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[*] posted on 3-1-2021 at 20:39
Urea


Urea- there's a lot there. It's hard to keep track of the possibilities. Are the auto-condensation products of urea beyond biuret explored in energetics? Biuret is found. I can find very little on triuret, tetrauret and pentauret. Everything found seems unsubstantiated or unrelated to EM. Ie. from agriculture patents, (which is interesting in itself), but other than DNB, there seems very little.

Is there any exploration of the later condensation forms of urea in energetics?

; err I mean, whatchu think?

[Edited on 4-1-2021 by Hey Buddy]
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[*] posted on 3-1-2021 at 20:58


Should ammonia be liberated out of this bitch or what?

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[*] posted on 3-1-2021 at 21:00


An awful lot would depend on what you were trying to accomplish.
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[*] posted on 3-1-2021 at 21:08


Great, maybe somebody in beginnings will know about tetra and pentauret?
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[*] posted on 3-1-2021 at 23:35


You get isocyanuric acid and ammeline.
This is how isocyanuric acid is made commercially.
You can also get various other azines and tetrazole compounds as low level contaminants.

https://en.wikipedia.org/wiki/Cyanuric_acid
https://en.wikipedia.org/wiki/Ammeline
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[*] posted on 4-1-2021 at 00:31


Quote: Originally posted by j_sum1  
An awful lot would depend on what you were trying to accomplish.


Truly, apart from ammonia generation, hydrazine and urea nitrate, are there any collection of useful purposes for urea?
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[*] posted on 4-1-2021 at 02:37


Quote: Originally posted by Hey Buddy  
Great, maybe somebody in beginnings will know about tetra and pentauret?

For the record, threads of a general nature that open without a citation more properly belong in beginnings. It does not change the readership. But it does change the organisation of topics.
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[*] posted on 4-1-2021 at 03:35


@Hey Buddy; urea is a very useful compound in terms of being a starting material. Apart from buiret, isocyanuric acid an ammeline which are simply polymeric degradation products you can also derivatize it eg -> urea nitrate -> nitrourea -> semicarbazide -> whole world of semicarbazones and heterocyclics. Aliphatic amine + urea -> substituted ureas.

It can be used to prepare aromatic amines eg.; 4-nitrobromobenzene + urea = 4-nitroaniline; 2,4-dinitrochlorobenzene + urea; 2,4dinitroaniline and the related reaction picric acid + urea = picramide (2,4,6-trinitroaniline)

Alkalis + dry urea give cyanamides or cyanate depending on conditions.

From biuret via nitrobiuret to aminobiuret (actually a hydrazine derivative) to tetrauret

I have prepared buiret many times and I can tell you that none of the simple heating methods work very well. The two best methods unfortunately are very amateur unfriendly!! (one is via thionyl chloride and the other via direct chlorination of molten urea give yields >60%).

Aqueous lime water gives ammonia, Hoffmann's degradation give hydrazine etc. There is an entire monograph dedicated to the chemistry of urea.

If you want more specific help you will need to be a bit more specific on what you are trying to achieve. For instance are you simply trying to find some interesting /useful chemistry for it because you have a lot of it?
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[*] posted on 4-1-2021 at 04:24


Quick aside.

For the recrystallization/purification of urea, can water be used instead of ethanol/methanol?
The solubility curve of urea in water seems quite advantageous too ...



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[*] posted on 4-1-2021 at 05:52


Yes, boiling water can dissolve ~5 Kg/L while only ~.5 Kg/L will dissolve at 0 C.

edit: Urea is also great for electrolytic H2 production since it is extremely soluble in water and decomposes at ~.4 volts as opposed to water at ~1+ volts. As previously mentioned, it can be used to make cyanamides (heterocycle precursors, dehydrating agents, bases etc.) and isocyanates (also heterocycle precursors and versatile reagents for the preparation of amines, carbamates, amides, carboxylic acids etc.). It is in my opinion one of the most versatile and valuable reagents to the amateur since it can find so many uses at a very low cost.

[Edited on 1-4-2021 by njl]
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[*] posted on 4-1-2021 at 09:02


artemov,

You need to compare the impurity and the desired chemical curves.
In the case of urea, the primary impurity is usually biuret which is more soluble and has a flatter curve in alcohols.
If you are purifying fertilizer the urea is often mixed with ammonium sulfate which is much less soluble in alcohol so it can be crashed out of a water solution.

Ps. have you ever tried to pour or filter a saturated solution of urea in water?
Very viscous.

[Edited on 4-1-2021 by macckone]
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[*] posted on 4-1-2021 at 19:57


Thank njl and macckone.

Quote: Originally posted by macckone  

If you are purifying fertilizer the urea is often mixed with ammonium sulfate which is much less soluble in alcohol so it can be crashed out of a water solution.
[Edited on 4-1-2021 by macckone]


I dun really understand this part. Ammonium sulfate is much less soluble in alcohol, but it can be crashed out of a water solution?
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[*] posted on 8-1-2021 at 11:51


Quote: Originally posted by j_sum1  
Quote: Originally posted by Hey Buddy  
Great, maybe somebody in beginnings will know about tetra and pentauret?

For the record, threads of a general nature that open without a citation more properly belong in beginnings. It does not change the readership. But it does change the organisation of topics.


Thanks for mentioning this. I thought I was being taken out backdoor by the ear, maybe I peed on a rug or something.
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[*] posted on 8-1-2021 at 15:06


Quote: Originally posted by Boffis  
@Hey Buddy; urea is a very useful compound in terms of being a starting material. Apart from buiret, isocyanuric acid an ammeline which are simply polymeric degradation products you can also derivatize it eg -> urea nitrate -> nitrourea -> semicarbazide -> whole world of semicarbazones and heterocyclics. Aliphatic amine + urea -> substituted ureas.

It can be used to prepare aromatic amines eg.; 4-nitrobromobenzene + urea = 4-nitroaniline; 2,4-dinitrochlorobenzene + urea; 2,4dinitroaniline and the related reaction picric acid + urea = picramide (2,4,6-trinitroaniline)

Alkalis + dry urea give cyanamides or cyanate depending on conditions.

From biuret via nitrobiuret to aminobiuret (actually a hydrazine derivative) to tetrauret

I have prepared buiret many times and I can tell you that none of the simple heating methods work very well. The two best methods unfortunately are very amateur unfriendly!! (one is via thionyl chloride and the other via direct chlorination of molten urea give yields >60%).

Aqueous lime water gives ammonia, Hoffmann's degradation give hydrazine etc. There is an entire monograph dedicated to the chemistry of urea.

If you want more specific help you will need to be a bit more specific on what you are trying to achieve. For instance are you simply trying to find some interesting /useful chemistry for it because you have a lot of it?


This is what I've come to understand. And correct me with anything I'm not understanding; That urea is both a simple molecule and a functional group(?). Massive exponential spread of possible extensions in step series. > GN, DPT, Hydrazine, semicarbazide, carbohydrazone, NH3, etc.

In terms of energetics, upon heating under specific conditions,, a series of condensation transformations occur. The transition is not a linear progression by temp, but by a heating and pressure/oxygen matter. Have the macromolecules been explored? I can't find anything.

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It's all quiet now. Maybe I've asked something stupid?
Is there any reason not to nitrate or perchlorate the higher condensation products or macomolecules in general? I'm totally unfamiliar with this, and chemistry in general, so I don't know if this is a silly question. Any help?

[Edited on 9-1-2021 by Hey Buddy]
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[*] posted on 14-1-2021 at 06:43


Update: I've found energetic research on melamine, ammeline, and cyuranic. Of course biuret is already widely explored..
Have still not located any research on triuret tetrauret or pentauret, which are all condensation products. If anyone is aware of research on energetic compounds of those please respond.
Have located patents on isolation processes for triuret but nothing on tetrauret nor penta. If anyone knows a process to isolate those please respond.
Id like to experiment with urea beginning with the lesser explored areas first, thank you.


[Edited on 14-1-2021 by Hey Buddy]
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[*] posted on 14-1-2021 at 12:27


In Boffis' post above they describe the route to isolate tetrauret.
There is more information in here, also provided by Boffis under another thread.
Very interesting stuff!
http://www.sciencemadness.org/talk/files.php?pid=613206&...
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[*] posted on 15-1-2021 at 17:40


Excellent, thank you. --Two documents I've found of interest are a 1950s procedure of melamine and other products by simple heating in pipes at various densities and Temps. The second is experimental tetrauret macrocycles. Really a dizzying array of possibilities with urea. It's plastic derivatives are fascinating too. Apparently urea products can be used for desensitization coating of classics like RDX.

Attachment: Melamine from Urea.pdf (1.8MB)
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Attachment: Tetraurea.pdf (2.7MB)
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[Edited on 16-1-2021 by Hey Buddy]
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[*] posted on 16-1-2021 at 22:57


The urea likes to recrystalyze

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[*] posted on 26-1-2021 at 06:22


Update: Have worked up through biuret to melamine.
Experimenting now with gCN/BgCN. Biuret is very easy in isolation, as it's the first condensation, limited to temp ceiling 189C. Biuret conversion appears reasonsbly possible in open vessels. Triuret, tetrauret, pentauret, cyuranic, ammelene, ammelide, are much more difficult in discrimination. The isolation of these by thermal condensation without gas feed is not well understood. building some vessels for pyrolytic condensation and gas feed now.

Currently in digressions of gCN. Sort of necessary pit stops on the way to EMs. Its watersplitting ability in solar applications and the gCN catalytic abilities, which seem pretty incredible. Within this there is microwave production of melem using KNO3 as an exfoliator. Urea and KNO3 mixes produce high surface area gCN for cats. But I'm interested in its effect on homogenous formation of melamine enroute to melem.

The most significant condensation of urea where EM is concerned, (imo) is melem/melon. The production of gCN passes through the stages of melamine and then melem prior to being calcinated into gCN.

Melem is a heptazine from urea. Melon appears to be an autocondensed poly lattice of melem. Energetic heptazines and be made from melem. It is pretty unexplored for the most part. A lot of theoretical compounds. I've read the claim that n-oxide impinged heptazines are theorized to have impact and thermal sensitivity from the range of TNT all the way up to RDX with several of the compounds having greater vod than cl20. Most of the theoretical compounds have greater vod than HMX and with less sensitivity. This is the reason i am interested in Urea. Its products are a vast library and in this area it can be purchased bulk by anyone at $316/Ton.

Will continue to explore and post useful findings. see attachments on heptazines.

I dont schpreken ze Deutsch is anyone would like to help explain that 2nd one i would love to know more. Thank you.



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[Edited on 26-1-2021 by Hey Buddy]

[Edited on 26-1-2021 by Hey Buddy]

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[*] posted on 26-1-2021 at 07:51


Forgive my ignorance but is gCN/BgCN cyanoguanidine and cyanobiguanidine (correct nomenclature aside)? When you say "kno3 and urea produce high surface area for cats", do you mean for catalysis?
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[*] posted on 26-1-2021 at 08:15


Making Graphitic carbon nitride (g-C3N4) from urea
https://www.sciencemadness.org/whisper/viewthread.php?tid=154866#pid631050




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[*] posted on 26-1-2021 at 08:40


Quote: Originally posted by njl  
Forgive my ignorance but is gCN/BgCN cyanoguanidine and cyanobiguanidine (correct nomenclature aside)? When you say "kno3 and urea produce high surface area for cats", do you mean for catalysis?


My apologies, "gCxNx" is the way graphitic carbon nitride is described in energy study literature. BgCN is boron graphene carbon nitride. "Cat" im just contracting "catalyst".

Here is some info on KNO3/Urea catalysts look under "CNU-30":


Attachment: Microwave melamine carbon nitride.pdf (6.9MB)
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[*] posted on 26-1-2021 at 09:05


See what I'm talkin about?

Urea.

It's where it's at.

Urea covers everything from low order det to fastest and everything between.

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[*] posted on 26-1-2021 at 09:17


Quote: Originally posted by Hey Buddy  
Biuret conversion appears reasonsbly possible in open vessels.

Very much is, i did it in a 500ml beaker with a RBF on top. worked perfectly fine. The isolation of the biuret is easier with beaker also, just add dilute hydroxide (2-3% or so, as long as it stays above 9-10) , heat till dissolved, cool and collect crystals, then rex it from distilled water to rid the last trace of hydroxide.
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[*] posted on 26-1-2021 at 15:32


artemov,
Crashing out of water using alcohol as a cosolvent is useful for a number of purifications.
The basic procedure is to dissolve a urea/ammonium sulfate mixture in minimal water.
Then add about 4 times as much dry alcohol as solution.
The ammonium sulfate will form fine crystals free from urea.

Ammonium sulfate is only slightly soluble in 80% alcohol while urea is very soluble.

The procedure I actually use involves dissolving it in significantly more water than necessary and evaporating most of it off, then adding alcohol.

Since the stuff I get is fertilizer grade, I can filter off insoluble impurities with the excess water.
Then get nice pure crystals that I can rinse with alcohol to get rid of any remaining urea.

The alcohol can be redistilled and reused.
The remaining urea can be recrystalized from dry alcohol.

The mix I get is about 90% ammonium sulfate and 10% urea.
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