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Topic: Solvents for KMnO4 to be used as an oxidizing agent  (Read 11282 times)

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Offline curiouscat

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Solvents for KMnO4 to be used as an oxidizing agent
« on: September 23, 2013, 07:28:03 AM »
What are good solvents for KMnO4 to be used as an oxidizing agent? My substrate is a water immiscible liquid and the idea is to see if reaction rates can be hastened by using an organic dissolved KMnO4 (as opposed to a water solution).

KMnO4 seems unstable in many typical solvents.

Ideas?

Offline discodermolide

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #1 on: September 23, 2013, 07:30:26 AM »
Try a phase transfer catalyst and stir like hell.
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Offline antimatter101

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #2 on: September 23, 2013, 07:44:47 AM »
Get a crown ether like 18-crown-6, quadternatery ammonium salt, and some benzene/pyridine solvent (derivatives also work) and mix them all together. Add your KMnO4 right after, and stir. It should completely dissolve.

You never used crown ethers in your entire life? That's disappointing.

Offline curiouscat

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #3 on: September 23, 2013, 08:16:20 AM »
You never used crown ethers in your entire life? That's disappointing.

Sadly true.

But thanks for the tips.

Offline curiouscat

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #4 on: September 23, 2013, 08:16:49 AM »
Try a phase transfer catalyst and stir like hell.

Thanks @disco!

Offline discodermolide

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #5 on: September 23, 2013, 08:32:20 AM »
I think crown ethers may be too expensive for curious, and too toxic. I think he is really large scale!
Phase transfer cats. are certainly cheaper and easier for him to handle.
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Offline curiouscat

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #6 on: September 23, 2013, 08:36:24 AM »
I think crown ethers may be too expensive for curious, and too toxic. I think he is really large scale!
Phase transfer cats. are certainly cheaper and easier for him to handle.

My bad. Yes, @disco brings up an important point that I always forget to mention:

This isn't a lab prep but an intended commercial process  with target volumes of several tens of tons per month of a not-very-high-value product (~$5-7 / kg).

So, yeah, can't really go for very fancy / nasty or expensive ingredients.

Offline discodermolide

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #7 on: September 23, 2013, 09:12:22 AM »
Several tons per month, now that is a decent scale!
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Offline curiouscat

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #8 on: September 23, 2013, 09:26:52 AM »
Several tons per month, now that is a decent scale!

tens of tons....   ;)

Offline discodermolide

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #9 on: September 23, 2013, 09:33:04 AM »
Even better, tons is small scale stuff.
At least you see what you get, more than can be said for the poor Academics with their mgs!
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Offline curiouscat

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #10 on: September 23, 2013, 10:01:57 AM »
At least you see what you get, more than can be said for the poor Academics with their mgs!

One reason I switched tracks after my post doc.  :)

Most of  the stuff I do is quite low brow science not of any fundamental interest though.



Offline discodermolide

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #11 on: September 23, 2013, 10:07:05 AM »
Must be of interest to someone with tens of tons a month.
Anyway high or low brow it's still interesting and each has its own particular problems.
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Offline curiouscat

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #12 on: September 23, 2013, 10:10:05 AM »
Must be of interest to someone with tens of tons a month.
Anyway high or low brow it's still interesting and each has its own particular problems.

True! Thanks for your tips as always. I'm going to try some TBAB / Aliquat. Might be challenging finding a PTC that KMnO4 won't oxidize away.

Offline discodermolide

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #13 on: September 23, 2013, 10:53:04 AM »
May make TBAB permanganate?
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Offline antimatter101

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Re: Solvents for KMnO4 to be used as an oxidizing agent
« Reply #14 on: September 24, 2013, 07:54:21 AM »
-18-crown-6 solvates the potassium ion in KMnO4 while the quad. ammo. salt solvates the MnO4- anion, basically.

If the crown ether is that expensive, then don't buy it. (My recommendation) Instead, why not make some yourself? You could use Williamsom ether synthesis, though chances are there will be multiple products.

Toxicity can be handled with some antidote (if possible), some PPE, and a fume hood. In factories people carry around hydrofluoric acid while whistling, and people almost never get hurt. Why so afraid of crown ethers?

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