guy
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NiO catalyst for burning NH3
Is it possible to have NiO as a catalyst for burning ammonia? I read that nickel(II) oxide can be a useful catalyst for oxidation.
The theorectical reaction that I came up with is:
20NiO + 5O2 --> 10Ni2O3
4NH3 + 10Ni2O3 --> 4NO + 6H2O + 20NiO
Any Ni(NO3)2 will decompose to NO2 and NiO.
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guy
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Does nickel oxide easily form Ni2O3? I've read that nickel (II) oxide is green to black. I've also read that nickel(III) oxide is black. P.
Patnaik's Handbook of Inorganic Chemicals that NiO is green to black, and the black form occurs when it is heated strongly and has a slightly higher
oxygen content. Could that be Ni2O3?
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Fleaker
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The forms of nickel oxide that I am familiar with (from pyrolyzing nickelous nitrate) is greyish black. The nitrate salt however, is strongly green in
color.
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mick
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There is a lot of numbers in the equations and if heat is needed the reaction might go without the Ni.
NH3 is highly flammable in air, conc aqueous NH3 is flammable, conc aqueous NH3 and H2O2 gives a nice steady stream of O2 and I would think that is
highly flammable.
I have not tried it but I would think that under controlled conditions water and NO could be produced as the main products, there could be some
residual NO2 though.
mick
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Nerro
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I am absolutely positive that Cr2O3 will work.
NiO, FeO and CuO seem like worthy contestants.
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guy
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I have just finished preparing the NiSO4, and I want to convert to the oxide. I don't have nitrate or nitric acid so I can't turn it the nitrate. I
can convert it to acetate, but will that decompose to the oxide? Is it possible to get good absorption on the catalyst support using an insoluble
salt such as NiCO3?
And also, what should I use for the suport, silica gel or zeolites?
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Fleaker
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Ok, I have done something very similar to this, at least with respect to catalyst application. I used a ceramic heat resistant blanket as my substrate
(kaowool is the brand name) since it is basically mullite, an inert ceramic material. Also, it has very high surface area; picture putting your
catalyst mixture onto cotton candy, since that is what this stuff is most similar to in appearance. It served my purposes well, but if it comes down
to it for you, I would use zeolite rather than silica gel. I wouldn't recommend turning the salt into the acetate salt because when you go to heat it
up, some of the carbon in the compound could actually reduce some of the nickel oxide back to nickel metal. I also believe that using the insoluble
salt, (in your case, the carbonate) would greatly reduce the effectiveness of not absorption, but rather, adherence to your 'support'.
My best advice would be to make the nitrate salt if you can, after that's been decomposed, you will have the trivalent oxide of nickel as a chief
product. If, however, you find another method that produces only NiO, I suggest you heat the resulting oxide in a strongly oxidizing atmosphere.
U2U if you'd like to talk more.
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guy
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I made a catalyst tube out of a steel piple (about 6 inches) and some other parts(connecters, etc). I tried fine steel wool as the substrate. I am
using CuO now(I did some research and found that it is more effective). So I basically plated copper on the wool, and it quickly oxidized to CuO in
air. I stuffed the wool in the pipe and heated it until it was dried. Then I connected it to a filter flask with a stopper that had a hole where an
tube connected to an air pump was inserted. The gas outlet was connected to the tube. The flask is filled with 10% ammonia solution (with added
(NH4)2SO4). I don't have a bunsen burner or a propane burner. I use a butane portable stove like this one. I turned the gas all the way up. (The energy output listed on the site is 1,980kcal/h). The tube did not glow red on the outside. I saw
it glowed red on the inside for a second then stopped. No NOx gas was seen. Is it because the temperature is not high enough? Has anyone had sucess
with this experiment? Thanks.
[Edited on 5/20/2006 by guy]
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neutrino
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There is a chemistry demo that uses heated copper wire to catalyze the pyrolysis of ammonia into NOx.
From http://mattson.creighton.edu/NH3/index.html
| Quote: | | In this experiment we will use a coil of copper wire. Construct a coiled copper wire as shown in Figure 2 by winding a 30 cm length of 20 gauge
copper around a glass stir rod or pencil. The coils should be close to one another...heat the coiled portion of the wire at the top of the flame's
inner cone until it glows brightly red. Remove the coil from the flame and quickly start to discharge the gas mixture at ‘point blank’ range to
the red hot copper (but not touching it). The coils will glow as the wire catalyzes the reaction. The heat given off from the reaction maintains the
copper at red heat. More than one attempt may be necessary before this works properly. |
It looks like your tube simply isn't getting hot enough for the reaction to take place. Try getting it hotter with a stronger flame source and / or
good insulation.
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guy
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What would be a good heat source other than a propane burner?
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The_Davster
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You could run the tube through a furnace, or go with oxy acetylene torch or something.
Keep in mind that with a copper pipe, heat will be conducted away from the flame area where it will be cooled by the air. A shorter length of pipe
might be better.
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Fleaker
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Perhaps you could set the whole thing in some sort of charcoal brazier. The charcoal will serve both to insulate and to heat the system.
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guy
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Would electrical heating be more efficient? If so, can anyone describe in detail how to make an electrical heating thingy.
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guy
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Temperatures greater than or equal 800K are needed to generate NOx. Is a charcoal brazier or a cooking stove hot enough? I can not get any kind of
torch or burner now.
Source
http://alexandria.tue.nl/extra3/proefschrift/boeken/9803814....
[Edited on 5/22/2006 by guy]
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Fleaker
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Yes, 800K is realistic with charcoal. Temperatures approaching 2000K/1720C are possible with forced air blast (hence melting iron!)
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guy
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And so to make charcoal that temperature, I need charcoal in a flower pot, lighter fluid and fire? Do I need additional air for 800K? Thanks
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12AX7
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Probably not.
Leave room for the drain hole in the bottom too.
Tim
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