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maxidastier
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Well, actually, there are a few more things, that need to be updated, nice work anyway Engager, but:
http://www.patentstorm.us/patents/4390726/description.html
This patent is my favourite and it talks about how difficult it is to regenrate that silica gel.
They say, it has to be vacuum dried at over 200°C to convert all byproducts into gas.
So I would be interested in how you regnerated your silica gel and how often, be honest, you could use it again working smoothly. Because the water
you used won't actually do the job.
Reading it is better, but to sum it up: the catalyst has to be molten in pure Ammonium Nitrate with up to 20% urea to "drive the byproducts aways from
the catalyst into the slurry" 3x times.
Then you have to drie it at 30 torr and 80°C and then at 200°C to remove byproducts.
I died it at normal pressure in my oven. At least I got a clean cataylyst with a clean, shiny surface mostly free of byproducts.
Sry, I have to add another point: You say: 340g of ammonium nitrate (Note #2), 200g urea and 80g of tempered dry silica gel
The patent says: urea:AN 1:2, because this is the best method to avoid byproducts.
So it would be e.g. 120 g:240 g. Because convertion to Guanidinitrate at the beginning of the reaction is higher, after an hour on has to add 20 g
urea to keep the 2:1 ratio.
At the end of 3,5-4,5 hours reaction the ratio will change to 1:6, urea stopping to be converted.
So you have alot of AN to reuse or to slurry it with the catalyst.
Another point is the preparation of Nitroguanidin which you claim to be finished in ca. 15 mins.
A description I read says, it needs to be aged at least 15 hours to convert all Guanidinitrate.
I tried both ways and strongly recommend to age your mix at least 8 hours (over night).
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Engager
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Quote: Originally posted by maxidastier  |
Sry, I have to add another point: You say: 340g of ammonium nitrate (Note #2), 200g urea and 80g of tempered dry silica gel
The patent says: urea:AN 1:2, because this is the best method to avoid byproducts.
So it would be e.g. 120 g:240 g. Because convertion to Guanidinitrate at the beginning of the reaction is higher, after an hour on has to add 20 g
urea to keep the 2:1 ratio.
At the end of 3,5-4,5 hours reaction the ratio will change to 1:6, urea stopping to be converted.
So you have alot of AN to reuse or to slurry it with the catalyst. |
It may be that process described in patent may be better, please try it - if you will find your method more advantageous - it will be only better.
Personally i see ratio mentioned in my article as a good idea since worse F/O ratio lowers explosion hazard.
Regarding regeneration of catalyst - personally i never used it so many times, since procedure was tested extensively by my friend from Russian forum
- guy who is actually mentioned as second author of article. I trust him in his experience with this catalyst and trust other members of our community
who tried it, so i take possibility of regeneration as experimental fact.
| Quote: Originally posted by maxidastier |
Another point is the preparation of Nitroguanidin which you claim to be finished in ca. 15 mins.
A description I read says, it needs to be aged at least 15 hours to convert all Guanidinitrate.
I tried both ways and strongly recommend to age your mix at least 8 hours (over night).
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Timings of aging in H2SO4 are widely described in explosive related literature and found to be appropriate on practice. Watch this:
This is actually from Russian book on chemistry and technology of high explosives and it says that at 30C 10 min is ideal timing, while higher
temperatures and longer time causes increased decomposition of nitroguanidine.
[Edited on 29-7-2010 by Engager]
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maxidastier
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Well, actually I tried both aging times with the same amounts and got better results when agin more hours.
Decomposition of Nitroguanidin starts only after 20 hours as says this source:
http://www.lambdasyn.org/synfiles/nitroguanidin.htm
Another route to Guanidinitrate is the melting from Ammonium Nitrate and calcium cyanamide, both readily availabe fertilizers WITHOUT any catalyst at
even better yields.
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Engager
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Calcium cyanamide is not readily available in many countries, for example here in Russia mass production of cyanamide was stopped many years ago and
chemical is actually banned one. If you can get your hands on calcium cyanamide it can be converted to aminoguanidine in single step by reaction with
hydrazine sulphate or to 5-ATZ by reaction with hydrogen azide. I know this route for a long time and some people tried it, production of calcium
cyanamide require access to high temperatures, but source products are very cheap - urea and lime. I was experimenting with cyanamide production for
quite a while and will post article on this route some time soon.
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Engager
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Engager
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| Quote: Originally posted by Taoiseach | @497
There's several problems: Reducing 100g NQ would take over 40h at 5 amps. Higher currents are possible but they're operating at quite high a voltage
(to overcome additional resistance of the diaphragm I guess) which produces considerable heat. The 300A cell was operated with active cooling.
Temperature has to be kept below 30°C otherwise only nitrosoguanidine is formed. The best yield is obtained at 5°C cell temp. At such temperature
solubility of NQ is neglible (only 4.4g dissolve in 1000cc water at 25°C) This is probably why they're using rotating electrodes. Near the cathode,
concentration of NQ will drop due to reduction to well soluble aminoguanidine. The rotation helps to quickly supply NQ and minimize the gradient in
concentration.
I dont see how such electrodes could be improvised easily.
[Edited on 26-10-2009 by Taoiseach] |
Industrial Electric reduction of nitroguanidine is described in following paper:
PROCESS for AMINOGUANIDINE
R. Norris Shreve and R. P. Carter
PURDUE UNIVERSITY, LAFAYETTE, IND.
It's attached to this message.
Attachment: ie50413a015.pdf (260kB)
This file has been downloaded 3163 times
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Rosco Bodine
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| Quote: Originally posted by Engager | | Calcium cyanamide is not readily available in many countries, for example here in Russia mass production of cyanamide was stopped many years ago and
chemical is actually banned one. If you can get your hands on calcium cyanamide it can be converted to aminoguanidine in single step by reaction with
hydrazine sulphate or to 5-ATZ by reaction with hydrogen azide. I know this route for a long time and some people tried it, production of calcium
cyanamide require access to high temperatures, but source products are very cheap - urea and lime. I was experimenting with cyanamide production for
quite a while and will post article on this route some time soon. |
It can be inconvenient if there is a need for a banned chemical 
It may be possible to use any guanidine salt and react with hydrazine sulfate in corresponding molar proportion to produce either mono aminoguanidine,
di-aminoguanidine, or tri-aminoguanidine derivatives. The reaction is similar to the reaction of nitroguanidine with hydrazine to produce
nitroaminoguanidine. The mechanism is mentioned in a patent primarily related to production of triaminoguanidine salts. I will have to look it up,
but it is posted in the tetrazole thread.
Your interest regarding cyanamide is parallel to some isolated discussions which were taking place here, about experiments for producing pure calcium
cyanamide to be used for synthesis of guanidine and aminoguanidine derivatives including tetrazoles. Calcium cyanurate can be thermally decomposed
in the absence of air, by moderately high temperature, a low red heat, to produce 100% pure calcium cyanamide as the result. The precursor is easily
made by precipitation from calcium chloride solution and sodium cyanurate. Cyanuric acid is available as a chlorine stabilizer for swimming pools,
or may be easily synthesized from heating together urea and ammonium chloride. Alternately, reaction between urea and ammonium chloride at different
temperature and in the presence of silica gel catalyst produces guanidine hydrochloride instead, and this involves no explosive danger as would occur
with ammonium nitrate conversion to guanidine nitrate. The guanidine nitrate can (probably) subsequently be gotten from the guanidine hydrochloride,
via double decomposition. Certainly guanidine perchlorate can be gotten easily enough from double decomposition of guanidine hydrochloride and sodium
perchlorate, or probably from sodium perchlorate formed in situ from a basification of ammonium perchlorate with sodium hydroxide or sodium
bicarbonate, with boiling away of the ammonia. Guanidine perchlorate should nicely crystallize out from the residual byproduct sodium chloride
solution.
These interesting materials and methods certainly make urea an interesting subject for experiments. Attached are a couple of relevant patents.
Attachment: US2783276_SUBSTITUTED_GUANIDINE_SALTS.pdf (129kB)
This file has been downloaded 1976 times
Attachment: US2527316 Cyanuric Acid via Urea and Ammonium Chloride.pdf (129kB)
This file has been downloaded 1071 times
[Edited on 3-8-2010 by Rosco Bodine]
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Polverone
Now celebrating 21 years of madness
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Thread Split
3-8-2010 at 14:22 |
maxidastier
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I'm only interested in the step of producing Guaninidinitrate and further Nitroguanidin.
Is there another thread?
In Germany we have tons of Calcium Cyanamide as fertilizer. Strange, that many countires have banned it, because Germany is one of the "TOP" countries
to ban chemicals...
[Edited on 11-8-2010 by maxidastier]
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