Antwain
Hazard to Others
Posts: 252
Registered: 21-7-2007
Location: Australia
Member Is Offline
Mood: Supersaturated
|
|
What can these chemicals be used for?
I could have sworn I saw a thread about this before, but I can't find it now.
As part of a great package deal I just ended up buying a very random assortment of chemicals. For US$25 (+$20 p&h  ) I got:
triphenyl-isopropyl-phosphonium iodide,
potassium iodide,
saccarin, sodium salt hydrate,
CuCl (looks a bit 'atmosphered')
silicon metal (elemental really, but hey) 1g,
cobalt acetate( only 5g)
niobium petoxide ~16g (this was the main reason I bought it)
and zinc dust (clumpy and maybe also 'atmosphered')
What I cant see a use for is the phosphonium salt, the guy said in a blub that it is an 'isopropylating agent'; the saccarin; and the silicon....Im
sure I can find uses for everything else 
Also what can I do with a litre of polystyrene foam???
[Edited on 27-10-2007 by Antwain]
|
|
|
12AX7
Post Harlot
Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline
Mood: informative
|
|
Styrofoam is good for lost foam casting (to connect with an unreleated thread).
Tim
|
|
|
chloric1
International Hazard
Posts: 1071
Registered: 8-10-2003
Location: GroupVII of the periodic table
Member Is Offline
Mood: Stoichiometrically Balanced
|
|
If you are into purifying salts and such by crystallization, surround a hot vessel of your solution with the styrofoam will insulate it so it will
cool more slowly if you wish to obtain bigger crystals.
Fellow molecular manipulator
|
|
|
JohnWW
International Hazard
Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
I have heard of quaternary phosphonium salts with bulky aromatic groups, like that one, being used as catalysts. The Zn dust could be used for organic
reductions, especially in conjunction with acids to produce nascent hydrogen, and to make organozinc compounds similarly to organomagnesium compounds
such as Grignard reagents. The elemental Si, if you have a zone-melting furnace hot enough, could be used, with "doping" by Al, Ga, P, or As, to
produce semiconductors; or silicon carbide abrasive. The Co(II) and Cu(i) could be used to produce other complexes, especially for investigation as
organic catalysts. The KI could be reacted with chlorine or hypochlorite to produce elemental I2, to make certain drugs or organoiodine compounds, or
oxidized further to periodate(VII), of use in carbohydrate analyses for cleavage of vic-diols or vic-diketones. The Nb2O5 has some use as a catalyst,
similarly to V2O5 used in redox cycles as in H2SO4 manufacture. The saccharin, I suppose, could be used as a sugar substitute, although it has been
banned in Canada for that use; it consists of a benzene ring fused to a 5-membered saturated hetero-ring containing a secondary N atom bonded to a
hexavalent (sulfone) sulfur atom attached to the benzone ring, and a ketone C attached to the benzene ring; it, and especially N-substituted
derivatives e.g. with attached sugar groups, could be examined for possible use as antibiotics.
|
|
|
garage chemist
chemical wizard
Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline
Mood: No Mood
|
|
Look up the Wittig reaction (google) for a potential use for your quaternary phosphonium compound.
The niobium pentoxide is difficult to transform into other niobium compounds, is is a rather inert substance.
The only methods to get it into solution are fusion with NaOH or KHSO4 (first one forms soluble niobate, I dont know what the second one makes) and
dissolution in aqueous HF (happens readily, with formation of the complexes H2NbOF5 and H2NbF7).
In industry, this solution (HF extract of ore) is extracted with MIBK to separate Nb from Ta (Nb goes into the organic phase, Ta remains in the
aqueous one), the organic solution washed with H2SO4, the Nb back-exctracted from the organic phase with water and made alkaline with ammonia to
precipitate hydrous Nb2O5 which is fired to the oxide.
Niobium pentoxide can be reduced aluminothermically to the metal, however the reaction is not self-sustaining (not exothermic enough). The mixture is
therefore either preheated (e.g. the reaction is run in a furnace) or more Al and an oxygen-releasing compound are mixed in to deliver the necessary
heat.
Ullmann states that aluminium is used in excess in this reaction and the resulting Nb-Al alloy separated in a high-vacuum electron beam furnace by
melting (2497°C) the crude niobium, causing the Al and other metals to boil off completely.
NbCl5 is exclusively preparated from the elements at high temperature, or from Cl2 and ferroniobium instead of pure niobium.
Ferroniobium is prepared by co-reduction of niobium oxide ores and iron oxide with Al powder. Since the ore can be used directly (after concentration)
without extraction using chemicals, niobium should be significantly cheaper in the form of ferroniobium than as the element (although the cost of the
Al powder is surely also considerably contributing to the total cost of this process).
The commercially traded and used (additive in steelmaking)
ferroniobium contains 40- 70% niobium.
It might be worthwhile to make ferroniobium oneself, since the ferric oxide thermite provides the necessary extra heat for the Nb2O5 reduction, making
preheating or other oxygen carriers obsolete.
I plan on getting some niobium metal in the near or less near future and making NbCl5 from it (it would be hard to make NbCl5 starting from Nb2O5 at
home, due to the necessary intermediate production of metallic Nb. The aluminothermic reaction could probably be successfully performed at home if a
suitable furnace is built or the reaction mix modified as described above, but removal of aluminium would be impossible at home. I do not know how one
could separate AlCl3 and NbCl5 after chlorination of the alloy, they are chemically quite similar- both powerful lewis acids, and both soluble in
polar and nonpolar solvents like THF and benzene).
Perhaps someone knows the substances better and/or has an idea or can contribute? AlCl3/NbCl5 separation sounds tricky, it takes more knowledge about
the compounds than I have found in Ullmann.
Searching Ullmanns further, the solubility of anhydrous FeCl3 is low in hexane and benzene while that of NbCl5 is probably much higher. This could be
a method to separate the FeCl3/Nb2O5 mix from chlorination of ferroniobium (the sublimation temps of those two are too similar to allow efficient
separation by sublimation. (Sublimation temps: NbCl5: 250°C, FeCl3: 305°C, AlCl3: 181°C ).
Although NbCl5 might form a complex with those solvents which distills unchanged- I had this happen with AlCl3/toluene once, it is not possible to
reclaim the metal halide from such a complex!
Another idea would be to reduce the FeCl3 to nonvolatile FeCl2 with hydrogen at 200°C. NbCl5 sublimates at 250°C, so this would have to be done with
good temperature control and stochiometric amounts of hydrogen only. Or one could just sublimate the mix in a hydrogen stream into the hot tube and
let the reduction of the FeCl3 happen in the gas phase- sounds better.
Reduction of NbCl5 with H2 requires 600°C, so there is a big working margin for the FeCl3 reduction.
Finely divided Nb2O5 can also be reacted with thionyl chloride in a pressure tube at 200°C to directly obtain NbCl5- see Brauer, third book.
Why did I write so much? Because NbCl5 is a catalyst for the cyclization of acetylene to benzene, and I was reading up about niobium chemistry at the
moment I wrote this.
See the patent:
http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=GB961576&a...
Page 6, example 2. Deuterobenzene from deuteroacetylene.
Maybe this post should be moved to a thread more specifically about niobium and its chemistry so that it doesnt get lost.
[Edited on 28-10-2007 by garage chemist]
|
|
|
12AX7
Post Harlot
Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline
Mood: informative
|
|
What about the good old Cl + C reductive chlorination? Nb2O5 + 5C + 5Cl2 --(some hellish temperature)--> 2 NbCl5(g) + CO(g).
Tim
|
|
|
UnintentionalChaos
International Hazard
Posts: 1454
Registered: 9-12-2006
Location: Mars
Member Is Offline
Mood: Nucleophilic
|
|
A quick search shows that they do this with titanium oxides in a fluidized bed reactor at 900-1000C..I imagine that "some hellish temperature" would
be about the same (although I always figured that hell would be hotter than that...lakes of molten tungsten would be pretty cool). I don't think
anyone here is crazy enough to work with 1000C (pressurized?) dry chlorine gas...although who knows..but what ungodly device do you contain that in?
Having this article might be handy if you go the ferroniobium route: http://www.springerlink.com/content/k967k35v0074203t/
[Edited on 10-28-07 by UnintentionalChaos]
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
|
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
