Author Topic: Recycling PdCl2 (aka. just another reason to use DMF)  (Read 256 times)

Oerlikon

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Recycling PdCl2 (aka. just another reason to use DMF)
« on: August 13, 2010, 12:15:53 AM »
I have discovered something by accident in last night dream that might save you guys a lot of money!

If you use DMF as solvent/reaction media for Wacker you can VERY simply recycle
VERY expensive PdCl2!

After you are done with reaction use ordinary coffee filter and filter rxn contents.
There will be only a little filter cake, it is PdCl2 with some organic impurities.

Now wash it from the filter to the test tube, along what was left on the bottom of the baker.
Use acetone as the solvent.

Fill the test tube almost full of acetone, shake and let it settle.
Decant dark impure acetone (use syringe), let only last cm or so.

Fill it again, shake it, repeat the procedure at least 5 time.

You will have very pure PdCl2 left on the bottom after few washes.

You can now dry it and reuse it again. Works 100% for me!
I obtained more than 120g of ketone from recycled dried PdCl2 from 2 previous runs.

I was sloppy and recovered cca. 50%, but I am sure you can recover almost everything that didn't dissolve.
And make sure to dry it on the watch glass or something since it reacts with some metals.

I used acetone since it is cheap, dissolves all Wacker organic crap and doesn’t seems to dissolve PdCl2 much, if any.

This procedure works only with DMF as solvent and pure reactants(works great with bound_doublebound method p-benzo),
I think it is almost impossible to reuse it after MeOH synthesis, since there is
a lot of crap in the filter cake, but who knows...
Feel free to experiment like I did...
Try use different solvents, chill rxn contest and than extract etc.
Whatever you do just share it with others!

I know it might be very hard for you guys in EU and USA to find DMF, but it is worth money and effort!

I obtained mine as solvent for "old plastic models restoration".
It was used in the past as fast paint penetrator for some kind of now absolute plastic,
try in restoration institutes, art stores ,hobby shops etc.
Just UTFSE and make your own story!
I think it is almost impossible to reuse it after MeOH synthesis, since there is
a lot of crap in the filter cake, but who knows...
Feel free to experiment like I did...

I know it might be very hard for you guys in EU and USA to find DMF, but it is worth money and effort!

I obtained mine as solvent for "old plastic models restoration".
It was used in the past as fast paint penetrator for some kind of now absolute plastic,
try in restoration institutes, art stores ,hobby shops etc.
Just UTFSE and make your own story.
« Last Edit: September 20, 2011, 08:07:28 AM by Enkidu »
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lugh

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Re: Recyclig PdCl2 (aka. just another reason to use DMF)
« Reply #1 on: August 13, 2010, 12:13:58 PM »
There's also US3210152 which was posted on the Hive long ago:

http://www.erowid.org/archive/rhodium/chemistry/palladium.chloride.txt

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« Last Edit: August 13, 2010, 05:56:44 PM by lugh »
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Dunecat

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reusable PdCl2 (wacker oxidation)
« Reply #2 on: September 20, 2011, 03:58:21 AM »
I have been looking at the wacker oxidation reaction to change safrole to MDP2P. It seems quicker and more feasible than other routes that involve isomerization of safrole and etc to obtain MDP2P. What would really make this reaction brilliant would be a reusable catalyst, or a way of reclaiming most of the PdCl2 catalyst used in the reaction. This isn't a huge issue considering he value of the yielded products, but ordering this product from overseas will take time and a fair amount of capital; I think a reusable catalyst should be thought up.

To the best of my understanding, after the completion of the reaction, the hydroquinone and PdCl2 products are left behind after MDP2P has been removed via filtration. The thing that immediately springs to mind is exploiting solubility differences to seperate the two compounds. With the finicky properties of Pd compounds though, this might not work.

The other thought would be buying PdCl2 plated mesh or PdCl2 on some other unreactive substrate that could be reused many times before it had to be replaced. This would be quite cost efficient, with PdCl2 now going for around $30/g excl shipping. Does the catalystic need to be fully dissolved within solution for this to work?

If there's a thread on this subject I would love to be directed to it, but I didn't manage to find anything after several searches.

Thoughts, ideas, it'll all be appreciated.

RoidRage

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Re: reusable PdCl2 (wacker oxidation)
« Reply #3 on: September 20, 2011, 04:07:31 AM »
Recycling PdCl2 (aka. just another reason to use DMF)
http://127.0.0.1/talk/index.php/topic,1264.msg14199.html#msg14199

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akcom

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Re: Recycling PdCl2 (aka. just another reason to use DMF)
« Reply #4 on: October 03, 2011, 02:17:05 AM »
Solid support palladium catalysis, now that'd be slick.  I'd really be surprised if industrial bees aren't using something like that.  Palladium is definitely the limiting reagent when cost comes into play.  Not recovering it is just foolish.

uchiacon

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Re: Recycling PdCl2 (aka. just another reason to use DMF)
« Reply #5 on: October 04, 2011, 02:30:19 AM »
Solid support palladium catalysis, now that'd be slick.  I'd really be surprised if industrial bees aren't using something like that.  Palladium is definitely the limiting reagent when cost comes into play.  Not recovering it is just foolish.

Yes this was what I was thinking, but is the reaction catalyzed by Pd ions of the PdCl2 salt itself? I'm not sure if you dissolve the PdCl2 in DMF when you do the wacker oxidation, but when MeOH is used, it is said that yields are higher when the PdCl2 is "dissolved".

It wouldn't be that hard to find a chinese outfit on a trade website to make you a PdCl2 coated Ti mesh/sponge or something, but the PdCl2 would need to be completely insoluble in the solvent you're using.

akcom

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Re: Recycling PdCl2 (aka. just another reason to use DMF)
« Reply #6 on: October 04, 2011, 02:41:34 AM »
I'm thinking more a silicone or synthetic polymer bound ligand or something to that extent.  That way solubility isn't such an issue.
« Last Edit: October 04, 2011, 02:46:00 AM by akcom »

Oerlikon

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Re: Recycling PdCl2 (aka. just another reason to use DMF)
« Reply #7 on: October 04, 2011, 11:54:23 AM »
Why are you people asking questions AFTER it has been answered?!
Just read the first post in the thread!
Use DMF,chill postz rxn mix,suction filter it and you will have most of your PdCl2 on the filter paper.
There is no that much room for improvement here...
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Enkidu

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Re: Recycling PdCl2 (aka. just another reason to use DMF)
« Reply #8 on: October 04, 2011, 04:30:13 PM »
^ I merged the threads together