 1-amino 3-hydroxy 5-methyl pyrimidine
guanidine + bromoacetone -> 1-amino 3-methyl imidazole
etc etc
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Rosco Bodine
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safer method for guanidine nitrate
Here's a method which proceeds at mild temperatures
in the presence of water and also provides high yield .
Attachment: US2230827 Guanidine Nitrate via Cyanamide and NH4NO3 in H2O.pdf (328kB)
This file has been downloaded 2276 times
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DrP
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I wrote to and phoned a chinease company and they sent me a sample of natural guanidine powder in the post. Basically - it was a bag of powdered sea
bird shit! 
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Sobrero
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Natural grade indeed
@Rosco Bodine: that's the synthesis I have followed to make my batch of guanidine nitrate. High yields indeed and very safe compared to other routes
and very OTC for me (I bought technical (56%) calcium cyanamide and ammonium nitrate as fertilizers in a nearby horticulture/agriculture centre).
"There exists a world. In terms of probability, this borders on the impossible." (Jostein Gaarder)
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Rosco Bodine
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urea can also be added to reduce the reaction temperature
An improvement was claimed by a subsequent patent
US2431301 ( attached ) which relates to the same
reaction of Calcium Cyanamide with Ammonium Nitrate
to produce Guanidine Nitrate , using an addition of urea
in ~15% proportion to the Ammonium Nitrate for the purpose
of lowering its melting point , as an alternative to the use of
water for that purpose of obtaining a more easily fusible mixture . From the more anhydrous mixture a higher purity
product is supposed to be obtained in higher yield .
From what I have read about these calcium cyanamide processes , these reactions proceed well even using the
commercial fertilizer grade material which may be only perhaps half actual calcium cyanamide , so these processes
should proceed even better using a high purity calcium cyanamide as would be obtained from pyrolysis of calcium acid cyanurate .
These cyanamide , guanidine related threads are important
in their relevance also to the tetrazole thread .
Attachment: US2431301 Guanidine Nitrate via Calcium Cyanamide and Ammonium Nitrate - Urea melt.pdf (354kB)
This file has been downloaded 1711 times
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Axt
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Historical paper on the extraction of guanine from guano and oxidation to guanidine. Guano is available here as a fertiliser. Its in german so I'm not
real sure what details they go into and I assume 'guano' comes in various grades so the practicality of this is questionable. Though is interesting.
Attachment: guano to guanidine.pdf (599kB)
This file has been downloaded 1717 times
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Organikum
resurrected
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Excerpt/translation from the paper posted by Axt, part one, the extraction of guanine from guano:
Preparation of guanine:
He says this is easily done by the method described by Unger, cooking guano with milk of lime.
But he found it advantageous to modify the procedure in the following way:
Guano is dispersed in water, milk of lime is added in portions and this is brought to a boil and the resulting brown solution is filtered through a
pointed bag of cloth. This repeated as long the liquid takes on color.
This removes large amounts of ammonia, acids and other compounds (including urea nitrate and a counpound related to xanthine). Guanine and ureic acid
are the residue.
This residue is then repeatedly extracted with boiling sodium carbonate solution as long as addition of HCl produces a fallout.
To the joined extracts first sodium actetate and then HCl is added until strongly acidic. Guanine and urea precipitate out of solution. The residue is
washed with water and treated with slightly diluted boiling HCl and the ureic acid is filtered out. The filtered solution is boiled down for
crystallisation to yield guanine which still contains considerable amounts of ureic acid.
From this guanidin is separated by means of boiling hot diluted ammoniawater, it is then dissolved in boiling hot concentrated nitric acid waht
destroys the last ureic acid.
On cooling pure yellowish crystals of guanine nitrate precipitate.
Guanine is prepared form the nitrate by treatment with concentrated ammonia water, the product is only slightly yellow and used as is in the following
experiments.
Oxidation comes when I have time again.
/ORG
[Edited on 22-6-2007 by Organikum]
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AndersHoveland
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Guanidine from Urea
By heating urea, ammonium chloride, and aluminum sulfate together with ammonia under pressure, guanidine can be obtained. The reaction products are
boiled with an ammonium hydroxide solution to precipitate out the aluminum hydroxide. The remaining clear filtrate contains guanidine hydrochloride,
ammonium sulfate, unreacted urea, and unreacted ammonium chloride. Using equimolar ammounts of NH4Cl and urea, with one third of a mole aluminum
sulfate for every mole of urea, heated to 275degC, and subjected to 6.8 atmospheres of pressure, the yield of guanidine (relative to initial urea) was
28% after 30 minutes, and 34% after two hours. Using excess NH4Cl increased the yields further.
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clearly_not_atara
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A thought: since it seems like non-coordinating anions work better for the urea method, maybe ammonium hexachlorostannate is worth a look? This salt
precipitates readily from water and is non-hygroscopic.
https://www.prepchem.com/synthesis-of-ammonium-hexachlorosta...
I think the "ammonia under pressure" method sounds interesting but maybe not so easy to set up?
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clearly_not_atara
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Found one:
https://patents.google.com/patent/US2464247A/en
A mixture of 300 g. of urea and 1140 g. of ammonium sulfamate was fusedin an oil bath to provide a clear melt at a temperature of about 90 C.
Thereafter, the temperature was Bradually raised to 225 C. with no appreciable amount of decomposition, i. e., there was no evolution of gas. At the
aforementioned 225", C. a rapid exothermic reaction began to occur so that despite removal of the heat source the temperature of the reaction mixture
rose to 245 C. After about 30 minutes the reaction mixture had set up to a solid mass and the reaction was apparently over. The solid was then cooled,
ground and leached with water to obtain 388 g. of guandine sulfate of 70% of theory.
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