Baphomet
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NiO > NiCH3COO
This seems like a very simple task, but I cannot seem to make any Nickel salts, let alone acetate. The Nickel Oxide I'm using is the green one, not
the black one.
Following were tried and had no effect. The substance is one tough s.o.b.:
- Refluxing in GAA
- GAA and H2O2 30%
- Sulphuric Acid 98%
- HCl 30%
- Heated with a blowtorch (glowed but did not change!)
Can anyone recommend something?? Thanks!
\"Who ARE you? You\'re like the drummer from REO Speedwagon - nobody knows who you are\" from \'Employee of the Month\'
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Jor
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If it doesn't dissolve in boiling HCl, it is probably calcined like many pottery chemicals are and is inert to attack from acids.
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turd
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Dunno... But have you tried the usual suspects, that is a melt of one of the following:
* KHSO4
* K2S2O7
* Na2CO3/K2CO3
* Na2CO3/S
?
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woelen
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I agree with Jor, there is a good chance that the material is calcined and many metal oxides in lower oxidation states (+1, +2, +3) become amazingly
inert when they are calcined. They change to a microcrystalline state which does not react with anything, except the most corrosive things, such as
molten NaOH.
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Magpie
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How much nickel salt do you need? I prepared a prepared a small amount of Ni(NO3)2 from pure nickel and 6N HNO3.
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Nicodem
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Have you tried dissolving that nickel oxide in aqueous ammonia?
Sometimes oxides and other metal compounds that are inert to dissolution in acids, dissolve in solutions containing proper ligands (like ammonia,
cyanide, hydroxide, phosphate, etc.). Don't expect anything fast if the material is calcinated (as it appears to be).
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scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
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Elawr
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Have you tried fusing it together with some NaHSO4? In the molten state this salt can dissolve some things that won't otherwise. Maybe this would give
you NiSO4 which is very soluble.
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woelen
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I have read that NiO can be converted to Ni2O3.nH2O by heating it in moist air (or even better in moist oxygen) for a prolonged time. The flame should
not be directed to the material, but on the crucible, which contains the material. The color changes from green to black in this process. It is
important that water is present in this process. Anhydrous Ni2O3 does not exist, a hydrated form will form. The Ni2O3.nH2O can be more easily
dissolved in acids, but still, this requires heating for some time in boiling moderately concentrated HCl.
You also could try converting it to some Ni(III) species by boiling it with a solution of KBrO3 or a solution of NaOH to which some elemental bromine
is added. Again, the NiO should turn black. The Ni(III) species then can be used to release the nickel in soluble form.
[Edited on 10-5-09 by woelen]
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Baphomet
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Thanks to all of you for your suggestions. I just tried 25% Ammonia but it had no effect.
Woelen I will try heating in moist air as you recommend. In fact after reading your post I found the following online:
http://www.uq.edu.au/_School_Science_Lessons/topic12F.html
"Heat some nickel carbonate in a hard glass test-tube and note the green-brown residue of nickel (II) oxide. Heat the nickel (II) oxide in a
crucible and black nickel (III) oxide, Ni2O3, forms. Dissolve nickel (III) oxide in dilute sulfuric acid to give green nickel (II) sulfate."
First time I tried there was no water.. this time I will use the blowtorch and add some water to the powder first.
\"Who ARE you? You\'re like the drummer from REO Speedwagon - nobody knows who you are\" from \'Employee of the Month\'
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turd
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If that doesn't help, you really should try the different melts proposed. That's the tried and tested old-school method. The one problem I see is
choice of the correct crucible. we usually use Pt-crucibles (of course not if there's S or oxidizers involved) and I'm not sure what a good
replacement might be.
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woelen
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This is exactly the reason why I am not fond of such high temperature chemistry at all. Glass cannot be used, it simply is too risky and many of these
melts are highly alkaline and these simply chuck away the glass. Most metals give impurities and then you end up with a mess which needs purification
afterwards and the few crucibles which would be suitable are unaffordable. The only one might be nickel, which seems to be fairly resistant against
alkaline melts, but these also are hard to get and expensive.
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zed
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AlCl3 might work. Reaction conditions? Don't rightly know.
But, the reaction 3NiO + 2AlCl3----->3NiCl2 + Al2O3, would figure to be pretty irreversible.
Of course, NiO would also probably react in a thermite type reaction with Al metal.
In which case you would end up with Al2O3 + Ni metal.....Or possibly, a crater.
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madprossor
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Quote: Originally posted by Baphomet  |
"Heat some nickel carbonate in a hard glass test-tube and note the green-brown residue of nickel (II) oxide. Heat the nickel (II) oxide in a
crucible and black nickel (III) oxide, Ni2O3, forms. Dissolve nickel (III) oxide in dilute sulfuric acid to give green nickel (II) sulfate."
First time I tried there was no water.. this time I will use the blowtorch and add some water to the powder first.
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unfortunately notes were lost but i can verify that this method works fine. some Nickel Carbonate (light green in color) was heated in a pyrex dish
in a kiln with no additional water for 4 hours. i don't remember the exact temperature, 1000F maybe, 537C? nickel oxide black is produced, which i
thought was a mixture of NiO and Ni2O3. your reference suggests your NiO green should work just the same.
anyway, the nickel oxide black produced from the carbonate reacted just as well with AcOH at reflux as some commercially purchased nickel oxide did.
it takes about 30 minutes for complete conversion with good stirring. the Nickel Acetate can then be vacuum filtered. then it should be dried and
crushed with gentle heating, in a dessicator if desired.
anyone else familiar with the use of bleach/NiAc to generate Nickel Oxide Hydroxide in situ, a useful oxidizer? the amount of nickel required is
catalytic and the reaction medium is water. it is comparable to TCCA/tempo on some substrates...
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bbartlog
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I've heard of using Ni(Cl)2 this way (comes to the same thing since either of them forms the oxide hydroxide). In fact I believe that was one of the
first papers I downloaded from here. DCM also works as a solvent. Anyway yes as I recall it has wide application, you can oxidize primary alcohols to
carboxylic acids and secondary alcohols to ketones, benzyl alcohol to benzoic acid and so on. Though if you want aldehydes I think it's less useful
since it wants to go all the way to carboxylic acids.
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madprossor
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it would be nice if someone would give me access to said downloads area...
you're right either NiCl2 or NiAc can be used according to my ref.
http://pubs.acs.org/doi/abs/10.1021/jo0612574
i was wanting to make a carboxylic acid and looking for a better alternative to jones reagent. is it as easy to prepare NiCl2 as the acetate? i
think NiCl2 is needed for Urishibara catalyst, so it would be nice to have that from OTC also.
[Edited on 13-3-2010 by madprossor]
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dann2
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| Quote: Originally posted by woelen | | I agree with Jor, there is a good chance that the material is calcined and many metal oxides in lower oxidation states (+1, +2, +3) become amazingly
inert when they are calcined. They change to a microcrystalline state which does not react with anything, except the most corrosive things, such as
molten NaOH. |
Just wondering if you were to ball mill a calcined metal Oxide would that make it more susceptible to attack from acids?
Dann2
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arsen
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Nitric acid is usually the best acid for dissolving Nickel compounds.
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chemoleo
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Thread Moved
17-4-2010 at 06:45 |
blogfast25
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Thermite it!
NiO + 2/3 Al --> Ni + 1/3 Al2O3
I haven't got the Heat of Formation of NiO but I believe it's not very high (similar to CoO and CuO), in which case the reaction will be highly
exothermic. Always add a good dollop of CaF2 flux/coolant.
Then dissolve the Ni metal in acid.
In fact, for NiO just found: HoF (25 C) = - 244.3 kJ/mol
For Al2O3: HoF (25 C) = - 1669.8 kJ/mol
For NiO + 2/3 Al ---> Ni + Al2O3
Heat of Reaction (25 C) = 244.3 - 1/3 x 1669.8 = - 312.3 kJ/mol
... which may well be enough to vaporise the contents of the crucible (unless you add Fluorite as heat sink/flux)!
Yum, yum, nice little reguli of pure nickel metal...
[Edited on 17-4-2010 by blogfast25]
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