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Author Topic: Epoxidation using Performic. Buffered or Unbuffered?  (Read 917 times)

thescientist3000

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Epoxidation using Performic. Buffered or Unbuffered?
« on: November 18, 2011, 05:27:17 AM »
What has the concensus been on this subject?

Buffered or unbuffered?

Notes would like to be shared, if a simple aknowledgement is shown, sharing will begin.  ;)

Vesp

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #1 on: November 18, 2011, 05:36:00 AM »
http://127.0.0.1/talk/index.php/topic,369.0.html

Please edit your above post to be within the rules and guidelines of this site. Thank you. :)
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thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #2 on: November 22, 2011, 09:27:33 PM »
What substitutes can be used in place of the solvent DCM?

Acetone can be used for the epoxidation, but then there is a worry of the acetone turning into a explosive... Can someone share more on this please.

As for the extractions, and back extractions, can acetone be used for this? 

What is the best replacement?

Thanks.
« Last Edit: May 07, 2012, 03:26:01 AM by thescientist3000 »

fractal

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #3 on: November 22, 2011, 10:01:54 PM »
There is a long list of threads to answer your question, bumping won't help. Just READ and you'll understand whats going on. All there is to it. If you lack this basic skill take up a different hobby.... The post from vesp tells you that this post doesn't fit because the information is already available, do not help your self to a ban.

lugh

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #4 on: November 22, 2011, 10:04:57 PM »
You were given a link to the thread titled Detailed Methodes in:

http://127.0.0.1/talk/index.php/topic,2698.msg27286.html#msg27286

which will answer all of your questions as far as peracid oxidation ;) As far as alternatives to DCM, if you study that thread you'll realize it's far superior to any other solvent for this particular reaction so you should continue researching your questions on the internet until you find out how to get it from available sources :-X   Please study what's been posted instead of expecting anyone to spoon feed you  8)
« Last Edit: November 23, 2011, 01:09:52 AM by lugh »
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thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #5 on: November 23, 2011, 02:31:00 AM »
Hi Guys.

Access to that link a couple days ago, only to realize I have read over that exact information elsewhere before.

So to say go read may be a bit premature. 

DCM is becoming a challenge, only reason I asked.  Distill from stripper, blah blah, its superior solvent, acetone with form a nitrile with excessive h2o2 that is left over, or DCE can also be used.. OK GOT IT.

Ooooh.
« Last Edit: May 07, 2012, 03:26:36 AM by thescientist3000 »

Sedit

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #6 on: November 23, 2011, 04:59:48 AM »
DCM is the lest challenging solvent to get and recycle IMO whats the problem with obtaining it other then laziness?
There once were some bees and you took all there stuff!
You pissed off the wasp now enough is enough!!!

lugh

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #7 on: November 23, 2011, 03:16:02 PM »
Detailed Methodes was originally posted on the Hive by LaBTop, so it's not surprising that you've seen it before since it was reposted on Synthetikal after the demise of the Hive and has been made available on the internet in many places since then :P The title of this thread supports the hypothesis that you haven't really understood that thread yet  ::)  Please start reading and understanding what's been posted instead of expecting to be spoon fed information  8)
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poorfish

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #8 on: November 23, 2011, 04:09:44 PM »
Quote from: thescientist3000 on November 23, 2011, 02:31:00 AM
I got access to that link a couple days ago, only to realize I have read over that exact information elsewhere before.

So to say go read may be a bit premature. 

DCM is becoming a challenge, only reason I asked.  Distill from stripper, blah blah, its superior solvent, acetone with form a nitrile with excessive h2o2 that is left over, or DCE can also be used.. OK GOT IT.

Ooooh.

Novel idea - since you've cleeeaarly read that post in great detail before now, AND you've found your replacement for the "impoooossible to find anywhere" DCM ::)

Why don't you try BOTH and report back to us with a comparison of the relative yields??  :o

Experiment is king, Mr. Scientist.

OR you could re-read the damn post; WHEREIN IT SAYS WHICH IS BETTER.

...but that would be silly, everyone knows you only need to read experimental notes one time to fully understand the reaction in question ::)

...are you by chance familiar with a little web archive by the name of Rhodium, Mr. Scientist?
And the boy's father was shouting:

Quote
"He doin' the stanky leg! He doin' the stanky leg! Two yearz ol' an' he doin' the stanky leg an' he NOT EVEN TRIPPIN'!!"

The infant was, in fact, doing 'the stanky leg.'

Believe me boy, I seen everything.

NeilPatrickHarris

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #9 on: November 23, 2011, 04:42:45 PM »
here's my .02 on the solvent used for the oxidation of isosafrole, i posted it in an already-existing thread.  if you UTFSE'd the question you should've been able to find it, but anyway here it is:
http://127.0.0.1/talk/index.php/topic,1686.msg24100.html#msg24100

there are plenty of peracid-related posts around here that are already existing, why not dig those up, read them, then reply to any questions you have regarding what you just read within that existing thread rather than making a new one?

on the topic of buffered vs unbuffered, buffered has a reputation to give higher yields just follow chromic's advice from a rhodium mirror.  then for the rearrangement, hcl has a history of giving higher yields over h2so4.  i'm sure there's an existing post somewhere here talking about the hcl rearrangement if u UTFSE

thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #10 on: November 28, 2011, 09:56:51 PM »
Once again, thank Neil, for the informative and to the point post.   You pretty much answered all my concerns.

To the "others" hmmm.  thanks for your feelings?

TS

thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #11 on: December 12, 2011, 04:49:02 AM »
It appears as the the current fuckup occurred while attempting to neutralize the epoxide before distillation.

5% naoh washes were used, which took quite a bit to bring the ph up.  It started as a yellow orange juice, and after adding the %5 naoh solution, the mix suddenly turned dark red, and a bottom WHITE layer.  The layers seemed to reverse, and all of a sudden get extremely dark.  Both are saved, the aqueous washes which are a lighter yellow, apple juice perhaps, and the dcm/oil which have now turned to this strange new mix.
ph is now at 8, like eulesis says in his version. 

If one were to just stop before this point it would have stayed its nice orange juice color, and then the dcm could be distiled off for a nice HCL hydrolysis.

Is it saveable/usable ? Or is it trash?  It now looks like the transmission fluid color, but the bottom layer is white.  Man frustrated.  Time to bust out the Bubba and smoke one@!

TS

thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #12 on: December 12, 2011, 05:46:42 AM »
here ya are

fractal

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #13 on: December 12, 2011, 11:43:48 PM »
Well what you're isolating isn't an epoxide, the ring is protonated and cracked by remaining formic or acetic acid giving isosafrole monoformyl/monoacetyl glycol. Hydroxides will hydrolyze the glycol ester lowering yields of the pinacol rearrangement so neutralization is not the best option here. Too late now I guess, you should still yield something though.

thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #14 on: December 13, 2011, 04:01:32 AM »
Hi Fractal.  Thanks for responding.  Patience is a killer waiting to see what happens with this lol.

Couple questions if you can spell it out a little clearer.
1. If one were to re-do this a second round, would doing a dH2o wash be sufficient, decant aqueous layer, than proceed to pinacol?
2. Is the ph before the pinacol important, as proceeding directly after has a ph of 2 or so. acidic.
3. On this "messed up" batch, which layer does one use on the pinacol?  There is a red layer, and a white/cloudy layer.  When this "naoh wash mis-hap" occured the layers reversed it appeared.  Lower orange layer/upper aqueous layer, is now Lower white,cloudy layer/upper dark red layer.

Swim is scared to do a naoh wash at all again, athough the first wash definitely made the two layers separate a lot more clearer.  It was when more washes were done that the damage was done, around neutral ph this occurred. I dont know why eulesis says to neutralize before proceeding to pinacol...strange.

Thanks again.

Proposed future method:
1. Wash with larger amount of distilled h20.
2. Decant dcm layer.
3. Back extract aqueous layer with dcm.
4. Combine dcm
5. Proceed to pinacol.

Oh is drying of dcm necessary for pinacol?

fractal

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #15 on: December 13, 2011, 05:41:09 AM »
There is no swimming aloud here ;) I would do more than one wash, the cleaner your products are the better and that goes for anything. I always do the pinacol in methanol/water, you need a protic solvent. You use 15% H2SO4 so water doesn't hurt at all and removing would do nothing considering you are adding more after you distill the DCM off. If you want to know what the PH should be do the math, in any gen chem book. You want the DCM layer, mix a small amount with water to make sure you have the right one. You can figure this type of stuff out though. That batch is not ruined but you will not yield as much as if you had not added NaOH. What's left is always red after you distill off the DCM :P

thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #16 on: December 13, 2011, 08:40:26 AM »
I suppose a lot of questions were for certainty.  A lot of answers were just sitting in storage in the brain.

The plan was to use HCL instead of H2SO4, in same concentration 15%.  Less harsh on the ring and supposedly better yield.  Only read about it though.

A new batch is spinning away, but will revisit the messed up one soonafter.

jon

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #17 on: December 14, 2011, 01:56:51 AM »
rememeber if you wash a diol or monoformyl ester with water, it is partially soluble in water so be sure to back extract the pooled washes.
i never understood why someone would go through 4 steps to get only 50% yeilds though.
i could do the same thing in 2 steps with bromo safrole and get comparable yeilds.
and recycle my unreacted bromo safrole for reuse so yeilds are actually higher if you take that into account.
of course the only way you could do that is if you did'nt heat it and cause the e2 side reaction and that takes 4 days but during that time you do nothing, just let it sit.
iodosafrole gives 90% yeilds overall start to finish but for some reason only one person has been able to duplicate my sucess, because it is a tricky reaction to learn.

thescientist3000

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #18 on: December 15, 2011, 09:36:24 AM »
Had a nice long post which got deleted as the backspace was hit on accident.  Frustrated.

Anyways, a red oil was distilled.  Suspected first 20ml out of 200ml was iso, which tainted the color.  This is suspected, since the distillation head showed a golden/green oil soonafter but distillate flask was never changed. arg!.  29.5" vac 140c first drop came over, majority came over at 150c.

Will this be okay to proceed with?

Cautious to re-distill due to the touchy nature of the oil at this point and decomposition at anywhere above freezer temps.

Further details later on whole proccess. 

If a new thread is required, please inform.

TS

fractal

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Re: Epoxidation using Performic. Buffered or Unbuffered?
« Reply #19 on: December 15, 2011, 10:29:30 PM »
I've never distilled the isosafrole glycol but under vac it's all good. You are fine to continue, hope you separated the isosafrole for later use. No new threads man, the ones you posted weren't even necessary as there are already threads you could have bumped. Not being an asshole just letting you know for next time. New threads are for completely new topics;) Glad to hear it worked out for you=) Just do the pinacol and you're golden.
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