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Author: Subject: Formation Conditions for NI3 vs NCl3
hodges
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[*] posted on 5-2-2005 at 17:04
Formation Conditions for NI3 vs NCl3


Nitrogen trichloride can be prepared by bubbling chlorine through an acidic solution of an ammonium salt. Not that anyone should do this, of course. OTOH, nitrogen triiodide is prepared by adding NH4OH solution to solid iodine crystals.

Presumably, the method of generating nitrogen trichloride will not work for nitrogen triiodide. I base this presumption on the fact that the MSDS for iodine warns against contact with NH4OH, but not ammonium salts in general. Also presumably, you couldn't prepare nitrogen trichloride by bubbling chlorine gas into NH4OH, as NH4OH is not acidic.

So why do these differences in conditions for formation exist between the two analogous compounds?
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Marvin
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[*] posted on 5-2-2005 at 22:29


NI3 is very hard to make and won't occur under those conditions in any real amount.

N-Cl bonds hydrolyse to ammonia and hypochlorous acid, so to tip the balence in favour of NCl3 the solution must be acid.

NI3.NH3 is an insoluable adduct, something like a polymer. For this to form large amounts of free ammonia must be in solution to abscond with any NI3 that is produced - you only get a yeild because of the very low solubility of the product and this is what tips the balence, so the solution must be alkaline.
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[*] posted on 6-2-2005 at 10:05


Actually, you CAN make NCl3 from chlorine and NH4OH, when chlorine reacts with ammonia to form chloramine HCl is made, this makes the solution acidic, aiding further reaction.



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[*] posted on 6-2-2005 at 12:36


Thanks, Marvin. The solubility thing makes sense.
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kazaa81
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shocked.gif posted on 19-2-2005 at 14:32
NCl3 different synthesis?


Hi,

in roguesci's forum I found a different synthesis of NCl3, with acetic acid, sodium hypochlorite and ammonium nitrate (probably any ammonium salt would be right). I've reformatted this and post it now:
==
Nitrogen chloride

3 NaOCl + 2 CH3COOH + NH4NO3 -----> NCl3 + NaNO3 + 2 CH3COONa + 3 H2O

300ml of 5-7% NaOCl solution ,
50ml of 70% CH3COOH
solution of 10g NH4NO3 in 30ml of water

1)cool the solutions in refredgerator (about -10C)
2) pour 300ml NaOCl into a 0.5l plastic bottle(cola)
3) add 25ml of CH3COOH to NaOCl by small parts
4) add the ammonium nitrate solution to the bottle by small parts
(extremely bad smell ! the solution must become yellow)
5) add 25ml CH3COOH to the bottle by small parts
6) leave the bottle (don't close it !) for 1-2 hours
The solution must become colourless and a yellow-orange liquid must gather on the bottom (about 10g)
Then close the bottle and throw it somewhere

The reaction between Cl2 and NH3(classical method) goes
the following way:

1) Cl2 + H2O = HCl + HOCl
2) NH3 + HOCl = NH2Cl + H2O
3) NH2Cl + HOCl = NHCl2 + H2O
4) NHCl2 + HOCl = NCl3 + H2O

So, it's not necessary to obtain Cl2, and then bubble it into
NH4NO3. Besides, working with gaseous Cl2 has many problems.
==
Probably less concentrate acetic acid can be used and another NH4+ salt, for example NH4HCO3 (baking ammonia); the previous text is a crap, but if the synth. works, why not take a read?
I need confirm about the work of the previous synth.!

Thanks for help and hope that I've helped
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kazaa81
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[*] posted on 20-2-2005 at 09:49
can anyone post a reply?


Hi,

can anyone post a reply to the previous post?

Thanks very much
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[*] posted on 20-2-2005 at 10:24


The method seems very similar to one of the methods to make organic hypochlorites, the only difference being the reactant being a ammonium salt rather then an alcohol. I don't think this would work with any acetic acid of considerably greater dillution, I'm assuming it affects the system in more ways then just altering the pH, one effect probably being the removal of yet more water from the system.

Please kazaa, you've been around here long enough to know the procedure for bringing up a dead topic, research, find something new, post that, and hope for the best.




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garage chemist
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[*] posted on 21-2-2005 at 09:54


The previously posted AN/acetic acid/NaOCl route of NCl3 production sounds very good, because Axt successfully produced tetrachloroethylenediamine by substituting AN with ethylenediamine.

But... it is pure suicide to make 10 grams of NCl3!
My Chemistry book says that NCl3 explodes on contact with chlorinatable organic substances.
I think PET is definately chlorinatable, with all the benzene rings of the terephthalic acid.

Better use glass containers and work with small amounts.
Also, NCl3 vapors are very irritant and toxic.
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[*] posted on 21-2-2005 at 11:00


Quote:

Actually, you CAN make NCl3 from chlorine and NH4OH, when chlorine reacts with ammonia to form chloramine HCl is made, this makes the solution acidic, aiding further reaction.


Wont the HCl react with the ammonia that is still present???Or do you have to let it react to chloramine and HCl(and NH4Cl then too)before the reaction will complete?

cheerz




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[*] posted on 1-3-2005 at 15:17


I remember back when I was in high school I tried to make nitrogen triiodide by mixing household ammonia with iodine tincture. No success. Recently I tried this again under more controlled conditions. I mixed about 1/2 oz of iodine solution (which contains something like 2% free iodine and 4% KI) with clear household ammonia. The solution immediately turned black. However, there was almost no precipitate. When I tried to filter the percipitate I ended up with nothing. However, I did notice a thin black layer clinging to the bottom of the plastic cup where I did the reaction. Upon drying, surprise! I was able to get this thin bottom layer to detonate by scratching it wit a popsicle stick. Obviously a horrible yield, but yes it is possible to make nitrogen triiodide by simply mixing tincture of iodine with household ammonia.

I then tried extracting the iodine from the other half of the 1oz bottle of tincture of iodine. I added 3% H2O2 and a bit of HCl (muriatic acid). Over a period of several minutes, most of the iodine precipitated leaving the solution almost transparent yellow. I carefully poured off as much liquid as I could, then washed several times by adding water, stirring, and waiting for the iodine to settle again. Finally I used a pipette to get rid of all the water I could and left the iodine to dry. This was yielded a pretty good amount of iodine (I did not weigh it since 1. it probably sitll has some water left and 2. quite a bit of the iodine evaporated with the water).

Iodine is a bit nasty when it comes to staining things. The wall next to where the iodine was drying turned yellow (the color went away after a day or so once I got rid of the iodine). I also have a small amount of I2 stored in a plastic 35mm film canister. Apparently some iodine gets through the plastic. The masking tape I used to label the container gradually turned orange, and the canister leaves an iodine stain on anything it sits on, even though I have repeately washed the outside of the container and know there is no I2 on the outside.
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[*] posted on 1-3-2005 at 16:10


I, too have tried the tincture + ammonia method without success. An alcoholic solution of iodine added to the same ammonia instantly precipitated a black solid. After leaving it in the solution a little while and drying it, I found that it was indeed NI<sub>3</sub>. A little OT, a green material was left in the test tube. What would this be? The alcohol was decently pure EtOH (E-Z or Klean Strip, IIRC), the ammonia was Homebest clear ammonia, and the iodine was reagent grade.

For future reference, bleach cleans iodine stains very well.
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smile.gif posted on 3-4-2005 at 17:33
HMMM!


Bleach cleans iodine stains? Cool! Must convert it to iodate. I have some latex gloves heavily iodinated. We will see if this works on rubber too! I have been cleaning up with a 50/50 denatured alcohol strong ammonia mix. Added considerable iodine and it would clear up on its own. THis time however, I added the mother load and it may be exhausted. it is a deep red color and it does not seem to want to clear up.



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[*] posted on 4-4-2005 at 12:40


Unless some one knows better about NI3, I only messed about with it on a small scale. As soon as you try to scale it up you should learn or else you have a problem.
mick
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[*] posted on 7-4-2005 at 14:34


I have made NI3 and I can tell you no matter how smart you are it is stupid to let more than one gram of this stuff dry at one time. These crystals have a tendancy to go off by themselves for no reason at all.
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