Author Topic: Differnt brands of Oxone  (Read 1572 times)

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Amicus

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Differnt brands of Oxone
« on: May 07, 2002, 12:24:00 AM »

In the Chromic writeup for the oxone synth, Vibrating_Lights says no base in neccasary if one uses store bought oxone, and that chromic was using 100% oxone. That seems a little confusing to me. If oxone is a brand name isnt store bought oxone 100%? Where would one get the Oxone sans base? Then the big question SWIM needs answered...he hasnt found oxone at all but did find "Shock&Swim" it says active in it is potasium persulfate 80% and sodium carbonate 20%

http://www.tabex.com/Shock%20N%20Swim.pdf



With this stuff would SWIM need to use any extra base or would he be fine? That addendum by V_L is confusing the shit out of me.
"Tests have been run and extra base is only needed if you wish to perform thermal rearrangement"
then he says...
 "However, if using the standard H2SO4 rearrangement the 85% Oxone mix can be used as is because the H2SO4 will dehydrate the glycol to the epoxide before it rearranges the epoxide to the ketone"
Im confused is their some difference in the instances of the word "rearrangment" in each quote?

"Not one shred of evidence supports the notion that life is serious"

Chromic

  • Guest
Some answers.
« Reply #1 on: May 07, 2002, 12:40:00 AM »
The original writeup calls for:

100mmol alkene
200mL MeOH
500ml water
24.4g NaHCO3
72.7g Oxone

If you what you have is 80% oxone and 20% sodium carbonate, then: you will want to use 72.7g / 0.80 = 90.9g 80% oxone. Then since you have 18.2g of Na2CO3 in that mix, you actually have an excess of buffering (an equivilant of 28.8g of NaHCO3!). So do not add any sodium bicarbonate. What you will do is this:

100mmol alkene
200mL MeOH
500ml water
90.9g 80% oxone

Good luck with the reaction. Use the 15% H2SO4 hydrolysis (with or without methanol, if you don't use the methanol, make sure to do the rearrangement on a water bath).

pickler

  • Guest
oxone
« Reply #2 on: May 07, 2002, 02:43:00 AM »
Oxone in 100% can be found, but if you find the 80% kind just adjust your ratios like Chromic said. Swim has only seen 85% oxone and lower,but 100% is available according to other bees.

You can rearrange your epoxide two ways. With h2so4 or thermally. With thremal rearrangement, only the epoxide will rearrange to ketone, but in the h2so4 rearrangement, both the glycol and epoxide will be converted to ketone. The glycol is dehydrated to epoxide then to ketone. The thing about the extra base has to do with weather or not you get glycol or epoxide. If the ph drops too low(below 7) then you'll get the glycol. At 7, epoxide. Hope this isn't too confusing. Pm swim if you need further help. :P

We'll soon find out if I'm a chemist or not!

Amicus

  • Guest
thanks
« Reply #3 on: May 07, 2002, 09:30:00 AM »
Thanks Guys, that answers everything that i need to know. But i do wonder why... if the oxidation is done under neutral conditions you get only the epoxide, under acidic conditions you will some glycol, but under even more acidic conditions the glycol forms the epoxide (before it goes to ketone). Seems like the Ph should corelate to the type of product without skipping some Ph values and then kicking back in. Catch my drift?
gycol to ketone mechanism???
H+ to the benzylic OH
H20 leaves giving carbocation
H on the C of the remaining oh group leaves and gives it's e- to carbocation making a double bond. the enol tautamerizes to make ketone. Is that right?
What about the glycol formation from the epoxide?
Sn2 "like" addition of h20 after an H+ hits the O?
it sounds all right but the concept of an acid making both happen with good yeild looks like a mutualy exclusive proposition. Reackon this southern boy need some learn'n

"Not one shred of evidence supports the notion that life is serious"

Chromic

  • Guest
That's because you don't...
« Reply #4 on: May 08, 2002, 10:52:00 PM »
At or above a pH of around 7, the epoxide forms. Below that pH you get the glycol. The H2SO4 hydrolysis does not dehydrate the glycol to the epoxide.  The epoxide isn't the intermediate for the pinacol rearrangement.

What I know is that the mechanism involves protonation of one of the hydroxys to make a good leaving group, loss of water, formation of a carbocation, then rearrangement to the ketone (abstraction of a proton by the carbocation? my memory is shaky on this step, mechanisms have never been my strong point).

Amicus

  • Guest
Damn
« Reply #5 on: May 09, 2002, 12:51:00 AM »

pickler

  • Guest
And Pickler gives you the finger Amicus.
« Reply #6 on: May 09, 2002, 02:54:00 AM »

Amicus

  • Guest
Amicus Apologizes
« Reply #7 on: May 09, 2002, 03:16:00 AM »

I was being playful, not inflamatory. Its hard to tell the difference when this is all typed instead of spoken. I have gotten alot of good info from you and more importantly i enjoy your posts, so dont think i dont respect you.
::Amicus retracts finger and shakes hands::

"Not one shred of evidence supports the notion that life is serious"