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deltaH
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Titanium nitrate
According to [1] from the wiki on titanium nitrate, a hydrated titanium tetranitrate can be formed by reaction of the oxide with conc. nitric acid.
Unfortunately, this is all it says... no conditions, no description of the form of TiO2 used. 
The question of conditions is posed in the researchgate thread [2], whereby it is indicated that boiling conc. nitric acid should be used, but again,
no details, no references.
I'm specifically wondering if one refluxes TiO2 powder in an excess of 65% nitric acid, could you dissolve it and ultimately recover Ti(NO3)4.4H2O by
boiling down and then crystallising by cooling? I am worried about hydrolysis back to TiO2 that was suggested to be a problem.
There are also many types of TiO2 powders commercially available, I take it using brookite is out because of it's extreme inertness as suggested by
[3], where it is also suggested that HF is added to accomplish the dissolution of anatase or rutile... obviously something one would want to avoid if
possible 
A final complication I want to mention is that titanyl nitrate, TiO(NO3)2, can also be prepared and this is not desired.
Does anyone have experience with trying to dissolve TiO2 powders in nitric acid?
References:
[1] Wiberg, Egon; Wiberg, Nils (2001). Inorganic Chemistry. Academic Press. p. 1331.
[2] http://www.researchgate.net/post/Formation_of_Titanium_Nitra...
[3] http://www.inorganicventures.com/samples-containing-titanium
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blogfast25
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Despite occasional (erroneous in my view) references to the contrary, I firmly believe Ti(NO3)4 does not exist.
The small size and high charge of "Ti<sup>4+</sup>" makes this ion extremely prone to hydrolysis:
[Ti(H2O)6]<sup>4+</sup> + H2O === > [Ti(OH)(H2O)5]<sup>3+</sup> + H<sub>3</sub>O<sup>+</sup>
...and subsequent deprotonating steps.
Most grades of TiO2 are also far too inert for direct dissolution in acids, although some grades do dissolve in boiling 100 % H2SO4 upon prolonged
treatment. Fusion with NaHSO<sub>4</sub> also works.
In aqueous media, Ti (IV) only exists as TiO<sup>2+</sup>(probably solvated).
TiO(NO<sub>3</sub> <sub>2</sub> (titanyl nitrate) would be
best prepared as follows, IMHO. Precipitate Ti(OH)<sub>4</sub>.nH<sub>2</sub>O from a titanyl sulphate solution with ammonia.
Filter off precipitate and wash carefully.
IMMEDIATELY re-dissolve precipitate in an excess of pure HNO3 (65 % should also work). Precipitates of titanium hydroxide ('titanic acid', LOL) age
very quickly, converting to the far less soluble TiO<sub>2</sub>. Working quickly is essential.
Whether a solid TiO(NO<sub>3</sub><sub>2</sub> hydrate can
be isolated from this I do not know. It is certainly very likely to highly hygroscopic.
[Edited on 2-2-2015 by blogfast25]
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deltaH
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Thanks blogfast, I suspected you would reply what with your experimentation with titanium chemistry. It is indeed a nice curiosity
and I am also sceptical and was even surprised to learn of this compound.
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blogfast25
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Quote: Originally posted by deltaH  | | Thanks blogfast, I suspected you would reply what with your experimentation with titanium chemistry. It is indeed a nice curiosity
and I am also sceptical and was even surprised to learn of this compound. |
Look also at the element below: zirconium. 'Straight' Zr(IV) compounds are rare and hard to keep. The halides are essentially polarised covalent
compounds.
What passes for "Zr(NO3)4" (e.g.) is almost certainly already adulterated to more basic forms in most cases. A Zr(SO4)<sub>2</sub> hydrate
does appear to exist. Zirconium is of course a larger atom and its ions have lower central electrical field strength.
[Edited on 2-2-2015 by blogfast25]
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deltaH
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Yet it is claimed that the nitrate groups are coordinated to the central atoms bidentately AFAIK, but now I can't remember where I read that... maybe
mixed up with zirconium.
What started me out with this is looking for cheaper alternatives to ammonium hexanitratocerrate(IV), aka CAN. Like a good chemistry boy, I remembered
that compounds of one element diagonally up and to the right of another are sometimes similar, so looked at the periodic table and saw that for the
lanthanides, this would be zirconium, then I read about zirconium nitrate and indeed it appeared to be exactly this and could form polynitrato
complexes like the lanthanides, i.e. what I was searching for. Then I thought I'd check up on titanium nitrates because zirconium isn't exactly super
cheap and Bobs your uncle!
Incidentally, somewhat similar to 'cerric ammonium nitrate', it is claimed in the wiki on zirconium nitrate that zirconium indeed forms a
cerric-ammonium-nitrate-like complex where lots of nitrates coordinate to the metal, namely (NH4)Zr(NO3)5.HNO3 [1]. Isn't that remarkable? I suspect
that titanium is too small to form such complexes with extra nitrates though and I could also not find literature on it.
References
[1] Morozov, I. V.; A. A. Fedorova; D. V. Palamarchuk; S. I. Troyanov (2005). "Synthesis and crystal structures of zirconium(IV) nitrate complexes
(NO2)[Zr(NO3)3(H2O)3]2(NO3) 3, Cs[Zr(NO3)5], and (NH4)[Zr(NO3)5](HNO3)". Russian Chemical Bulletin 54 (1): 93–98.
*******
Yes the bidentate coordination was indeed for titanium tetranitrate, blogfast, please have a look at those wiki articles (for
titanium nitrate and zirconium nitrate). They describe the crystallography of those compounds, so I don't think there can be any doubt as to their
existence and what form they're in.
[Edited on 2-2-2015 by deltaH]
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blogfast25
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| Quote: Originally posted by deltaH | Yes the bidentate coordination was indeed for titanium tetranitrate, blogfast, please have a look at those wiki articles (for
titanium nitrate and zirconium nitrate). They describe the crystallography of those compounds, so I don't think there can be any doubt as to their
existence and what form they're in.
|
Can you link to the specific articles in Wiki, in particular relating to titanium(IV) nitrate?
Only if it contains external and authorative references would I trust Wikipedia in this instance, BTW.
+++++++++++++++++
And a side note on zirconium's cost. 'Technical' powdered zircon (ZrSiO<sub>4</sub> can be bought cheaply from pottery shops (or <i>moi</i>
intended as opacifier in glazes and extracting the Zr from there is child's play (fuse with excess KOH, hydrolyse frit, dissolved in strong HCl to
separate ZrOCl<sub>2</sub> from silica). Easy peasy.
Roll-on antiperspirant deodorants also contain significant amounts (10 - 15 % at least) of an Al/Zr/glycine chloride complex and the Zr can be
extracted and separated from the Al quite easily.
Both methods have been described by me on the pages of this loony/'kewl'/don't know what I'm talking about/can't spell-won't spell bin.
Search or ask. In neither case has the Zr been de-hafnified, of course (two for the price of one!)
Zirconium is a highly interesting element and much under-appreciated on these here pages. Not sure why...
[Edited on 3-2-2015 by blogfast25]
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deltaH
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Okay! So won't be writing off Zr then.
[1] & [2] look most interesting for titanium nitrate, I could pop off a request in publications if necessary...
References
From the Wiki on titanium nitrate:
[1] Garner, C. D.; S. C. Wallwork (1966). "The crystal structures of anhydrous nitrates and their complexes. Part III. Titanium(IV) nitrate". Journal
of the Chemical Society A: Inorganic, Physical, Theoretical: 1496.
[2] C. C. Addison C. D. Garner W. B. Simpson D Sutton, S. C. Wallwork (November 1964). "The Structure and Reactivity of Titanium(iv) Nitrate; and NO3
Radical Mechanism for Oxidation by Bidentate Nitrate Groups". Proceedings Chemical Society: 367.
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blogfast25
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This bidentate Ti(NO3)4 (which undoubtedly exists) isn't comparable to ionic Ti(NO3)4, so we had our wires crossed.
I mean, a nitrate that is fairly volatile at RT, dissolves in CCl4 and nitrates aromatics?
From the Wiki entry:
| Quote: | | Titanium III (Ti3+) reduces nitrate ions to ammonium, so titanium (III) nitrate does not exist.[13] |
... I found very interesting.
[Edited on 3-2-2015 by blogfast25]
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deltaH
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That still leaves my original question largely unanswered though. Does Ti(NO3)4.4H2O exist and can a more reactive form of titania be dissolved in hot
conc. nitric acid to form it?
I've phoned the local rep for Evonik, they produce an industrial fumed titania nanopowder called AEROXIDE TiO2 P25. Used to know it as just P25 back
in the day when using it as catalyst support. It's a mixture of anatase and rutile. We used to also use as a reagent to prepare TS-1 and titanium beta
silicalites, albeit in fluoride media, in a sol-gel method. These were zeolite-like structures without aluminium but containing titanium, for
oxidation catalysts. As commercial products go, this is probably the most likely to dissolve in hot nitric acid. Your suggestion of fusing TiO2 with
an acid salt and then freshly precipitating with ammonia would no doubt have the best chance, but I would like to avoid the fusion step. I might want
to scale this up someday if something useful comes of it
Anyhow, the rep is trying to organise a sample for me. Crossing fingers.
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blogfast25
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I don't believe "Ti(NO3)4" would 'survive' water, even if your P25 does dissolve in 100 % nitric acid. Whether it will dissolve in that will strongly
depend on temperature: the BP of pure HNO3 is only 83 C e.g., a drawback in this case.
I explained the reason above (hydrolysis).
In the wiki entry, the tetra hydrate doesn't even get a CAS number (weak evidence, I know).
I'd be very interested in how you get on with all this, so please keep me posted here.
[Edited on 3-2-2015 by blogfast25]
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deltaH
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Absolutely, will do.
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deltaH
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Good and bad news: my Evonik P25 fumed titania (titania nanopowder) arrived today (thanks Evonik!), but I've also finally gotten published conditions
for the preparation of titanium(IV) nitrate hydrate. Yup, looks like blogfast was right on the money, it's made from titanium
hydroxide and not the oxide as stated in other literature. Worse, it requires fuming nitric acid
| Quote: | The hydrated nitrate of titanium(1v) was prepared by dissolving
hydrated titanium hydroxide in fuming nitric acid and evaporating the solution to
dryness; the hydrated hydroxide was obtained by precipitation with aqueous ammonia from a
solution of titanous chloride. |
from Field, B. & Hardy, C. (1963).
Fortunately, as stated earlier by blogfast, the prep of titanium hydroxide could be done by neutralising titanyl sulfate with ammonia
instead of the chloride.
I don't mind performing a fusion so much, but I do mind the fuming nitric acid, I'm not kitted to prepare that 
Sigh... I could always add enough 98% H2SO4 to tie up the 35% water content of that as H3O+, that might prevent hydrolysis of the titanium nitrate and
since that is a coordination complex, might even cause it to precipitate the anhydrous version, which would be very nice.
Thought's blogfast?
Reference:
Field, B. & Hardy, C. (1963). 1006. Volatile tetranitratotitanium(IV): preparation, infrared spectrum, and reaction with saturated hydrocarbons.
J. Chem. Soc., pp. 5278-5281.
*Available in the usual place.
[Edited on 6-2-2015 by deltaH]
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blogfast25
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| Quote: Originally posted by deltaH |
Fortunately, as stated earlier by blogfast, the prep of titanium hydroxide could be done by neutralising titanyl sulfate with ammonia
instead of the chloride.
I don't mind performing a fusion so much, but I do mind the fuming nitric acid, I'm not kitted to prepare that
Sigh... still searching for a more amateur friendly way of making this stuff. Perhaps electrolysing freshly etched titanium anodes in ~65% HNO3?
Thought's blogfast?
|
Of course TiOCl<sub>2</sub> would work as well as TiOSO4, that goes w/o saying.
Methods of obtaining a TiO<sup>2+</sup> solution:
Fuse P25 with NaHSO4. On cooling dilute carefully to desired concentration. Weigh any undissolved TiO2 for correction to
[TiO<sup>2+</sup>].
Ti powder dissolves quite easily in boiling 50 % H2SO4 to Ti(III) sulphate. Oxidise carefully in very acidic conditions with H2O2.
Freshly prepared "Ti(OH)4" probably dissolves also in 70 % HNO3. Keep temperature lowish (to prevent conversion to TiO2), filter off any undissolved
Ti(OH)4.
Whether the desired Ti(NO3)4.4H2O can be isolated from such a solution I do not know.
[Edited on 6-2-2015 by blogfast25]
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deltaH
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Sounds good, my intentions exactly. Thanks for the advice.
BTW: ever tried fusing with NaOH and then acidifying to obtain titanium hydroxide? I could use NaOH/KOH eutectic which melts much lower.
[Edited on 6-2-2015 by deltaH]
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Shivachemist
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Can I have the references for the aforementioned points? Of course, without your lecture this time :p
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blogfast25
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| Quote: Originally posted by deltaH | Sounds good, my intentions exactly. Thanks for the advice.
BTW: ever tried fusing with NaOH and then acidifying to obtain titanium hydroxide? I could use NaOH/KOH eutectic which melts much lower.
|
I used pure KOH in large excess. Works too. It's described somewhere on this board.
But the fusion with NaHSO4 from my experience you can carry out in an Erlenmeyer on a max heat hotplate. Takes a while though.
If by the 'aforementioned points' are meant my points, they are based on personal experimental experience, mostly reported on this forum. Search and
yee shall find.
If every time someone asks you for a reference there's going to be a little storm in a teacup, things are gonna get tedious very quickly.
[Edited on 6-2-2015 by blogfast25]
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Shivachemist
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Do they have photo or video evidence?
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deltaH
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The hotplate, is cough cough... uhm... a bit of a problem. I do have a gas stove that should work just fine though  On a side note, I have ordered a cheapie mag stirrer with temperature probe from
China, but unfortunately, being a cheapie, it only goes up to 100C and will also probably take another month+ to arrive, what with the Chinese new
year and all.
Shivachemist, usually, the only time references are asked for is when something seems to go against conventional wisdom or is simply
so interesting that you want to know more. You should not be offended by such requests when they're within reason.
[Edited on 6-2-2015 by deltaH]
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blogfast25
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| Quote: Originally posted by deltaH | The hotplate, is cough cough... uhm... a bit of a problem. I do have a gas stove that should work just fine though On a side note, I have ordered a cheapie mag stirrer with temperature probe from
China, but unfortunately, being a cheapie, it only goes up to 100C and will also probably take another month+ to arrive, what with the Chinese new
year and all.
Shivachemist, usually, the only time references are asked for is when something seems to go against conventional wisdom or is simply
so interesting that you want to know more. You should not be offended by such requests when they're within reason.
[Edited on 6-2-2015 by deltaH] |
Bunsen? You'll need 400 C or better for either fusion.
Stop acting like a stupid pr*ck.
[Edited on 6-2-2015 by blogfast25]
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deltaH
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Yes I'll try to get one or alternatively purchase a butane torch from the hardware store, depending on which is cheaper. I fear my stove flame is too
diffuse to really hit high temperatures, unless a very small sample is used.
[Edited on 6-2-2015 by deltaH]
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Bert
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YOU KIDS!
DON'T MAKE ME COME UP THERE!!!
Can everyone please play nice?
Thanks-
(Closes door, goes back to trying to figure out how to use DMSO solution of azodicarbonamide to coat/impregnate grains of double base propellant)
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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blogfast25
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delta:
Keep posting any progress. Close to my heart, this subject.
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deltaH
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Absolutely. I also thought I'd past this excerpt from the paper by Field, 1963 as it's so dramatic:
This is for the anhydrous version, which I'm not after, however, it is most impressive nevertheless.
Reference:
Field, B. & Hardy, C. (1963). 1006. Volatile tetranitratotitanium(IV): preparation, infrared spectrum, and reaction with saturated hydrocarbons.
J. Chem. Soc., pp. 5278-5281.
[Edited on 7-2-2015 by deltaH]
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blogfast25
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Your reference shows again that anh. Ti(NO3)4 does things the hydrate could never do.
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deltaH
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I'm absolutely blown away by this, how many reagents do you know that can rapidly functionalise aliphatic hydrocarbons at room temperature? There's a
large research centre of excellence in South Africa that has an entire multi-university division dedicated to activation of hydrocarbons. They mostly
look at enzymatic routes, but nothing would come close to this IMHO. The downside is the cost of these reagents though, unless a cheap way can be
found to regenerate everything in a closed loop so that only oxygen, hydrocarbons are feeds in a big black box drawn over the whole process.
[Edited on 7-2-2015 by deltaH]
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