How to remove chloride ions?

[Turel]

What would a recommended method be to isolate an inorganic azide from a solution of azide ions and chloride ions?

[gsus]

is the other azide inorganic? the chloride? are there other functional groups? fractional distillation may help. et20 can't hurt. alcohols might be useful if nothing on the molecules reacts with them. any THF or DMF or DMSO on hand? will the presence of other things actually hurt in the next step?

[Turel]

The solution is aqueous alkalai or calcium azide and chloride. Completely inorganic, no functional groups. I just want to isolate the azide from the chloride. Every precipitation I have looked up yields both precipitates for the azide and chloride, which yields no seperation.

I don't care what is removed, either the azide or chloride, as long as I can isolate an inorganic azide. I can get all of those solvents.

Do you know of any solvent/cation combination which yields solvation of one anion species but precipitation of the other? Any combination that does this is acceptable. It's pretty open, as the cation species is variable (whatever makes the seperation work will be used) so if an nswer only works with potassium, or calcium, or whatever, that is fine. The goal is just seperation of azide from chloride, all other variables and ions are able to be altered to suit the process.

-T

[gsus]

add lead nitrate, which will precipitate the well known lead azide. i say well known because it is used as a detonator. absolutely do not grind or let dry! wet is stable but explosions have occurred from it being poured down the drain, only to dry out just enough on the sides of the pipes to blow up on passing truck. the nonexplosive alkali and alkearth azides are all sol in H2O, so getting them to precip could b a bitch. you could evap most of your solution and slowly add ice cold alcohol instead. most but not all of the N3 will probably come out if you add enough.

fall down go boom

[Vitus_Verdegast]

IIRC calcium azide should be relatively insoluble in aqueous alcoholic solutions, so why not try adding half of the volume of alcohol?

Maybe it would be a good idea to add some, filter off precipitate, add some more, filter etc...? I know this works for sodium azide, but I can't find anything on calcium azide for the moment.

[politoxicomania]

Try to precipetate AgCl.

Or Acetonitril as solvent for the azid.

[Turel]

to gsus:

That won't work because PbCl2 is also just as insoluble in water, and both will precipitate equally, yielding no seperation. I am fully aware of the properties of lead azide, in fact that is the intermediate needing to be processed. PbN6 is nowhere near as dangerous as you make it to be. It is used as a military detonator for smaller explosives due to its strong insensitivity to drop-shock and moderate unlocalized heat. It takes a moderate shockwave from a primer, or intense heat from an ignitor wire to detonate PbN6. In my opinion, PbN6 is safer than NaN3, because of its insolubility, the risk of accidental HN3 release is minimized. HN3 is the real baddie to worry about.

Rest assured, I know what I am doing, and won't hurt myself.

Vitus: I hope you do recall correctly, because I searched for pure alcohol solubilities and both common and heavy metal chlorides and azides have equal insolubilities. Fucking annoying as hell. You say aqueous alcoholic precipitation works for certain on NaN3? I will try this then.

politoxocomania: AgN3 is insoluble as well. No seperation. I will try using acetonitrile if the alcohol does not work.

Thanks for your replies. They are much appreciated.

[politoxicomania]

But there must be a difference in solubility of the AgCl and AgN3. If carefully titrated it must be workable to crystallize them fractionated.
Dont know the exact L of AgN3 but i bet it not smaller than
L AgCl = 1,6 E-10   isnt it ?

[dioulasso]

AgN3 is also explosive!

[gsus]

i said Pb nitrate not Cl! the nitrate cause it is easily made from Pb. as for the Ag azide, the problem is insolubity of the Ag salts and even if there was one you'd still get a badass azide. az for danger, look up industrial accidents / PbN32.
i definitely remember being warned to never pour azide soln. down the drain, lest Pb pipe convert it to the Pb az.
 as for sol in alcohol, my copy of the CRC gives the (low) solubility but of course you wont evap your soln absolutely, so there may b interference in getting as much out as possible. consider azeotropic dist. of alcoholic CaCl2/H2O/CaN32 to get rid of the water if precip seems incomplete.

your humble servant and his humble chemistry

[Turel]

I know you said lead nitrate. I meant it will yield no seperation, because lead nitrate will exchange nitrate ion for both chloride ion and azide ion. You add lead nitrate, and both lead azide and lead chloride will precipitate, yielding no seperation of chloride from azide.

[gsus]

ive smacked myself in the head too many times. did not look up solubility of  the Cl. but you explain it well enough for me to grasp now. will think about my posts from now on. no, really.
  i doubt the Pb was tried tho. sorry if it was! i have nothing constructive to add here except an example of what happens when you dont cover your bases. and that is as important as it gets in this field.

fuckup=death