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MidLifeChemist
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Has anyone dissolved Titanium Dioxide?
I was able to procure some TiO2 cheaply from one of the pottery websites in the USA (no surprise there!)
Has anyone *personally* tried to dissolve Titanium Dioxide? If so, how did it go? I've read the literature extensively, including Woelen's excellent
website.
From what I've read in the preparatory inorganic handbook, it *may* dissolve slowly in very hot conc. sulfuric acid (or HF / molten NaOH, neither of
which I want to work with).
My ultimate goal is to reduce it to Ti+3.
Woelen's website pretty much says doing this is futile. Just wanted to see if anyone had success.
Thanks in advance.
I'll report my findings when and if I try it.
[Edited on 21-9-2020 by MidLifeChemist]
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symboom
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I do not have experience desolving it but I looked up reactions involving titanium dioxide which is natoriously stable
I did find this which involved a reaction without having to reduce titanium dioxide in the traditional sence
Oxide-iodide exchange from aluminium iodide.
3 TiO2 + 4 AlI3 → 3 TiI4 + 2 Al2O3
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Bedlasky
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For preparation of Ti3+ is better metallic titanium.
Maybe zinc in HCl can reduce TiO2 in to TiCl3? But I am not sure about that, this is only idea.
Fussing TiO2 with NaHSO4 leads to TiOSO4, which is soluble in cold water (in hot water hydrolyse in to TiO2 and H2SO4).
TiO2 is also soluble in hydrogen peroxide, forming orange complex. But this isn't good starting point for Ti3+, because hydrogen peroxide is oxidizing
agent.
I personally never try anything of these, because I already have titanium metal which can be easily dissolved in conc. HCl. I bought 100g of titanium
powder for 6,5$.
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MidLifeChemist
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Bedlasky, thanks for the information.
Perhaps in the future I'll spend the extra money for the Titanium metal powder, I agree that would be a better approach. But it's about $27 for Ti
powder in the USA including shipping, and the TiO2 was only $2.75 
I have zinc, HCL, and 3% H2O2, so I'll try all 3. I also have NaHSO4 but I'm not sure how high of a temperature you have to heat it to. All will be
interesting experiments!
Quote: Originally posted by Bedlasky  | For preparation of Ti3+ is better metallic titanium.
Maybe zinc in HCl can reduce TiO2 in to TiCl3? But I am not sure about that, this is only idea.
Fussing TiO2 with NaHSO4 leads to TiOSO4, which is soluble in cold water (in hot water hydrolyse in to TiO2 and H2SO4).
TiO2 is also soluble in hydrogen peroxide, forming orange complex. But this isn't good starting point for Ti3+, because hydrogen peroxide is oxidizing
agent.
I personally never try anything of these, because I already have titanium metal which can be easily dissolved in conc. HCl. I bought 100g of titanium
powder for 6,5$. |
[Edited on 21-9-2020 by MidLifeChemist]
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Endo
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For analytical work on sunscreens with TiO2 it usually involved ashing in a platinum crucible followed by dissolving the TiO2 out of the ash using HF.
We had issues getting very good recovery using sulfuric acid at high heat but a decent portion did make it in solution, just not 100%. If you are up
for a bit of loss of relatively cheap chemicals maybe you could try this route.
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MidLifeChemist
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| Quote: Originally posted by Endo |
We had issues getting very good recovery using sulfuric acid at high heat but a decent portion did make it in solution, just not 100%. If you are up
for a bit of loss of relatively cheap chemicals maybe you could try this route.
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Yeah, I'm game for the fun, cheap route. I don't mind losing some TiO2.
With H2SO4, how high of heat do you think I need to go to?
thanks
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symboom
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TiO2 is also soluble in hydrogen peroxide whaaat that does not seem possible
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Bedlasky
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Why not? Ti(IV) forms soluble peroxide complexes. This reaction is used for spectrophotometric determination of Ti.
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Bedlasky
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| Quote: Originally posted by MidLifeChemist | Bedlasky, thanks for the information.
Perhaps in the future I'll spend the extra money for the Titanium metal powder, I agree that would be a better approach. But it's about $27 for Ti
powder in the USA including shipping, and the TiO2 was only $2.75
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I understand, TiO2 is quite cheap. Try to look on ebay if there is Ti powder for more reasonable price.
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WGTR
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I have dissolved it in molten sodium bisulfate that’s used as “pH down” that you can get from a big box hardware store. You can try this
yourself by melting some in a test tube (use a fume good or good ventilation), and dissolve bits of titanium dioxide until nothing more dissolves.
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MidLifeChemist
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>> Try to look on ebay if there is Ti powder for more reasonable price.
Thanks! Yeah I always check Ebay, I can get 50 grams from India for $11... maybe I'll order some down the road or see if another options comes up
later
>> I have dissolved it in molten sodium bisulfate that’s used as “pH down” that you can get from a big box hardware store. You can try
this yourself by melting some in a test tube (use a fume good or good ventilation), and dissolve bits of titanium dioxide until nothing more
dissolves.
Thanks, I'll have to give that a try. I do have some NaHSO4.
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unionised
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| Quote: Originally posted by MidLifeChemist | Bedlasky, thanks for the information.
Perhaps in the future I'll spend the extra money for the Titanium metal powder, I agree that would be a better approach. But it's about $27 for Ti
powder in the USA including shipping, and the TiO2 was only $2.75
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It doesn't need to be powder.
Offcuts of Ti from metalworking are cheaper.
It's a bit slower but... what's the rush?
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MidLifeChemist
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You make a good point. 225 grams of shavings on ebay are $13 including shipping. I might go that route if the TiO2 routes all lead to dead ends. It
will be fun trying though.
| Quote: Originally posted by unionised |
It doesn't need to be powder.
Offcuts of Ti from metalworking are cheaper.
It's a bit slower but... what's the rush? |
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woelen
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TiO2 is very inert. You can get it dissolved, but only in molten salts like NaHSO4. You need quite strong heating. Not something I like. Probably hot
(nearly boiling) H2SO4 at 300+ C also works.
TiO2 may dissolve in solutions with H2O2, but this reaction is very slow and you get an orange peroxo-species. This species has a very strong color
and even a very dilute solution has quite a strong yellow color. I never tried this myself, but I have severe doubts that you will get decent (useful)
quantities of Ti, dissolved in water.
Metallic Ti really is the way to go. It easily dissolves in HCl, giving a beautiful indigo/purple solution.
I also noticed, that there are differences in inertness of samples of metal oxides. This has to do with the heating-history of the sample. A sample,
which has been heated for a long time or at higher temperatures, is more inert than other samples.
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MidLifeChemist
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>> You can get it dissolved, but only in molten salts like NaHSO4
Thanks Woelen - I appreciate your reply and I did carefully read the Titanium page on your excellent website. I agree, none of the options look that
attractive. do you think even 3% H2O2 would dissolve it slowly? I'll be giving that a try this weekend.
But yet for now, I have some cheap TiO2, and i'm not in a hurry to buy the metal. But I have no doubt that eventually I'll give in an buy the metal as
that indigo/purple solution sounds too alluring.
If I do manage to get some "dissolved", do you have any advice on how I can get it reduced down to Ti+3? I was going to try Zinc Powder + HCL.
I have no doubt that my sample will fall into the category of maximum inertness, lol.
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Arthur Dent
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My source for nice, clean titanium in ample quantity is an old, defunct powerBook G4 Titanium, of which I removed the titanium outer case and cut it
up in strips. If you have such a computer at home, there's your source for Ti 
PS: It was long dead so no big loss. Anyway, the G4 processor is so obsolete as to be completely unusable for anything but a doorstop.
--- Art is making something out of nothing and selling it. - Frank Zappa ---
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unionised
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| Quote: Originally posted by MidLifeChemist |
If I do manage to get some "dissolved", do you have any advice on how I can get it reduced down to Ti+3? I was going to try Zinc Powder + HCL.
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The best reducing agent is metallic titanium + acid.That way you don't introduce any other metals.
:-)
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MidLifeChemist
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Yes, of course the best option is what I don't have, lol.
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woelen
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If you manage to get some titanium dissolved in its +4 oxidation state, then you could try HCl + zinc. You have a good chance that you get (part of)
it reduced. Keep in mind though, that the amount of zinc in the solution will be many times as large as the amount of titanium(III). Using zinc as
reductor is not my favorite thing. You usually get lots of hydrogen, and just a little of the desired product. But this method can be useful. Several
experiments with titanium in aqueous solution do not suffer from the presence of the colorless zinc ions.
If you get the titanium in solution with H2O2, then you have the added complication that you first have to decompose all of the H2O2, before any
titanium can be reduced to its +3 oxidation state. H2O2 immediately oxidizes any Ti(3+) to titanium(IV).
Indeed, try to get some metallic titanium powder.
This may also be useful: https://www.ebay.com/itm/50mm-x-165mm-0-5mm-Recycled-Metal-T...
It's a used cathode. For your purpose it mosat likely is perfectly fine. If it is of no use, then you only lose a few bucks. Just immerse it in conc.
HCl and be patient. After a few hours you will have a nice purple solution.
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MidLifeChemist
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Ok, I just bought the last 2 of them for sale. Only $5, not bad! Thanks for the link, and for the additional tips.
If nothing else, I'll have some fun trying to dissolve / reduce the TiO2 while waiting for the Ti metal.
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MidLifeChemist
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UPDATE: the two Titanium anodes arrived today. Not bad, 10 days from China via speedpak (which has awesome tracking), and shipping was only $2 !!!!
The mesh is sharp though I have to be a little careful handling them
total weight of both of them is just under 20 grams.. that should give about 2 ounces of TiCl3, more than enough for some experiments..
Any predictions how long it will take one to dissolve in 32% HCL?
Woelen, thanks again for the link.
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Bedlasky
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Don't dissolve it at once. Ti3+ is air sensitive and it will slowly oxidize in to TiO2.
Just put it in to concentrated HCl and place it on hot water bath. After a hour or so you will get nice very dark blue solution which can be used for
experimenting.
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MidLifeChemist
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Back to TiO2? Oh my god, Titanium Dioxide is such a menace! Thanks for the tip.
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xxxxx
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I read in an old chemical technology book that titanium dioxide was soluable in ethylamine and that this was how it was extracted from it's ore back
in the day.
So I contacted a manufacturer of ethylamine and they confirmed that titanium dioxide is soluable in ethylamine, about 25 grams per liter (presumably
at 20 degrees Centigrade) and that the solution conducts electricity.
Titanium dioxide is a covalent molecule and it is probably forming a compound with the basic ethylamine like carbon dioxide reacts with water to form
carbonic acid.
I was interested in whether titanium dioxide would be soluable in liquid anhydrous ammonia and other amines such as tert-butylamine and
ethylenediamine and if the solubility might increase at higher temperatures.
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clearly_not_atara
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Lactic acid can attack TiO2 and forms a soluble complex IIRC. You probably want finely powdered titania, strong lactic acid solution, and high
temperature.
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