Dr. Beaker
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Purification of TiCl4
Hi all,
I need very pure TiCl4. I have a bottle of the comercial (97% I believe) that probably contaminated by partial hydrolysis products like oxocloride and
HCl/TiCl6(-2).
I have 3 option I can think of:
1. distilation(vacum or atmospheric) - but I worry that it'll be dificult to eliminate the HCl, which is the stuff that cause the greatest problems to
me.
2. to stirr the comercial stuff with a base that won't react with TiCl4 and its conjugated acid also won't...(is that possible?) CaH2 comes to mind,
though I'm not sure it won't react with TiCl4.
3. I know there's a way to react TiCl4 with ethers to get an etherate. TiCl4*2THF is a crystaline solid and can be recrystalized from CHCl3. the only
problem is that the THF is there to stay and can in itself make problem to my reactions later on.
I'll apreciate any thoughts/suggestions you might have.
Thanx!
[Edited on 16-12-2006 by Dr. Beaker]
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ziqquratu
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From Perrin "Purification of Laboratory Chemicals", 3rd ed.
Titanium tetrachloride [7550-31-0] M 189.7, b 136.4, d 1.730. Refluxed with mercury or a small amount of pure copper turnings to remove the last
traces of light colour [due to FeC13 and V(IV)Cl4], then distilled under N2 in an all-glass system, taking precautions to exclude moisture. Clabaugh,
Leslie and Gilchrist [J Res Nar Bur Stand 55 261 1955] removed organic material by adding aluminium chloride hexahydrate as a slurry with an equal
amount of water (the slurry being ca one-fiftieth the weight of TiCl4), refluxing for 2-6h while bubbling in chlorine, which was subsequently removed
by passing a stream of clean dry air. The TiCl4 was then distilled, refluxed with copper and again distilled, taking precautions to exclude moisture.
Volatile impurities were then removed using a technique of freezing, pumping and melting.
Out of curiousity, is there any major reason you need to purify that? I've never personally used the 97%, but others in my lab certainly have, and
they've never had any problems with it straight out of the bottle (you know, aside from the ridiculous reactivity of the reagent itself, particularly
when transferred outside of a glovebox!).
[Edited on 16-12-2006 by ziqquratu]
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Dr. Beaker
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Thanks for the info Ziqquratu.
It seems my only option to remove HCl is to freeze with liquid N2 and de-gas...
If I got you right you're saving your TiCl4 in your glovebox. We're keeping it outside and transfer it with a syringe directly to the reaction vessel.
I and others worked like that for years and had no problems. (we're making organometallic complexes for olefin polymerization). probably the
impurities were eliminated in the product purification stages.
however recently the reactions fail (I can see in 1H NMR the protonated ligand in large quantities => something acidic gave it the proton. I
started by working with ultra dry solvents (2nd dist. from NaK directly on the vacuum line) and then I disassembled the line, cleaned it and
reassembled again + dried with a flame under vacuum. it didn't change anything, so my next suspect is TiCl4.
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chemrox
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looking for handling information on TiCl4
I'm planning some reactions with TiCl4. Hydroaminations and reactions with alkynes and carbonyls. I want to know if I need a glove box and need to
handle it with a syringe? Is i reactive enough toward metals to pull some more Fe out of the stainless needle? (There's a percentage of FeCl3).
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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PainKilla
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TiCl4 is very reactive, but there are't any problems using it under a hood, or anywhere where you won't breathe in the fumes.
As far as using needles, they do tend to clog up after a few minutes but if you do a rapid transfer it's not at all problematic to use steel-tipped
needles.
[Edited on 25-4-2008 by PainKilla]
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not_important
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| Quote: | Originally posted by Dr. Beaker
...
It seems my only option to remove HCl is to freeze with liquid N2 and de-gas...
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Isn't LN2 a bit of overkill, as TiCL4 freezes at -25 C and HCl at -114 C
I've seen a purification of TiCl4 that used a bit of TiH2 to reduce some of the contaminating metals chlorides, which is not likely a problem in your
case, then anhydrous AlCl3 reflux, followed by an excess of NaCl and refluxing to form NaAlCl4, filtering and fractionating the TiCl4 from that,
followed by freezing using a bath of CCl4 + dry ice and pumping down to clear any HCl.
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12AX7
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| Quote: | Originally posted by not_important
Isn't LN2 a bit of overkill, as TiCL4 freezes at -25 C and HCl at -114 C |
*Cough*...old thread warning.
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Fleaker
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| Quote: | Originally posted by chemrox
I'm planning some reactions with TiCl4. Hydroaminations and reactions with alkynes and carbonyls. I want to know if I need a glove box and need to
handle it with a syringe? Is i reactive enough toward metals to pull some more Fe out of the stainless needle? (There's a percentage of FeCl3).
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I just used some titanium tetrachloride today. Had to break a self-made (by the TiCl4) seal of hydrolysis products with a stainless steel spatula. The
spatula was corroded by it (turned black) but the corrosion wiped off with a paper towel. It fumes horribly (comparable to thionyl chloride and PCl3).
You don't need a glove box, you just need to be quick about transferring it into a schlenk line.
I think you would be in the clear for using the needle for a few seconds. It is the HCl that attacks the stainless, probably not the TiCl4. Keep it
away from moisture.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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