Author Topic: mdp2p from oxone  (Read 15053 times)

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pickler

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mdp2p from oxone
« on: January 04, 2002, 10:23:00 PM »
I'm about to attempt this synth from rhodium's page(chromics method-oxidation of isosafrole to mdp2p using oxone) and a had a few questions about it. is this synth explosive at all? also in the addendumn by psycokitty, there seems to be some suggestions for some changes in the procedure. now if i follow the synths directions like they were originally written, will i yeild md2p(assuming i'm using isosafrole)?Is it really that easy to make mdp2p that way? i have used brightstar's synth before, but this seems much easier.

Rhodium

  • Guest
Re: mdp2p from oxone
« Reply #1 on: January 05, 2002, 01:02:00 AM »
The synthesis is not explosive as long as water/methanol is present. Dry oxone may react violently when heated. Chromic's writeup will work as it is written, but Psychokitty had some ideas on how to improve it to make it even better - how much better is an exercise left to the reader.

pickler

  • Guest
Re: mdp2p from oxone
« Reply #2 on: January 05, 2002, 02:35:00 AM »
thank you Rhodium. your always there to lend a helping hand to the less experienced bee. ;D  ;D  ;D  ;D

amalgum

  • Guest
Re: mdp2p from oxone
« Reply #3 on: January 05, 2002, 05:39:00 AM »
Yeah I like the epoxide routes, esp the oxone route.  So easy and OTC.  My problem isn't with the epoxidation though, it's with the hydrolization.  There has got to be a better way than the H2SO4 route.  I mean only a 50% yeild?  I would be synthesizing the epoxide all day with oxone if the hydrolization didn't suck hairy balls. Is there a better way?

Oh and by the way, does anybody have the MW of the epoxide?

terbium

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Re: mdp2p from oxone
« Reply #4 on: January 05, 2002, 06:58:00 AM »
does anybody have the MW of the epoxide?
= MW of safrole + 16

amalgum

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Re: mdp2p from oxone
« Reply #5 on: January 05, 2002, 09:49:00 PM »
Thanks

Chromic

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Re: mdp2p from oxone
« Reply #6 on: January 06, 2002, 03:48:00 AM »
I think these values are about right:
Species       isosafrole  anethole  asarone
1mol alkene   162.0g      148.0g    208.0g
1mol epoxide  178.0g      164.0g    224.0g
1mol ketone   178.0g      164.0g    224.0g
1mol A.HCl    215.2g      201.2g    261.2g
1mol MA.HCl   229.2g      215.2g    275.2g



psychokitty

  • Guest
Re: mdp2p from oxone
« Reply #7 on: January 07, 2002, 04:13:00 AM »
If you are going to attempt the Oxone synthesis the way Chromic recommends, then the only two variations that I would suggest are as follows:

Do one or the other NOT both.

1.)  After the epoxidation reaction is over, add undiluted muriatic (pool) acid (31-32% concentration) to the solution so that you can skip the solid filtration step and go directly to extracting the goods.  (The HCl allows the solid to dissolve into the solution).  Oh, yes: 125 mL of acid solution for every 25 g of starting alkene (this ratio is for epoxidation; for glycolization, one can use less).

OR

2.)When the epoxidation reaction is completed, vac distill the methanol or ethanol (both work just fine. You should be left with a biphsic aqueous solution of your epoxide which will therefore be quite easy to extract.  I suspect that the precipitation of solids at the start of the reaction is caused by the addition of the methanol.  Following this logic, all solids should redissolve once the methanol is gone.  This is also a good way of recycling one's methanol.

As for the explosion factor, going the epoxidation route, I don't think it even exists. Here are my reasons: 

By the end of the epoxidation reaction, ALL of the oxone--that is according to the 1991 ref--is used up.  That means that all that is left in solution is your epoxide, water, potassium bisulfate, mabe some sodium bicarbonate, and your alcohol.  I can see no reason why distilling off the alcohol, even at atmospheric pressure, would cause any danger. 

Let's say, however, for the sake of arguement, that there is still some oxone left in solution.  SO WHAT.  The alcohol is still in excess over the oxone and once you start distilling, it is going to react with it to form either acetaldehyde or acetic acid which will both be carried over with the alcohol (or it will stay in the distilling flask dissolved in the water).

For those that are concerned about the notion of heating aqueous oxone solutions with organic substances and the rumored explosive danger in doing so, refer to the original oxone JOC article wherein the authors synthesize MANY organic compounds by reacting oxone with various substances under much more rigorous conditions than those used in the oxone epoxidation synthesis. 

Rhodium, that article is a real treasure!  In it are experimental details to synthesizing ethyl acetate and other goodies from oxone and various other OTC items.

Anyway, if anyone has questions, feel free to ask.

pickler

  • Guest
Re: mdp2p from oxone
« Reply #8 on: January 07, 2002, 06:18:00 AM »
thank you very much Psychokitty. It was a lot easier for to understand what you were talking about( being as i'm not to knowledgeable about chemistry terms).thanks again for clearing everything up for me.

noj

  • Guest
Re: mdp2p from oxone
« Reply #9 on: January 08, 2002, 10:43:00 PM »
Ok, I need some help understanding the terms, or some clarification as to what they mean. Assuming one were using isosafrole and potassium monopersulphate complex, what are meant by 1-alkene, 2-alkene, diol, epoxide, and glycol?

I have my assumptions, but want to make certain.

No One's Jurisdiction

Rhodium

  • Guest
Re: mdp2p from oxone
« Reply #10 on: January 09, 2002, 12:45:00 AM »
For simplicitys sake, I will just draw some phenylpropane derivatives to illustrate the point.

A 2-alkene has its double bond between carbon no 2 and 3 on an alkyl chain, while a 1-alkene has it on the first carbon (between carbon 1 and 2).
An epoxide is a compound which has a three-membered ring somewhere, where two of the atoms are carbons and one is an oxygen.
Finally, a glycol is a compound where two OH groups are situated on carbon atoms next to each other. Is it all clear now?




noj

  • Guest
Re: mdp2p from oxone
« Reply #11 on: January 09, 2002, 02:51:00 AM »
So in this example, the safrole is the 1-alkene, isosafrole is the 2-alkene. After the reaction with oxone, the extractant is known as an epoxide and a glycol. Hydrolysis is refluxing in H2SO4 to form the ketone, MDP-2-P, from the epoxide. Correct?

Psychokitty mentions that following hydrolysis there were 3 fractions: epoxide, the desired ketone, and the diol, in the order of distillation temperatures. This was what I also experienced and didn't catch the fractions seperately due to my lack of understanding. It is also mentioned that it will require a longer duration of hydrolysis than the stated 2 hrs.

Would the hydrolysis occur at ambient temperatures at say 8 hrs, or is the heat (reflux) necessary? Would too long a duration (8 hrs) degrade or harm the ketone?

What is the diol?

Forgive my ignorance. I am kicking myself in the ass for not taking any chemistry courses.

No One's Jurisdiction

terbium

  • Guest
Re: mdp2p from oxone
« Reply #12 on: January 09, 2002, 05:19:00 AM »
Probably better here to use the term rearrangement than the term hydrolysis.


Here is another oxone epoxidation ref. This one uses just water sans any cosolvent.

http://www.nccp.org.tw/pdf/con199614.pdf



Chromic

  • Guest
Re: mdp2p from oxone
« Reply #13 on: January 09, 2002, 06:20:00 AM »
Well, 1-alkene (safrole) to 2-alkene (isosafrole) by heat and KOH. Then we go onto the oxidation with oxone:

If it's buffered (ph near 7): the 2-alkene becomes the epoxide
If it's unbuffered: the 2-alkene becomes the glycol

Then when that's extracted and put into the H2SO4 mixture, if it's the epoxide, then it's hydrolysized to the glycol (addition of water, which opens that little epoxide ring). Then the glycol is dehydrated and rearranged by H2SO4 to the ketone by H2SO4. 2hrs of reflux (with stirring) seems to be enough time, yields have always been pretty good.

noj

  • Guest
Re: mdp2p from oxone
« Reply #14 on: January 09, 2002, 06:56:00 AM »
1.)  After the epoxidation reaction is over, add undiluted muriatic (pool) acid (31-32% concentration) to the solution so that you can skip the solid filtration step and go directly to extracting the goods.  (The HCl allows the solid to dissolve into the solution).  Oh, yes: 125 mL of acid solution for every 25 g of starting alkene (this ratio is for epoxidation; for glycolization, one can use less).


Doing this worked in getting the solids back into solution, but... it created a messy interphase of bubbles which would not totally disappear after an hour at rest. Will try distilling the methanol out next time.

edit: Actually, IPA was used instead of methanol.

No One's Jurisdiction

Rhodium

  • Guest
Re: mdp2p from oxone
« Reply #15 on: January 09, 2002, 10:02:00 AM »
Noj: The glycol is the diol.

halfapint

  • Guest
Re: mdp2p from oxone
« Reply #16 on: January 09, 2002, 04:08:00 PM »
Kitchen chem implementations to Terbium's ref on the water/oxone oxidation (without PTC, buffer, cosolvent or catalyst) could bee as simple as excessively fast stirring, which produces splashing in the flask. Or an aquarium bubbler type pump operated on overdrive. Or manual working with a whisk, done with amphetamine enthusiasm. An optimal amount of oxone (to prevent salting out) for each rxn may be determined experimentally, then noted down and communicated to fellow beez. Pool chems rule! It don't get no better than this.

Combined with thermal rearrangement in place of acid mediated rearrangement, which I believe has been demonstrated for both the diol and the epoxide, and we're giant steps closer to the "one-pot" OTC synth which could prove general for propenyl benzenes to 2-propanones. Even the so-touchy asarone. I have in mind boiling out the water, filtering off the salts, returning the washed organic phase to the flask and then just keep on heating until ketone conversion is achieved. If this is then vacuum distilled, it's not really one pot, but still hugely simplified over previous methods.

In fact, hasn't there been some discussion that 1,2-epoxidation of the allylbenzenes may also produce the 2-ketone?? Will the isomerization step also fall by the wayside?

These are exciting times in which to bee!

Sans Marx, sans Jesùs. Daniel Cohn-Bendit

Rhodium

  • Guest
Re: mdp2p from oxone
« Reply #17 on: January 09, 2002, 08:17:00 PM »
1,2-epoxides are much harder to form, but as soon as you have them prepared, they can be rearranged with LiI to the ketone.

noj

  • Guest
Re: mdp2p from oxone
« Reply #18 on: January 09, 2002, 09:01:00 PM »
Ok, the epoxide was extracted with 2x200mL DCM (doing a 3x scale here) and DCM distilled out. Extraction was repeated 3 times, distilling the DCM out and reusing. Each extraction took more and more yellow out of the solution. After 3 times, it seems that there is still more to get, DCM was yellow, but paused because the solution being distilled, the epoxide, was getting noticeably more brown. Is it possible that it is rearranging from the heat alone? The H2SO4 hydrolysis will be done nonetheless just to make certain.

No One's Jurisdiction

After 3 hrs refluxing with H2SO4, extraction was washed 3x with 5% NaOH. Vacuum distillation yielded 24.6g of the yummy smelling ketone. Pretty low yield from 49g of isosafrole. However, since it worked there is only room for improvement.

RollWitMe

  • Guest
Re: mdp2p from oxone
« Reply #19 on: January 10, 2002, 04:33:00 AM »
What's Oxone again? I don't think we're talking about any peracids. How about using an Ozone generator to do the oxidation. fun fun!

I like to cook! . . . but some dudes in blue vests with yellow letters took my kitchen.