angelhair
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TiCL3 made at home?
Is is possible to make Titanium lll chloride at home from OTC compounds?
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kilowatt
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Of course, you can make almost any chemical at home with OTC materials if you have the right apparatus and the time, knowledge, and patience. The
only exceptions are those that contain elements that are not available OTC, like highly radioactive ones. But is it practical? How badly do you need
it?
TiCl3 would be a tricky one, since it is made from TiCl4, which is itself made by the reaction of TiO2 (readily available) with carbon and dry
chlorine at something like 800°C or a dull red heat. TiCl4 is a volatile (liquid at STP) and corrosive chlorinating agent which reacts with water and
most acids to revert to TiO2 and HCl. To make TiCl3, TiCl4 is reduced with a metal such as aluminum. The mixed chlorides are then separated with
THF, which forms an air reactive complex with TiCl3, which should be handled in an inert atmosphere. The complex is then thermally decomposed to
afford pure TiCl3, which also is air reactive. Further heating decomposes TiCl3 to TiCl2 which is a powerful reducing agent, and chlorine.
The Land of the Free and the Home of the Brave... good joke
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angelhair
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yes I do have tha apparatus and the time. I thought there might be an easier way than the TiCl4 route. Thanks, I might try it anyway.
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kilowatt
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Well I imagine you would work "backwards" by chlorinating TiCl2, but that's not exactly OTC.
The Land of the Free and the Home of the Brave... good joke
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halogenstruck
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i made it easily before but the concentration can not reach high,only enough to see the pink-red color.
i mixed TiO2 with Al powder[very fine like flour][atomized,the kind which is used in painting] and aluminothermy by a red nichrom filament warmed by
electricity===>u have Ti sponge although alloyed with a little Al and mixed with Al2O3,TiO2,TixOy then sponge is reacted with KOH conc.===>then sponge
is treated with Conc. HCl and boiled with till turns to pink-red.
another method i can propose[i have not done this one by myself] is to heat TiO2/NaHSO4 and resulted dry containing TiO(SO4)
to be mixed with KCl and distilled dry ==>TiCl4,...
i read before in a book but cannot remember well.
something like this:
TiO2+H2SO4==dry heating==>TiOSO4==adding KCl==>K2TiCl6 precipitation==>precipitate to be distilled dry==>TiCl4
[Edited on 29-10-2009 by halogenstruck]
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blogfast25
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TiCl3 can be prepared in aqueous solution by simply dissolving Ti metal in conc. HCl. In reflux at BP this reaction (Ti + 3 HCl ---> TiCl3 + 3/2 H2)
is quite vigorous and fairly concentrated solutions can be obtained according my own experience. These deep blue/violet solutions are stable at low
pH and in the absence of air (or other oxidisers). I've done this quite a few times to assay home-made titanium.
Adding an excess NH4F to a TiCl3 solution should cause the complex (NH4)3TiF6 to form, which may be a route (via thermal decomposition) to TiF3.
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blogfast25
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Quote: Originally posted by halogenstruck  |
i mixed TiO2 with Al powder[very fine like flour][atomized,the kind which is used in painting] and aluminothermy by a red nichrom filament warmed by
electricity===>u have Ti sponge although alloyed with a little Al and mixed with Al2O3,TiO2,TixOy then sponge is reacted with KOH conc.===>then sponge
is treated with Conc. HCl and boiled with till turns to pink-red.
[Edited on 29-10-2009 by halogenstruck] |
You can improve that method by adding KClO3 + Al, to the TiO2/Al mix, as well as some CaF2 as a slag fluidiser. The added KClO3 + 2 Al ---> KCl +
Al2O3 generates enough heat (provided you add enough KClO3/Al stoichiom. mix) to obtain the reaction products (Ti metal + alumina, the KCl boils off)
in the molten state (and not as a sintered sponge) from which the metal then separates more or less neatly. Instead of KClO3 I've also used NaNO3 and
CaSO4 (adjust stoichiometries). BaO2 and KClO4 would probably also work: any oxidiser capable of oxidising Al to alumina.
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halogenstruck
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thx a lot for your answer,i tried to dissolve the Ti sponge in Conc. HCl but it dissolved very hardly.
it`s a good idea to use a flux,i didn`t think about that before.
i would be grateful if u explain what formulation u use and how much metal u prepare every time,have u ever analysed it quantitaviely?
it is a good idea if u add NiO to the mixture and make NiTi,nitinol,shape memory alloy, the molecular ratio is 1:1
[Edited on 2-11-2009 by halogenstruck]
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woelen
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First a comment on your language. Please use normal sentences, punctuation and words.
Back on topic, titanium metal dissolves slowly in conc. HCl, even when the metal is pure. I have a fine powder of titanium (99.7% purity) and even
that only very slowly dissolves, giving a deep blue/purple solution. On dilution this liquid becomes more purple. So, bulk metal will dissolve even
more slowly. Of course, heating speeds up the dissolving of the metal, but it is not sufficiently self-heating to keep it hot.
You can enhance the speed of dissolving the metal considerably if you add a small amount of NaF or NH4HF2 to the liquid. With fluoride added, even in
10% HCl the metal quickly and completely dissolves, giving a green solution (apparently some complex with fluoride is formed) and lots of hydrogen
gas. When the green liquid is oxidized by air it first becomes brown (mixed oxidation states +3 and +4) and finally it becomes colorless, when all
titanium has gone to oxidation state +4.
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blogfast25
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| Quote: Originally posted by halogenstruck |
it`s a good idea to use a flux,i didn`t think about that before.
i would be grateful if u explain what formulation u use and how much metal u prepare every time,have u ever analyse it quantitaviely?
it is a good idea if u add NiO to the mixture and make NiTi,nitinol,shape memory alloy, the molecular ratio is 1:1
|
You'll find the information on formulation and methodology on the thread immediately below (start from top):
http://www.sciencemadness.org/talk/viewthread.php?tid=10150#pid1208...
The overall best formulation was found to be (parts by weight):
TiO2 = 100 / Al = 72 / KClO3 = 61 / CaF2 = 47
I analysed the metal thus obtained quantitatively by dissolving a precisely known amount in simmering conc. HCl and titrating the solutions with
standard Fe3+ solution, using KSCN (thiocyanide) as an indicator.
Ti3+ + Fe3+ ---> Ti4+ + Fe2+, endpoint is red due to formation of FeSCN2+.
This gave me an assay of about 80 % Ti on the acid-soluble part of the metal, the rest is mainly alloyed Al.
It should be possible to reduce the amount of alloyed Al by increasing the ratio of TiO2:Al from the stoichiometric 1:4/3 (= 3/4) to perhaps 1:1,
thereby pushing TiO2 + 4/3 Al ---> Ti + 2/3 Al2O3 to the right, but I haven't studied that yet.
Another contributor here had his thermite Ti analysed with EDX (X-ray fluorescence) and obtained roughly the same result, if you bear in mind that the
metal also contains some 10 - 15 % acid insoluble residue, mainly fine, annealed Al2O3 (slag):
http://www.sciencemadness.org/talk/viewthread.php?tid=10249&page=17...
It's possible to obtain binary (and more complex) alloys such as ferrotitanium (FeTi) by combining the oxides. In the case of the ferrotitanium alloy,
if you get the ratio of Fe2O3/TiO2 right, no additional KClO3 is needed because the 'Classic Thermite' (Fe2O3 + Al) part of the formulation produces
the heat needed to reach melting point. That worked very well for me.
This should be possible also using NiO but NiO has the drawback of being a monoxide:
NiO + 2/3 Al ---> Ni + 1/3 Al2O3, so it produces only 1/3 of a mole of alumina per mole of NiO, as opposed to KClO3 (or Fe2O3) which produces 1 mole
of alumina per mole of KClO3 (or Fe2O3).
For a nickel titanium alloy with a Ti:Ni molar ratio of 1:1 the formulation would be (in moles):
TiO2 >>>>> 1 mole
NiO >>>>>> 1 mole
KClO3 >>>> x mole
Al >>>>>>> 4/3 + 2/3 + 2x mole
CaF2>>>>> y mole
Here x would have to be calculated so that the total amount of alumina formed would be close to the amount of alumina produced by the straight
TiO2/KClO3 formulation. y is calculated by maintaining the ratio of CaF2/Al the same as in the straight TiO2/KClO3 formulation... Such a TiO2/NiO
formulation would yield about the same heat of reaction.
[Edited on 2-11-2009 by blogfast25]
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blogfast25
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| Quote: Originally posted by woelen |
Back on topic, titanium metal dissolves slowly in conc. HCl, even when the metal is pure. I have a fine powder of titanium (99.7% purity) and even
that only very slowly dissolves, giving |
Well, how long is a piece of string?
For my standard Ti3+ solutions, I dissolved 1" x 1/4" bars of 99.9 % Ti bought from ebay. At steam bath temperatures and using about 30 % HCl the
reaction is very vigorous but it still takes a few hours to reach about 0.1 M concentration.
If you add an alkali to the solution, a black precipitate of Ti(OH)3.3 H2O (?) or Ti2O3.n H2O (?) forms which oxidises immediately to TiO2 by means
e.g. added hypochlorite (bleach).
Never tried the fluoride trick, I would have expected the TiF6 (3-) complex (assuming that's what it is) to be colourless.
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woelen
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If I add e.g. 500 mg of titanium powder to 5 ml of concentrated HCl and I do not apply heat, then it takes several hours before all of it has
dissolved. The resulting solution then is dark blue/purple. Indeed, when alkali is added, a black precipitate is formed. The black precipitate is so
strongly reducing that small bubbles of hydrogen are formed inside the precipitate, it reduces water. Slowly, the precipitate turns white, even
without adding an oxidizer like bleach.
More info and pictures can be found here: http://woelen.homescience.net/science/chem/solutions/ti.html
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blogfast25
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| Quote: Originally posted by woelen | If I add e.g. 500 mg of titanium powder to 5 ml of concentrated HCl and I do not apply heat, then it takes several hours before all of it has
dissolved. The resulting solution then is dark blue/purple. Indeed, when alkali is added, a black precipitate is formed. The black precipitate is so
strongly reducing that small bubbles of hydrogen are formed inside the precipitate, it reduces water. Slowly, the precipitate turns white, even
without adding an oxidizer like bleach.
More info and pictures can be found here: [url]http://woelen.homescience.net/science/chem/solutions/ti.html |
[/url]
Yes, heat is everything.
I didn't allow the black precipitate to stand, so I didn't see the bubbles.
But several of my Ti3+ solutions, now over a year old and once a nice deep blue, have completely cleared up, despite having been stoppered
hermetically. This is more true of those kept on my lab bench (where they get some direct light) than of those kept in my lab cupboards.
Presumably they have slowly oxidised but there is no TiO2 precipitate, so they must contain TiOCl2.
There's something slightly strange about this: nascent hydrogen swiftly reduces TiO2+ solutions to Ti3+, as you know we do this by adding some Al or
Zn to the acid titanyl solution, the evolving hydrogen reduces the Ti from +IV to +III.
With the black precipitate and my TiCl3 solutions the opposite occurs: here H +I is reduced to H 0 by Ti +III...
[Edited on 3-11-2009 by blogfast25]
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