dormouse (Member)
04-23-00 05:18
No 108759
      benzo wacker secrets -hellman     

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Author  Topic:   benzo wacker secrets 
Member   posted 07-21-99 08:47 PM          
This is as novel as it gets,
A FOAF of mine, loved the benzowacker, as its results were much good.
He had ran it sucessfully numerous times, but just this once, he thought it was time to change the solvent,
His hatred of purchasing this product(DMF), made him feel anxious and controllably sick inside..blah,blah..
Controllably, yes, ultimately his mind was in controll of his body,.
What shit, sorry, its that bud...

So he had two solvents laying around,
100% Ipa and 100% xylene, and some dmso, (which he hasn't been tried yet.)
He understood, as far as he thought the mechanism's of a good solvent,.

Do you know what happened when he substituted with these 2 solvents.

Yes, He now no longer feels controllably sick any more.


He doesn't mind so much with the P-benzo, as he has a genuine interset in photography chemicals.

Hypothetically speaking, I believe DMSO will work (2).


unregistered   posted 07-21-99 08:52 PM           
Wow, man, yor the best,
and hey.. I'm sorry for that shit in the aquisition post,.
Darn problem is. I'm basically fucked from speed, And dad never really hug me that much,
sorry man


Member   posted 07-21-99 11:09 PM          
Real nice work bro.
What ratio IPA to Xylene?

unregistered   posted 07-22-99 07:46 PM           
hellman, impressive.
made me wonder whether or not 100% acetone substituted for 100% IPA might not improve the process even further by not interfering with the oxidation process, though.

Methyl Man
Member   posted 08-01-99 11:55 AM          
Hellman, come on back now, this is unresolved. Those who dig the benzo wacker could really benefit from this info.
Are you saying that one can substitute either IPA [i]or[i/] xylene instead of DMF, or are you saying one can use a mixture of those two in some proportion (please give the ration if it's the latter).

thanks brother bee

Penis Seinfeld
Member   posted 08-01-99 01:25 PM          
WHAT THE FUCK!!!! That is not me up there!!!
Why the hell would you want to impersonate me?



rev drone
Member   posted 08-01-99 07:38 PM          
Um, well... This isn't as novel as it gets, actually.
The Wacker oxidation has been done many times in MeOH, EtOH, iPrOH, DMF, DMSO, etc. As for alcohols interefering, this isn't much of a problem. Yes, Pd2+ species can catalyze alcohol oxidation, but not significantly under the conditions you're likely to encounter when oxidizing olefins. For that matter, they catalyze the Bayer-Villiger RxN, if you let them, but to date, that hasn't been a problem.

Barring olefins or amines from usage as solvents, the only practical limitations here really regarding solvent choice is the solvent's ability to dissolve both the catalyst(s) and reagents. Fer crissakes, using a PTC and the right ligands on palladium, you can actually even get away with even less than THAT -- by dissolving the olefin and PdCl2 in something like DCM, and adding an aqueous layer of H2O2, then a PTC to shuttle the oxidizing species from the aqueous phase into the organic phase, you can successfully perform the Wacker in an ultra-clean cutting-edge way (ref's available upon request.)

No yields, reaction time, conditions, concentrations, general observations, or even molar proportions with your report? No mention of the solubility of your catalysts in your solvents system, or the actual proportions of the two solvents, for that matter? You didn't even tell us what catalyst or catalysts you used. Hmmm. Well, I guess its the thought that counts. Sorry to be such a party-pooper, but you haven't actually told us anything. I don't mean to sound harsh, but I feel you have the potential to do some amazing practical research. This still could be handy, provided you were kind enough to supply more complete details.

Patiently awaiting useable details,

-the good reverend drone

Moderator   posted 08-01-99 09:45 PM          
Actually, what I am thinking, is that if we work on it, we can have a cheap, high yielding, practical Wacker. What about using another metal besides Pd? I know that Pd is the perfect catalyst for this, but what about a mixed catalyst? Cu with something else?

How about this. Olefin and catalyst in a cheap organic solvent, H2O2 as Oxygen source, and a PTC to cover the aqueous -> organic phase transfer.

Even if this does not have the best yield, have you seen PdCl2 prices these days? We can use allot of catalyst (cheap) and run it for a long time. A traditional Wacker, with PdCl2, CuCl2, and O2, cost a fair amount to run. Especially in large amounts. A 20L reaction (~1000g olefin) would cost well over $1000.

Hopefully, we can work out a procedure that will be as cheap as making coffee.

Member   posted 08-01-99 10:38 PM          
Droney ol boy,Methyl MAn
I've told you everything...
If your having trouble solvating your batch with the corresponding new solvent at the SAME qauntity as DMF, Isolate each component and solvate that seperatly, once everything is solvated
then proceed as normal, Don't look too much into solvents, as long as everything dissolves, keep tabs on the required amounts of DMF that would have been used, keeping your new solvent, around that mark in quantity, Obviously if you use 30L of IPA for 100ml safrole, it will take longer, and require, more than likely a much needed huski cap to be truly fucked(husky hat=one of the hats with the flaps that go over the ears, with the fur).
I'll be back

Methyl man- No, use either solvents, not both together, although, it really woudn't matter

Member   posted 08-01-99 11:01 PM          
I'm sorry about the flavour of my last post,,.I'm just in a hurry today,.
Just do the benzo, how strike wrote it,
Just replace the DMF purely with 100% IPA, Xylene, in molar respects.
You will be happy,.
If you have some other solvent, say meoh, impress yourself and disslove it in that,
Small increments in time and heat will dissolve it,.

If your really lazy, use meoh as the DMF replacement,Don't even try to dissolve anything and shake the bastard for 4-5 hours, while you watch Dawson;s creek,.
It really all boils down to technique vs yield, have some fun

Member   posted 08-02-99 04:23 AM          
Processing 1000g of olefin with the O2/MeOH wacker uses about 10g of PdCl2, 4-5L MeoH, ~40-50g CuCl2, plus some oxygen. Unless you buy the PdCl2 and the other chems from Aldrich, the whole reaction will most likely cost you somewhere around 200-250$ for the chemicals, not 1000$.
Moderator   posted 08-02-99 06:16 AM          
Sorry bout that, my off the cuff calculations were a little off. It should be 4000g of olefin, in 20L solvent.

Methyl Man
Member   posted 08-02-99 10:19 AM          
Hellman: thanks for clarifying that, you know what a neurotic I am for getting things clear before I jump in. This is nice because to know because I would rather not buy DMF also, plus I can get 100% IPA for like $6/gallon. Yeeha.
thanks again

Member   posted 08-02-99 01:05 PM          
So if I understand correctlly one would only use 100% IPA. Not IPA _and_ xylene. So its a single solvent matrix not a mixed one.

Methyl Man
Member   posted 08-02-99 04:24 PM          
Yes, 100% IPA as in anhydrous IPA (not 100% IPA as in not mixed with xylene). He's saying figure out the molar equivalent amount of either IPA or xylene as compared to the DMF amount, and use one or the other. Both are really cheap and OTC for me (thank Buddha).
Now if someone would only post the relative molar amounts (yeah that's right this punk Methyl hasn't learned to compute that yet). DMF is a helluva solvent, melts the ink on labels instantly, so I'm guessin' that the IPA amount would be about 130% of the DMF amount.

Member   posted 08-02-99 05:11 PM          
Osmium: Approximately how much oxygen is requried in the aforementioned procedure?
rev drone
Member   posted 08-02-99 07:46 PM          
There are plenty of metal catalysts for epoxidizng olefins, but only one PRACTICAL one that'll consistantly give you the alpha-methyl-ketone. If you're willing to settle for that, then the worlds your oyster.

I've wondered, if you sued something like a cobalt, titanium, or nickel complex to catalyze the odixation to the epoxide, and coupled it with LiBr or equiv. catalyst to isomerize, would this work? There may be some contentions of competing sulubilities between the catalysts, but it looks kinda interesting.


Glad to see you didn't take me the wrong way. Solubility can be helped by 1: crushing things exta-fine, 2) sonication. What was your yield? Keep fightin' the good fight!

-the good reverend drone

Member   posted 08-03-99 12:02 PM          
If I remember correctly, every mole of alkene needs half a mole of O2. 4000g alkene are roughly 25 moles, so about 13 moles of O2 (~400g), plus some loss because of pressure release etc. That's all estimated, don't take the amounts too literally. Even a small welding O2 cylinder will go a long way for sub-industrial bees.
Methyl Man
Member   posted 08-04-99 01:16 PM          
Anyone wanna toss Methyl a bone and outline the math it takes to figure out the molar equivalents of IPA and xylene relative to DMF? I mean I know that the math will be handy for figuring out molar stuff on every substance, and I know Methyl will have to check MSDSs or other sources to get the molecular weights of things, but an overview of how to do it would be helpful.
Math is not Methyl's strong point (somewhat of a handicap for an aspiring khemist), but he perseveres anyway. Calculators rule!

Thanks beez

Felonious Monk
Member   posted 08-04-99 02:07 PM          
Let me (an untutored miscreant) take a stab at this. Real chemists will pounce on me if I screw up, I know, but onward just the same...

You could just use this tool: 

to see out that the weights for 1 mole of each are:

IPA = (C3H8O) = 60.096 grams
Xylene = (C24H30) = 318.50 grams
DMF = (C3H7NO) = 73.094 grams

Or, you could refer to a Periodic table like this one: 

to see how those numbers are actually derived, using the atomic weights of the individual elements comprising each compound. For example:

if IPA = C3H8O (meaning 3 carbon, 8 hydrogen, and 1 oxygen atom)

then you would refer to the periodic table to come up with the following equation:

1 mole of IPA = (3 x 12.0107) + (8 x 1.00794) + (1 x 15.9994) grams, or...

1 mole of IPA = (36.0321) + (8.06352) + (15.9994) grams, or...

1 mole of IPA = 60.09502 grams

(looks like Iím off by a thousandth gram for some reason, but you get the idea, right?)

Oh yeah, almost forgot, a "mole" is just a fancy name for a gazillion (6 x 10^23?) molecules of a given substance. Some egghead named Avogadro came up with this concept a long, long time ago. 1 mole of every element has the same number of molecules in it (a useful concept, for lots of reasons), but weighs a different amount, due to the differences in the total atomic weights of the atoms comprising it.

Hope that helps, but I better stop now, before I reveal how little I REALLY know about chemistry...

Methyl Man
Member   posted 08-04-99 10:02 PM          
FM: Thank you sir. Now, the way my flawed monkey-mind works, I look at the difference between (rounding off) one mole-weights:
IPA: 61g
DMF: 74g
Difference: 13g (~18%)

It would thus take 18% more IPA to equal the mole-weight of a given amount of DMF. The scale of benzo wacker that the guy in the bar said he favors calls for 388mL of DMF, if memory serves (and it often doesn't), so that would mean I'd want to use about 458mL of IPA to do the same job.

Am I way off base here?

- M.M.

Member   posted 08-04-99 10:44 PM          
Methyl man,
Your close, damn close.
I can't work the math out for you today, but if you can't work it out by next week, I post my secret wepon,.
I'm not at home you see.

To go by what the man in the bar said, you'll need to know how much 388ml of DMF weighs, or even better how much 1ml of dmf weighs,unfortunately it was written on a volume basis, not a weight basis.
For that matter i haven't even got a calculator here, so...

For example if say 1ml weighed 1g(Hypothetical)
1 mole of dmf would be 74mls(or 74*(weight of 1 ml)
then divide 388 by 74(or whatever you calculated the volume of 1 mole of DMF)

which is around 5 mole of dmf roughly in 388mls of dmf,.
Then all you do is measure out 5 mole of IPA
which is around ~304grams

Don't forget this is all based on the fact that 1ml of dmf weighs 1 gram, which i am sure it doesn't. goooooood luck.

I help you if your still stuck, later dude.


Member   posted 08-05-99 03:28 AM          
Since these are only solvents, the molar amounts are not important. No need to start calculating molars for solvents! Use the same amount of each. If the procedure says 388ml, substitute it with 388ml of the other solvent. Or use round figures. That's the way I always do it. Substitute with 400ml.
Member   posted 08-05-99 11:30 PM          
Osmium is right...these are solvents and by their very nature they're just there to allow the molecules of the other substances to flow around and touch each other.
MeOH, EtOH, IPA will all work just fine. The reason DMF was quoted is because various papers use DMF <I>because it used to be an extremely popular organic solvent in the lab!</I> Real labs back in the old days wouldn't have had the supply problems that bees hypothetically have.


Methyl Man
Member   posted 08-06-99 01:22 AM          
Well alright then!  That's what I wanted to hear. IPA it is then for my imaginary friend. He thinks it smells better than that stanky DMF anyway.
Anyone else like the smell of the benzo wacker after the stir? Kinda spicy fragrance, is it not? Aromatically complex (although I don't think it warrants making a men's cologne from it or anything).

Member   posted 08-06-99 01:46 PM          
Try acetonitrile, too. Not quite otc either, but probably cheaper. At least for me.
Member   posted 08-08-99 10:11 PM          
Methyl man,
It's not critical to molarize the solvent system, But that doesn't mean to say it's not the right thing to do,
For me, I like to have those interactions happening at roughly the same rate and energy as strikey bar post.
Just don't forget too much solvent takes longer, to little takes shorter,
How much variance, how fast's your stirrer, what shapoe your pot,( Just kidding, have fun, you can't fail with this baby..>!)
Well that's why it doesn't hurt to use molar quant.

But as we are all a little rough on the edges, and this is clandestine chem,.

Fuck it and have a good time,
Tell me your results when you're through,



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