Lion850
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Did I accidently make Titanium tetrachloride?
I was going to try and make Titanium Triiodide. I reacted 2g of Titanium foil (broken into small pieces) and 8g Iodine crystals with Dichloromethane
for about an hour with the DCM boiling but there did not seem to be any reaction (DCM boils at under 50 deg C). I then though to use Xylene as solvent
to achieve a higher reaction temperature. I did not want to waste the 8g Iodine as I am running low, and started reading up on mixing DCM and Xylene.
From what was said on Google these solvents can be mixed, so I added 100ml Xylene to the 60ml DCM (which was dark-black purple due to the dissolved
Iodine). I then boiled this for an hour. I don't know the temperature achieved but it was much higher then before, I could not touch the beaker
anymore. After an hour there was no sign of any color change and off-gassing of Iodine vapour was not reducing so I decided to stop. Plan was to
filter the solution, clean and weight the leftover Titanium to see if any was consumed, and then re-use the solution to make another metal Iodide. At
this point I started to notice a different smell - it had a slight bite to it, like acid. When I did the filtration the funnel started to fume with a
pale 'steam' as did the beaker collecting the filtrate. I then saw the beaker that was used for the initial reaction, that was now empty and from
which I removed the Titanium for cleaning, had a yellowish color on the sides and was also fuming! Spraying water into the beaker resulted in a smudge
of light brown deposit. This fuming continued when the contents was at room temp (probably 30 deg in my shed today, and quite humid). Unfortunately I
did not take a photo I just wanted to get rid of this fuming mess. I poured sand into a big plastic container, poured the still fuming filtrate into
it, also the filter paper, then some sodium thio sulphate, and the wash water after washing the beakers. No more fumes coming out of the container so
I put on the lid loosely - in case it wants to build up pressure.
Afterwards I realised the fuming I saw can be explained by the presence of Titanium tetrachloride. When I weighed the Titanium foil pieces afterwards
it varied between 1.8 and 1.9 gram, so if any Ti was consumed it was only a gram or so.
What else could have caused the fuming of the beakers apart from TiCl4?
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Tsjerk
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TiI4 and water form HI which fumes and smells like HCl.
I would try again in dry xylene, excess titanium and see if you can get the reaction to completion. The color of said compound is dark red/black, but
maybe you can still determine the end point by color.
[Edited on 28-11-2019 by Tsjerk]
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Lion850
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Hi Tsjerk - That does not explain the fuming from the filtrate and funnel as at that point no water was added? But, the humidity is quite high here
today.
I need to have a think and re-do the reaction, but preferably using Titanium powder to get a faster reaction rate. Which I do not have at the
moment....
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Tsjerk
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I guess you are doing this in a reflux setup, you could put a drying tube on top and let it go for half a day or so insulated with some aluminum foil.
The less iodine you use the faster the reaction will be finished, excess titanium can easily be filtered off, TiI4 boils at over 300 so you can
distill of the xylene.
You don't need much moisture to make these compounds fume..
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Lion850
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Sadly no proper reflux....just a round bottom flask with ice water sitting on top of the beaker. Works quite well with xylene hardly any losses in
solvent, all condenses and drips back, but probably impossible to keep sealed. I must look into reflux apparatus.
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Tsjerk
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And what about putting a stopper in the round bottom and putting it in a cupboard for a couple of weeks? Or at least until you have a reflux
condensor?
With xylene and a drying tube a 30 cm air condensor probably suffices. Maybe with a small fan pointed at it.
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unionised
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An active aromatic hydrocarbon like xylene.
An alkyl halide like DCM and
An Lewis acid catalyst like TiI3
Sounds like a recipe for a friedel Craft reaction.
That would (slowly) produce HCl as a by product and that would dissolve in the mixture.
It might react with Ti to give TiCl3 or TiCl4
Or it might just outgas.
Either way, you could get fumes in moist air.
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unionised
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Quote: Originally posted by Tsjerk  | | And what about putting a stopper in the round bottom and putting it in a cupboard for a couple of weeks? |
If I'm right, the stopper blows out, or the flask bursts from HCl or H2 production.
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Tsjerk
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I meant the xylene/I2/titanium reaction, no DCM involved here.
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clearly_not_atara
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Ti metal is very reactive when depassivated, SEP -1.63 for Ti2+ <> Ti which is comparable to the SEP for Al or compare Zn at -0.73. So I would
not rule out a reaction with DCM when I2 is present to activate. I also would not be surprised if Lewis acid activation stimulates DCM reactivity
towards Ti as well as towards xylene, the former generally being more reactive. Plus, I- can undergo Finkelstein substitution with DCM.
Overall, I would not suggest using activated titanium and DCM in the same flask for any reason other than to start a fire.
[Edited on 29-11-2019 by clearly_not_atara]
[Edited on 04-20-1969 by clearly_not_atara]
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