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Author: Subject: anhydrous ammonia from urea?
Sauron
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[*] posted on 14-9-2007 at 21:25


COS = carbonyl sulfide, how to deal with that?

S.C.Wack used to provide a compendium of selected monographs from Inorg.Syn, I think on rapidshare, and perhaps on ftp #1 (Axehandle) but thus far I he has resisted all blandishments to re-up this item, to FTP #2, or 4shared or something.

I dunno if this item is even among his handpicks.
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Eclectic
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[*] posted on 14-9-2007 at 21:32


You feed the COS with oxygen to your heated vanadium catalyst tube. :D
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Mr. Wizard
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[*] posted on 14-9-2007 at 21:42


You can liquefy ammonia with simple steel and iron fittings. There used to be a lot of links when you search for Crosley IcyBall. There was even one made with regular steel plumbing pipe and it worked. (Larry Hall Icyball) also see IcyBall Patent #1,740,737 and IcyBall Patent #1,811,523
I downloaded a copy of the sites main information. Try searching for it. Liquid ammonia is dangerous and attacks brass and copper. Liquid propane tankers are sometimes used to haul liquid ammonia in the summer season, if they have the right fittings, that is stainless steel or steel valves.

Strong ammonia fumes will attack every moist, damp, or wet area on your body. It can render your eyes to trash in seconds and leave your crotch and armpits a scalding wound. Emergency workers are known to spread generous amounts of petroleum jelly (Vaseline) on sensitive areas, before using a self contained breathing apparatus to go in and stop a leak at a plant using ammonia. On the other hand a spray of water can absorb enormous amounts of the gas. An ammonia leak is a real nasty item, for you and all your neighbors, and it goes on for hours and hours and hours. Liquid ammonia refrigerates itself so well that it will take forever to evaporate. I've been told a glass of liquid ammonia, without any insulation will last over 24 hours.

I don't know how this will work using Urea, but to say it can't be done isn't true.
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Sauron
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[*] posted on 14-9-2007 at 21:55


The German patent (looks like Akso's chemists) for the two step process:

Enka Glanzstoff, DE 1 297 088, 1967 (H. Maegerlein, H. Rupp, G. Meyer).

One step process at 115 C and 5 bar, this one definitely Akso

Akzo, DE 3 508 404, 1986 (G. Meyer, G. Sudheimer, H. Zengel, H.

BTW ammonium thiocyanate and thiourea are isomeri just as urea and ammonium cyanate are. Heating ammonium thiocyanate gets you thiourea. But slowly and incompletely. I wonder if this goes both ways? The answer is yes, it is an equilibrium but the two (thiourea and thiocyanate) are very hard to seperate so this method is not employed preparatively and is only of historical interest.

EUREKA!

Org.Syn. to the rescue

Ammonium dithiocarbamate. Gaseous ammonia is passed into 250 ml. of 95% ethanol (Note 1) contained in a 1-l. Erlenmeyer flask immersed in an ice bath until the gain in weight is 39 g. (2.3 moles). To this solution, still cooled by the ice bath, is added a well-cooled mixture of 76 g. (60 ml., 1 mole) of carbon disulfide and 200 ml. of ether. The flask is stoppered loosely (Note 2) and allowed to remain in the ice bath for 2–3 hours and then at room temperature overnight (Note 3). The mixture is again cooled in an ice bath or refrigerator, and the crystals are collected by filtration (hood), sucked dry, and washed on the filter with two 50-ml. portions of ether. Air is drawn through the crystals for 5 minutes (Note 4) to effect removal of most of the ether. The product is used promptly without further treatment; the weight of the lemon-yellow solid varies between 80 and 90 g., depending principally on the completeness of the removal of the solvent.

Collective Volume 3, p.763

I will attach the entire prep, which is of Rhodanine, so you will have the references and the notes for Part A which is the ammonium dithiocarbamate. No interface reactor, no activated charcoal, just ethanolic NH3 and CS2/Et2O and you have what you want to pyrolize at 95-100 C to NH4SCN.

So there IS a simple easy way to make ammonium thiocyanate after all.



[Edited on 15-9-2007 by Sauron]

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Sauron
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[*] posted on 15-9-2007 at 01:13


PS

The attached is the JACS article on which the Org.Syn. prep of rhodanine was based, for comparison of their procedure for ammonium dithiocarbamate. I suspect the Org.Syn. variation is a little more thoroughly described.

Sorry about the double post!

[Edited on 15-9-2007 by Sauron]

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S.C. Wack
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[*] posted on 15-9-2007 at 04:32


Some corrections if I may digress from the point of this thread entirely.

I specified "easy convenient amateur-friendly method", which CS2 is not exactly, as much fun as it is to make or spend outrageously large sums of cash on.

Axehandle has FTP#2. There is a thread with this title.
No one has asked me for the Inorg Syn collection. [edit- I obviously do not recall such a request] The relevant preparation isn't in that djvu anyways.
I uploaded everything I had of my own at the time to the newer FTP, and it was all erased.
I put all of my book scans on 4shared along with other useful pdfs for a total of 975 MB for many months, in fact I started the thread on 4shared if you look, and the WWW button which is no longer at the bottom of my posts, but was for some time, took you directly to them. One can find amongst my scans the preparation of ammonium thiocyanate from CS2 and ammonia.

The 4shared collection is no longer there because my last 3 uploads and the rest of the collection got a single download between them in the last 3 months, and that one only because Mephisto wanted to see it, from its mention in the book scanning thread.

On topic- "from urea?"
No. Stick with what has been tried and true for many years for ammonia generation or just about anything else and you'll get more done. OK that may be construed as discouraging experimentation... Experiments have shown that it is often a more efficient use of time and money to let other people do the major experimentation for you. One often has their hands full with just the little tweaks.

Quote:
Originally posted by 12AX7
...And SO2, and H2S. Now there's a refrigerant that'll discourage tampering!


I ran into a working SO2 fridge a couple years ago from what, the 40's? Still around. Wonder if they're worth anything.

[Edited on 15-9-2007 by S.C. Wack]
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Sauron
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[*] posted on 15-9-2007 at 04:51


Actually I asked you for the Inorg.Syn. files back in Dec or Jan and you gave me an unresponse. Axhandle isn't around any longer to answer requests for admission to his FTP site. To the best of my knowledge your stuff is not on MadHatter, I have been all over that one and have not seen it. I still would like to have it, but, whatever.

I think we have got ammonium dithiocarbamate pretty well covered, details of the conversion of that to the thiocyanate and purification of same would be nice (for Eclectic). As for myself I will just buy the thiocyanate if I decide to try this. Fortunately this is still a free country and I can pretty much buy what I like. That includes cylinders of NH3 should I so desire.
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Eclectic
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[*] posted on 15-9-2007 at 06:25


Ammonia based refrigeration is good in situations where you need cooling powered by a low grade heat source, or electricity is not available. Such a RV camping, or remote locations off the power grid, or situations where you might need refrigeration even if the power goes off for a week.

S.C., I think the old G.E. SO2 refrigerators may be collector's items if they are in good shape and still working. Please post a link to the Inorganic Synth. prep of Ammonium Thiocyanate in volume 3 if you have it? I don't understant kmno4's link: http://55158856/wasny ???

[Edited on 9-15-2007 by Eclectic]

OH! I see, it's an IQ test. I guess I passed. :D




[Edited on 9-15-2007 by Eclectic]
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[*] posted on 15-9-2007 at 07:19


Would the catalytic decomposition of urea via Urease be worth a try? A large amount of Ammonia/CO2 gas could be formed with little use of other chemicals (just a little bit of phosphates for pH buffer). Sperating the two gases and maintaing optimal conditions for the enzyme are the only things I can think of.

Or perhaps for the engineering type one could desgin a vessel in which urea + water react at high pressures/temperature?

Ammonia on demand
http://www.freepatentsonline.com/7008603.html
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Eclectic
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[*] posted on 15-9-2007 at 08:12


V2O5 (with or without tungstates) will catalyze urea hydrolysis at 100 C or so. You'd need a good condenser design to avoid blockage by solid ammonium carbonate, then you still have to get rid of the CO2 and water, unless you want to just use ammonium carbonate as your ammonia source in your reactions.


@Sauron
Check your 4share root folder.

[Edited on 9-15-2007 by Eclectic]
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[*] posted on 11-8-2008 at 15:20


Quote:
Originally posted by Eclectic
V2O5 (with or without tungstates) will catalyze urea hydrolysis at 100 C or so. You'd need a good condenser design to avoid blockage by solid ammonium carbonate, then you still have to get rid of the CO2 and water, unless you want to just use ammonium carbonate as your ammonia source in your reactions.


@Sauron
Check your 4share root folder.

[Edited on 9-15-2007 by Eclectic]



Sorry for a thread revival but...I was wondering if this could some how work out as a crude way to get mostly CO2 free ammonia...

The ammonium carbonate and water is mixed with 2 mols of an organic amine (high boiling point). The mixture is lightly heated and hopefully mostly pure ammonia is collected in a container full of water.

The organic amine could then be regenerated by heat and or vacuum?

(NH4)2CO3 (aq) + NHxRx (aq) + heat ------> NH3 (g) + (NHxRx)2CO3
NH3 (g) + H2O ----> NH4OH(aq)
(NHxRx)2CO3 + heat/vacuum? --------> 2NHxRxOH + CO2(g)

or perhaps just using a diver's solution(ammonia/ammonium thiocyanate would be a better idea to seperate the two gases?

[Edited on 11-8-2008 by DeAdFX]
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