Sciencemadness Discussion Board - Has anyone dissolved Titanium Dioxide?

Has anyone dissolved Titanium Dioxide?

MidLifeChemist - 21-9-2020 at 08:58

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]

symboom - 21-9-2020 at 09:38

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

Bedlasky - 21-9-2020 at 09:51

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$.

MidLifeChemist - 21-9-2020 at 10:08

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]

Endo - 21-9-2020 at 10:21

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.

MidLifeChemist - 21-9-2020 at 10:49

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.

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

symboom - 21-9-2020 at 11:21

TiO2 is also soluble in hydrogen peroxide whaaat that does not seem possible

Bedlasky - 21-9-2020 at 12:33

Quote: Originally posted by symboom

TiO2 is also soluble in hydrogen peroxide whaaat that does not seem possible

Why not? Ti(IV) forms soluble peroxide complexes. This reaction is used for spectrophotometric determination of Ti.

Bedlasky - 21-9-2020 at 12:37

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

I understand, TiO2 is quite cheap. Try to look on ebay if there is Ti powder for more reasonable price.

WGTR - 21-9-2020 at 12:48

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.

MidLifeChemist - 21-9-2020 at 13:25

>> 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.

unionised - 22-9-2020 at 04:10

Quote: Originally posted by MidLifeChemist

It doesn't need to be powder.
Offcuts of Ti from metalworking are cheaper.
It's a bit slower but... what's the rush?

MidLifeChemist - 22-9-2020 at 05:22

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?

woelen - 23-9-2020 at 23:17

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.

MidLifeChemist - 24-9-2020 at 07:37

>> 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.

Arthur Dent - 24-9-2020 at 08:05

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.

unionised - 24-9-2020 at 08:28

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.

The best reducing agent is metallic titanium + acid.That way you don't introduce any other metals.

:-)

MidLifeChemist - 24-9-2020 at 08:54

Quote: Originally posted by unionised

The best reducing agent is metallic titanium + acid.That way you don't introduce any other metals.

:-)

Yes, of course the best option is what I don't have, lol.

woelen - 24-9-2020 at 23:33

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.

MidLifeChemist - 25-9-2020 at 05:44

Quote: Originally posted by woelen

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 most 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.

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.

MidLifeChemist - 6-10-2020 at 04:52

Quote: Originally posted by woelen

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 most likely is perfectly fine. If it is of no use, then you only lose a few bucks.

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.

Bedlasky - 6-10-2020 at 06:05

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.

MidLifeChemist - 6-10-2020 at 07:24

Quote: Originally posted by Bedlasky

Ti3+ is air sensitive and it will slowly oxidize in to TiO2.

.

Back to TiO2? Oh my god, Titanium Dioxide is such a menace! Thanks for the tip.

xxxxx - 22-1-2024 at 18:52

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.

clearly_not_atara - 23-1-2024 at 09:15

Lactic acid can attack TiO2 and forms a soluble complex IIRC. You probably want finely powdered titania, strong lactic acid solution, and high temperature.

maldi-tof - 12-5-2024 at 12:39

HCl and digestion using microwave.
At least that is what I remember a company used for analysis of TiO2 via ICP -OES