Author Topic: 02 Wacker Help Please  (Read 6041 times)

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blaztoff

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02 Wacker Help Please
« on: December 30, 2001, 06:46:00 AM »
Well this is the third time Swim has tried running the DMF 02 wacker. Followed it exactlly as KRZ posted. Took notes to see where I could go wrong. 1st run. Nothing. Attributed it to poor stirring and first time. No real O2 uptake.
2nd run. Nothing a little dissapointed thought I had ketone looked right but on redistiling all it was was safrole and DCM . Collected preety much close to fractions of each with only minimal loss of safrole and DCM. Attributed to stirring once again since O2 uptake was rather minimal till I decided to pick the vessel up and shake it every time I pressurized. Boom major O2 uptake.
3rd run. Nothing. Cant figure out what went wrong. This time 02uptake seamed right on que with the posted uptake even. Only diffence O2 uptake was a little more milder and longer than posted  02 uptake 10,11,11,12,11,10,9,8,6. Stirring seamed ok by ear. Cant see inside vessel. (teflon coated). On each pressurization also shook the vessel for a minute to insure O2 uptake. Always ate up 3 or 4 psi when done.
 Afer nothing. Hit it with 5% HCL solution Two layers Nice greenish one on top and pale orange yellow on bottom. Oh looked like about 40ml of a dark oil that immediatelly vanished into the top layer when poured the mix into sep funnel . On distillation 260ml back of DCM out of 300ml and then basically all safrole. About 284grams out of 324grams started. Changed flask again once noticed a new oily substace falling out into the recieving flask. Total of this 38grams and some tar in distilaation flask.
Tried Bisulfite test Unconclusive. Always had problems with this. Fist mixed about 30 grams BIsulfite into about 20ml H2O shook then poured about 2ml Of mystery. NOthjing exccapt that an yellow oil rose to top. But on fridge come back little later and it was one big white not freezing crystls but powdery crystals  that evaped to 2layers of somrething when left out for a short time period.
What is going wrong. Does this work? My guess here once again would be stirring but 02 uptake lokked right. What are sighns of faided good reaction. Only posts really descibing it I found really on this were mainly from Frost and we all know what a bullshitter he is. Is the ketone if done form a dark red oil on bottom like he said?I know On the benzo the color is from the Hydroquinone. But dont believe anything frost posted. The only color ive gotten on bottom is a light yellowish or greenish tinged. but dosnt look like ketone. Please any advice updates on wacker? Suggestions

Antibody2

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Re: 02 Wacker Help Please
« Reply #1 on: December 30, 2001, 05:41:00 PM »
> But on fridge come back little later and it was one big white not freezing crystls but  powdery crystals

when they separated into two layers, where did the powdery crystals go, up or down? if they went up, you are in the money dude, if they went down, so sorry.

couple pointers on that test, it needs be a saturated bisulfite solution, ei keep adding bisulfite to h2o until no more will dissolve and it starts to settle out on bottom of test tube. I often don't even remove the excess, as when the ketone reacts, the excess will go into solution and maintain  saturation. If there are alot of contaminates in your 'ketone' you will require a small amount of alcohol in your mix, otherwise the contaminates will inhibit crystal formation. say 5mls EtOH for a 20ml saturated solution, MeOH works also. Prerefrigerate you saturated solution, and it needs shaking like hell, often sveral times, a little ketone reacting each time.

As far as directions go, try to follow in LabTops footsteps, he didn't delete half his posts on board like KRZ did, which may indicate a clearer conscience. If you notice that O2 is the shit thread, everyone who FAILED was following a recipe posted by KRZ (only falsly validated by Frost), but you wouldn't know that unless you were around before he deleted it, covering his tracks?

sunlight

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Re: 02 Wacker Help Please
« Reply #2 on: December 31, 2001, 02:08:00 AM »
Is the recipe in Rhodium's page ?

terbium

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Re: 02 Wacker Help Please
« Reply #3 on: December 31, 2001, 06:49:00 AM »
Yes, what Antibody2 says about the bisulfite.

It would be interesting for you to try a control experiment where you measure the oxygen uptake while performing the reaction exactly as before except without any safrole.

blaztoff

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Re: 02 Wacker Help Please
« Reply #4 on: December 31, 2001, 12:03:00 PM »
That was going to be my next Guess. Possible sloww leak maybe escaping from O-ring seal or the pressure release valve. Also had idea of running the O2 line in from the needle valve into the solution itself. Figure the pressure bieng generated from the O2 bieng put into the vessel should be enough to get some pretty good stirring going. That along with magnetic should be cause of good mixing and O2 consumption.
Also was going to try and possibly set it up for a constant 36psi O2/. Have a speacial regulator fitting that dosnt allow blowback or whatever into the regulator and allows you to hook up youre hase and fitting directlly to vessel and run the line into the solution mix. Fitting used for carrier gass intro for distillations. Hell of a lot quicker on your dist.
Also had another idea for the wacker. Seams like the best Wacker or most consistent Wacker is the Benzo/Meoh BUt that wacker makes for a bitch in cleanups and not the best yields. The O2 wackers though are tricky as fuck not really reliable but damn are they clean as fuck and very easy. Good yields. Well I remember  a old reference from the Japanese gurus that stated using pressurization and using I forgot what they are called but something like Benzo to form youre ketone. This would eliminate the need of a co-catalyst like Cupric chloride which I think (dont really know) is responsible for a the aldehyde in the O2 Wacker. Also eliminate the need of special vessel required for Pressure and also make for a mild cleanup: way less Hydroquinone mess to deal with. Your water washes should then take care of that shit and leave rather a simple dist for Ketone. I believe the you would have to judge the amount of O2 uptake bieng eaten by the Reaction via pressurization and the Benzo carring the O2 accros. Just figure out how much moles are bieng used and calculate the ratios for 1m.
I figure a 10% of normal benzo run with a constant pressuzation of 5-7psi should do the trick. Let it run and you dont even really have to worry about the aldehyde forming because no cupric. The benzo just goes to hydro and the O2 bieng finished taken up just will form H20 or whatever. (Not really sure). This could then be done with regular glassware and will make youre Benzo go a lot longer since it seams to be harder to come by. Also less mess you can probally recycle youre palladium. Well just raving on. Will try it after the New Years.
On one note what co-catalyst should use here. Was using CuCl 2H2O wheras Labtop used CuCl. I know less Ions to fuck youre shit. Isnt that the only real diffence from Labtops and KRZ.
One more Heating mantles suck. Just had mine catch fire burn my fingers. Ironically the productstaed safe as it had made it into the recieving flask and only lost the fucking mantle and flask and a stupid claisen head. Whew prayer on that one.

Osmium

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Re: 02 Wacker Help Please
« Reply #5 on: December 31, 2001, 12:56:00 PM »
> Well this is the third time Swim has tried running the
> DMF 02 wacker. Followed it exactlly as KRZ posted. Took
> notes to see where I could go wrong. 1st run. Nothing. [...]
> 2nd run. Nothing [...]
> 3rd run. Nothing. Cant figure out what went wrong.

MAybe it's time to change some of the reaction parameters after the third failure.

> had idea of running the O2 line in from the needle valve
> into the solution itself. Figure the pressure bieng
> generated from the O2 bieng put into the vessel should be
> enough to get some pretty good stirring going.

Yes. For a second or two, until the vessel is pressurized.

> Also was going to try and possibly set it up for a
> constant 36psi O2/.

Fuck constant pressure, I'd rather use twice the pressure instead.

> On one note what co-catalyst should use here. Was using
> CuCl 2H2O wheras Labtop used CuCl. I know less Ions to
> fuck youre shit. Isnt that the only real diffence from
> Labtops and KRZ.

That might be the only difference, but it also happens to be an important difference!

terbium

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Re: 02 Wacker Help Please
« Reply #6 on: January 01, 2002, 03:13:00 AM »
On one note what co-catalyst should use here. Was using CuCl 2H2O wheras Labtop used CuCl.
Really? You are using cuprous chloride dihydrate? I didn't even know that cuprous chloride had a dihydrate. I would have expected that you were using something like cupric chloride dihydrate.

Ritter

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Re: 02 Wacker Help Please
« Reply #7 on: January 03, 2002, 05:26:00 AM »
Someone told me that IPA 02 Wacker has produced the most consistent yields of 2-propanone.  The secret is to warm the reactor to at least 40'C to accelerate O2 absorption to a decent pace.  It has been observed that when this variation is run at room temp, absorption may completely cease long before even half the alkene has reacted-no matter how hard you mix it.  One mole of alkene absorbs over 80% theoretical oxygen in less than 6 hours using an initial pressure of 75psi.  It is very important to use some type of non-metallic  material for the rxn. vessel.  Many people here have wasted thousands of dollars worth the Pd salts over this mistake!

Osmium

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Re: 02 Wacker Help Please
« Reply #8 on: January 03, 2002, 10:01:00 AM »
Ritter, can you get a detailed writeup including yields from that someone?

legionbob

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Re: 02 Wacker Help Please
« Reply #9 on: February 14, 2002, 09:31:00 AM »
SWIB would just like to say he's done just fine with a pop bottle, MeOH, PdCl, CuCl2, a little H2O and alkene.    Pressurize to 40 psi, shake every now and then for the first few hours purging and repressurizing a few times, then shove under your bed at room temp over night.   No unreacted alkene/iso to speak of, maybe a drop or three.  It sounds too primative to work, yet it does!   (About 65% molar yield, probably substantially higher with a decent high-vac distillation rig or chromatography.)    I'm not sure why people keep screwing this one up...only trouble SWIB had was in the start when he tried to guage reaction progress by time or color changes...now just leaves it overnight to take care of itself (about 18 hours total or so.)



Legion Bob
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