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PHILOU Zrealone
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Out of PM with underground:
-QUOTE-
You should search in Freepatents Online or Google Patents...on the web.
There you can download pdfs files where there are a lot of informations.
I have searched a bit for you among a 30 number of patents about urea and biuret and I have found the most relevant to our case:
US4701555-Methods for removing biuret from urea by adsorption
US3184508A-Crystallization of biuret from biuret containing aqueous solutions saturated with urea
US3150177A-process for producing biuret
US2524049A-production of biuret
US2370065A-manufacture of biuret
US2145392A-preparation of biuret
-END OF QUOTE-
Based on those chosen patents and taking into account urea is cheap, the process is easy and separation between urea/biuret quite simple, even if
biuret is formed in 20-40% of the theorical; urea is recoverable and so the process by reinjection/reuse of urea recollected/recrystallized could be
set close to 90%.
My chemical point of view:
-Dinitrobiuret allows one to get the power of DNU with lower hydrolytical troubles.
-Density is highly enhanced what is good for brisance and VOD.
-Metalic salts of DNB are potential primaries, especially heavy metal salts.
-Most interesting amine salts would be di-hydroxylamonium, di-hydrazonium and di-ammonium.
Reaction of DNB with 1 equivalent of formaldehyde may form:
-A kind of diketo-RDX and methylene dinitramide related molecule (cyclo(-CH2-N(NO2)-CO-NH-CO-N(NO2)-)... this cyclic compound will be acidic owing to
its NH entrapped between two CO and might thus also form interesting primaries metal salts and interesting energetic amine salts (hydroxylamine,
hydrazine and ammonia).
-Also possible and more interesting a linear polymer (-CH2-N(NO2)-CO-NH-CO-N(NO2)-)n ... this will outperform any cyclic nitramine because any linear
polymer tends to reach higher densities than monomer owing to increase of Van-der-Waals attraction forces; also linear polymers tends to have lower
impact sensitivities. This polymer will also display acidic sites and might thus form also metallic primary salts and energetic amine salts.
-A second equivalent of formaldehyde may react on the acidic NH to form a methylol that is nitratable eather on the cyclic-monomer or on the linear
polymer (-CH2-N(NO2)-CO-N(CH2ONO2)-CO-N(NO2)-)n.
This can also result in bridging of two diketo-RDX like cyclic monomers (cyclo(-CO-N(NO2)-CH2-N(NO2)-CO-N)-CH2-(cyclo(N-CO-N(NO2)-CH2-N(NO2)-CO-) a
non-acidic/neutal molecule; or even better methylene bridging of various linear polymeric strands to make a non-acidic very high density
thermo-hardening or a rubber like energetic plastic.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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underground
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How can the hydroxylamonium salt can be form ? I can not see anywere any source of hydroxylamonium carbonate/bicarbonate e.t.c.
di-hydroxylamonium dinitrobiuret looks very promising as long as it is going to have only slightly negative OB
Also biuret because it consist of 2 urea molecules together, i guess it will be as much easy to nitrate it to dinitrobiuret salt as much easy the
nitrourea salt going to be.
[Edited on 27-2-2014 by underground]
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DubaiAmateurRocketry
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Potential EM from ANQ and NSC
Compounds like biuret, guanylurea, biguanide, and thereof gives less nitrogen content and more carbon. These types of compounds contain less hydrogen
bonds and function units per mass than urea and guanidine have. Therefore, I think guanidine and urea and their derivatives have much more potential.
Many of you might already seen this, Thomas M. Klapotke synthesized 1-Amino-3-nitroguanidine nitrate. With perfect OB balance, its hydrogen bonds
gives it safer impact sensitivity and higher density than HMX. Reaching a VoD of nearly 9600 m/s according to EXPLO5.04. DOI: 10.5560/ZNB.2012-0066
The paper's dinitramide salt is also promising, with a reported dehydration temperature of around 70 degree celsius, the impact sensitivity of the
hydrated salt is around 10J. This compound have a CO OB balance of nearly +20% and seems like a promising oxidizer. The dehyrated compound should have
over 1.9 density(the nitrate is already over 1.9, and dinitramide anion usually gives higher density) and the dehydrated salt probably a better impact
sensitivity than ADN since there're hydrogen bonds and the ammonium cation does not.
dinitrourea can react with hydrazine to give 4-nitro-semicarbazide according to this paper. However it only gives moderate yeild around 50%. I think 4-nitro-semicarbazide can be synthesized directly from HNO3 and semicarbazide
to give semicarbazide nitrate, and then treating it in sulfuric acid. However I did not find a paper saying that was possible. Another method could be
hydrazinolysis of nitrourea, did not find any paper on this reaction either. Anyways, I guess 4-nitro-semicarbazide could be protonated by acids like
HNO3, to form 4-nitro-semicarbazide nitrate, dinitramide, dinitrourea, dinitroguanidine etc.
[Edited on 28-2-2014 by DubaiAmateurRocketry]
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Boffis
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Has anyone ever actually tried to prepare biuret? I am in the process of trying out various method with wildly variable and erratic results. I could
do with a bit of practical advice. I have tried the simple heating of urea alone (yield very poor <3%), with inorganic salts under reduced pressure
(better results but not as good as the patent claims), with thionyl chloride (difficult to control reaction, excellant yield in a small scale trial
but full-scale 100g or urea yield seems very poor). I also tried the urea salt + K cyanate and again got modest results. Details to follow in a few
days.
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MineMan
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Look up tetrazolover
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Boffis
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@MineMan,
Look up tetrazolover
??
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MineMan
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Yup. He has a YouTube channel.
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underground
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After waching this video on youtube
https://www.google.com/url?sa=t&source=web&rct=j&...
i thought that i could try it the same on my own too
After about 2-3h of boiling urea, everything was solidified. Here is a photo of the stuff fully powderized
https://ibb.co/85xsL9y
I tried to react it with 65% NA. There was a rise in temp of 35oC and here is the result.
https://ibb.co/CvJXJSM
Here is urea nitrate in comparison
https://ibb.co/CQrm0Vh
Now i tried to nitrate some of this stuff with 200g SA 65g Kno3 and 25 of supposed biuret. During addition of supposed biuret there was a rise of
temp. The wierd this is that there was some bubbling .
https://ibb.co/hZLh32N
I guess there was a decomposition. Max temp during nitration was 35oC. Now i got no yields after crashing in water. Before crashing the mix was a bit
thick so i supposed that i got something. Anyway i dont know if i got no yields cause the temp was too high or because i just have not got any biuret
at all. I may try again to nitrate it at lower temps or try to detonate the stuff reaced with 65% NA.
[Edited on 19-5-2019 by underground]
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Laboratory of Liptakov
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Edited from patent: US3150177A
Claim:
1. A process for the preparation of biuret from urea, said biuret being substantially free of cyanuric acid, which comprises heating urea at
atmospheric pressure to about 140 Celsius. After form a melt, subjecting the heated melt to a reduced pressure of about 140 to 150 mm of mercury rod.
(edit / normal athmospheric pressure is 760 mm of mercury rod ) Raising the temperature ( at reduced pressure) of said melt over a period of about a
few minutes on150 to 160 Celsius. And simultaneously reducing the pressure to below about 75 mm of mercury rod. Result is stantially completely free
of cyanuric acid and sodium cyanurate.
2. A process for the preparation of biuret from urea as set forth in claim 4 wherein said aqueous solution of sodium hydroxide contains about 2 to 3%
dissolved NaOH.
3. A process for the preparation of biuret from urea as set forth in claim 4 wherein said aqueous sodium hydroxide solution containing said discharged
reaction mass is heated to about to level, to facilitate solution of said reaction mass.
4. A process for the preparation of biuret as set forth in claim 1 wherein said urea is heated in the presence of a catalyst which is soluble in and
does not form a precipitate with said aqueous alkali said catalyst being selected from the group consisting of disodium and boric acid.
........ ......It's time to determine the exact way to make pure Biuret from
urea. But without applying reduced pressure..........LL
Solubility urea is 108g in 100g water at 20 C
Solubility biuret is 2g in 100g water at 25 C
Melting point urea....134 C....Melting point Biuret.....190 C...= decompose
Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite and KC primer (2024)
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Boffis
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@Underground, nitration of biuret is recommended to be maintained at <0 C and also you have far to much KNO3. The reaction is nearly quantitative
with a 1:1 ratio for the mononitro compound. For the dinitro compound the excess of nitrating agent should still be a small excess say 5% to avoid
decomposition of the product.
Dr. Lipatkov. The problem I find with a lot of procedures is they are short on precise details. Separating biuret from urea or ammonium chloride is
easy, it is maximizing the yield per unit of effort that is the problem since urea itself is cheap. The best yield I have achieved was using a
procedure I found in a footnote to an old German paper. I translated it at the time and have it somewhere. Basically this procedure involved passing
chlorine into molten ammonia at c 140 C (yield c 55% assuming 2urea = 1 biuret). I have also tried the molten urea + sodium hydrogen phosphate (or
other salts) under reduced pressure to assist removal of the ammonia formed (11% with same assumption); the potassium cyanate + urea hydrochloride (8%
of theory, much cyanuric acid)/nitrate (30%) and thionyl chloride on urea (50%). They all work but each has its own little problems. If you have
access to thionyl chloride the last procedure is the simplest, if not the first is probably the next best but it has the problem of working with much
chlorine. I have had only limited success with the straight heating of urea, never >20%. The patent that describes the various salt catalysed
methods makes claims of 70% but I could not repeat these yields.
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Laboratory of Liptakov
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Thanks very much, Boffis. You do great research on this theme. I estimate, that I early leave the field of research on biuret theme. It seems, that
pure Biuret (95%?) is impossible produced.......LL
Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite and KC primer (2024)
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Boffis
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@Dr Liptakov, just incase you or someone else would like to try the Thiele & Uhlfelder "chlorine on urea" method I have attached my translation of
their paper, see the footnote at the bottom of p95 (original page numbers). There is some interesting chemistry in this paper.
Attachment: On Biuret and aminobiuret JLAC Thiele & Ulhfelder 1898 English.pdf (151kB)
This file has been downloaded 540 times
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