[Platinum]

I have searched among patents and works on Internet after a preparation of anhydrous Raney Nickel, but can't find more than one case where they used n-Butylamine, which subsequently was dried in an inert atmosphere. This doesn't seem rational for more general purposes.

I have been thinking of washing the Raney Nickel with 99,95% < methanol (this alcohol because it's much easier to prepare this almost anhydrous), at the same time as a strong magnet is holding the suspension down. I was thinking of repeating this decantation several times, and I expect the solid to become pretty anhydrous. I've heard this from other sources, that this gives a "pretty anhydrous" solid. I would like to know how anhydrous in % this is expected. The latter is maybe a very hard question to answer, because there are several factors involved. Still, I give it a try; maybe someone has dealing with this issue before.

How anhydrous is it possible to reach by this washing-method?


I'm very thankful for a really qualified answer.

[discodermolide]

No idea. But do a Karl-Fischer water determination of one of the methanol washes.

[Platinum]

No idea. But do a Karl-Fischer water determination of one of the methanol washes.

Absolutely, a very accurate method. I was actually suspecting that maybe some water still remains in the Ni, and not equal to that in the methanol.

However, thank you for answering.

[discodermolide]

Do traces of water really mater?

[curiouscat]

I was actually suspecting that maybe some water still remains in the Ni, and not equal to that in the methanol.

Could you see if there is a weight loss on sustained drying in an inert gas atmosphere? Would need a lot of accuracy though.

[Platinum]

Do traces of water really mater?

Not really if it's only traces. In 1 L solution I'm allowed to have maybe 1 g of water. The solvent can I prepare to under 0,05% water content, which is 0,5 g water. The catalyst of 50 g must then contain maximum 0,5 g water, which is 1%. I don't know if less than 1% water in the Raney Nickel is realistic.

Could I maybe warm the catalyst in xylene, at 120 C? I guess all of the water would leave at this temperature probably over maybe one or two hours...

[discodermolide]

You could do that.
Less than 1% water is certainly realistic. Try the azeotrope with toluene, be careful it does not *Ignore me, I am impatient* over or you will get the Cat. all over the place.

[OC pro]

What do you want to do actually? Dry Raney-nickel is highly highly pyrophoric.

[Platinum]

You could do that.
Less than 1% water is certainly realistic. Try the azeotrope with toluene, be careful it does not *Ignore me, I am impatient* over or you will get the Cat. all over the place.

Ok, maybe I can use the Dean Stark trap to determine the water content with toluene, as well as remove the water. Nice idea.

I will be very, very careful when handling this catalyst.