RareEarth
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Does letting Raney Nickel burn deactivate it?
If I take some Raney Nickel and let it dry out and ignite, will letting it burn its course effect its activity at all, for say, transfer
hydrogenations? I'm thinking it burns as a result of residual H2 leftover from its preparation, and during transfer hydrogenations the hydrogen never
really leaves the reagents so the nickel won't really become reflameable. As long as the Nickel is still in its Nickel 0 form, shouldn't it still be
active?
edit
Or a better alternative, what if I put the raney nickel under a vacuum to draw out the hydrogen?
[Edited on 2-4-2015 by RareEarth]
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Nicodem
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Am I missing something, or are you truly asking if your Raney nickel will still be OK after you destroy it?
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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RareEarth
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I was under the impression that Raney Nickel is not "more active" because there is stored hydrogen in it, but rather because it has a very high
surface area due to the porous aluminum matrix. I would be supplying the hydrogen source (via formate salt, IPA, or some other donor) during the
reaction, so I don't see how letting the hydrogen burn out is 'destroying it'.
So am I missing something?
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gdflp
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The hydrogen isn't the only thing which is flammable. Even Raney Nickel which hasn't been hydrogenated is pyrophoric as are most fine mesh transition
metal powders. After burning, you will be left with nickel(II) oxide along with aluminum oxide and other metal oxides present in the original alloy.
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Dr.Bob
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Burning it will make nickel oxides and ruin it.
Most chemists simply store it under water, as it is normally shipped, and once used, they simple take the dregs and put them in a waste jar under some
water, until the jar is full of solids. But if you were reusing the nickel there is no reason that you could not simply pour off the reaction and
then rinse the Raney nickel with water (maybe some ethanol mixed in, then a few more times with pure water) to clean it and then simply leave it under
water for storage. Kinda like phosphorus.
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