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Topic: purification of PCl3  (Read 14558 times)

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Offline Babcock_Hall

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purification of PCl3
« on: June 22, 2012, 05:10:05 PM »
I plan to distill some PCl3 for two types of chemical reactions (I have seen distillation used in a paper by Tolkmith from 1958).  I don't have a copy of Perrin et al. handy.  I seem to recall reading a paper in which a worker refluxed it before distilling, but I cannot find a reference.  Does anyone think that refluxing would significantly help or hurt the purity?  I might hazard a guess that this would drive off HCl.

Offline cheese (MSW)

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Re: purification of PCl3
« Reply #1 on: June 22, 2012, 08:00:05 PM »
Phosphorus trichloride [7719-12-2] M 137.3, b 76°, d 1.575, n 1.515. Heat it under reflux to
expel dissolved HCl, then distil it. It has been further purified by vacuum fractionation several times through a
-45° trap into a receiver at -78°. [Forbes Inorg Synth II 145 1946.] HARMFUL VAPOURS.
Perrin 6th ed p 482
Doesn't mention doing distillation under N2/vacuum but I would.  If distilling at RT
attach outlet to drying tube with KOH pellets?

Offline Babcock_Hall

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Re: purification of PCl3
« Reply #2 on: June 26, 2012, 12:08:21 PM »
Thank you.  When I opened the bottle, there was some release of pressure and a little bit of mist.  This might have been HCl gas, but I am not certain.  The bottle had not been opened in several years.  I would suggest opening a bottle of this reagent with care.  I wore gloves and goggles and worked behind a clear plastic shield.

Offline cheese (MSW)

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Re: purification of PCl3
« Reply #3 on: June 26, 2012, 11:23:38 PM »
Good grief!!  What if the bottle had 10 atm of HCl from prolonged hydrolysis?
My guess is PCl3 causes severe burns.  I know what I would have done and
it doesn't involve opening a bottle of a dangerous chemical that is several years old.
As Monty Python would say, Run Away, Run Away!!
You can obtain 250 g of PCl3 (98%) from STREM for $41US.
If you want to know how your supervisor should have disposed of the old
bottle of PCl3 let me know.
Incidentally, I meant distilling at 1.0 atm not RT.

Offline Babcock_Hall

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Re: purification of PCl3
« Reply #4 on: June 27, 2012, 10:27:46 AM »
Well, OK, what would you have done with the old bottle?

Offline discodermolide

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Re: purification of PCl3
« Reply #5 on: June 27, 2012, 11:00:52 AM »
Well, OK, what would you have done with the old bottle?

I would have put it in a large tin sealed it and send it to be incinerated.
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Offline ajkoer

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Re: purification of PCl3
« Reply #6 on: September 24, 2012, 12:25:24 PM »
Or, make holes in the top of the PCl3 container and throw it into a large vat of water containing some NaOH or NaHCO3.

 The reaction should form HCl or NaCl, H3PO4 or Na3PO4 depending on the amount of NaOH.

Offline discodermolide

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Re: purification of PCl3
« Reply #7 on: September 24, 2012, 12:33:18 PM »
That is an explosion waiting to happen. I would recommend anyone do this.
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Offline curiouscat

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Re: purification of PCl3
« Reply #8 on: October 11, 2012, 07:32:41 AM »
That is an explosion waiting to happen. I would recommend anyone do this.

Would or would not?

Offline discodermolide

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Re: purification of PCl3
« Reply #9 on: October 11, 2012, 07:59:56 AM »
would not
Cannot type.
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Offline 408

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Re: purification of PCl3
« Reply #10 on: October 11, 2012, 08:57:09 AM »
Well, OK, what would you have done with the old bottle?

I would have done what you did, open it and distill.  We have PCl3 that age in our lab too.

I doubt the ability of enough water to get in to produce 10 atm of HCl, while simultaneously not allowing HCl out. 

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