Author Topic: Performic + Hydrolysis questions.  (Read 506 times)

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amine

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Performic + Hydrolysis questions.
« on: March 08, 2004, 04:49:00 PM »
Swim recently attempted the performic with good initial results, however everything went crazy post hydrolysis.

Swim has some questions as he will attempt this again in the near future.

1. How long before addition should one prepare the performic solution, and how long should the total addition take?

Swim waited 3 hours before addition of the performic solution and half way thru the performic reached a boil, swim had to open up the additional funnel to let the rest in.

2. The glycol, what color will it be? Swim retreived a intense orange liquid that started to crystallize when swim stored it in the refrigerator (swim didn't have enough time to do both).

3. Is the black H2SO4 ok?

4. Upon addition of H2SO4, should the glycol turn that dark purple the same way safrole or isosafrole does? or is this a sign of an incompleted performic?.

5. Cleaning up the reaction, (this is where swim fucked up, added some Bicarb to neutralize the acid which is turned ruined all chances of proper seperation between polar and non-polar.).  Is 2x 200ml of DCM enough to extract the residual ketone/isosafrole glycol..etc...etc that exists in the acidic aqueous solution?

Also, post hydrolysis what color will the bottom non-polar layer of ketone et all look like. I had a dark blackish layer. (Could be my dirty acid?? in there 2?)

Any help would be appreciated, swim attempted the Oxone reaction with much better results (primarily because swim followed instructions instead of attempting to be a smart ass like this case).

ApprenticeCook

  • Guest
Hey, did you look at?
« Reply #1 on: March 08, 2004, 09:43:00 PM »
Hey, did you look at?

https://www.thevespiary.org/rhodium/Rhodium/chemistry/peracid.html



Check out the link, it's got heaps of info regarding the procedure and work up, swim just uses the “Buffered Performic acid Oxidation” as it says, works perfectly and nice yields too.

-ApprenticeCook

Saddam_Hussein

  • Guest
safrole performic
« Reply #2 on: March 08, 2004, 10:25:00 PM »
Hello,

Greetings from Tikrit, where the life of a Gringo is cheaper than Iraqi oil! As I see, one of our colleagues has problems in fighting the War on Drugs.

How long before addition should one prepare the performic solution, and how long should the total addition take?

Performic acid is an unstable compound and should always be prepared fresh prior to use. As a rule of the thumb, you can combine your formic acid and hydrogen peroxide solution (slowly and with stirring) and allow it to stand 15-30 min. Then it is ready for use. If you wait longer, you can notice the decomposition of performic acid (gas bells). This does not mean your mixture contains no more performic acid though. Your performic acid mixture is an equilibrium state.

The glycol, what color will it be?

If I remember correctly, the colour of pure glycol will be yellow. However, orange is a valid colour for the worked-up reaction mixture  ;) .

Is the black H2SO4 ok? and Upon addition of H2SO4, should the glycol turn that dark purple the same way safrole or isosafrole does? or is this a sign of an incompleted performic?

If you boil the performic reaction mixture product in MeOH/sulfuric acid, you will obtain a black oil. If you boil safrole or isosafrole in MeOH/sulfuric acid, I think you will have polymerisation (anyone to confirm?). One black oil is not the same as the other black oil  ;) . You will have to distill the ketone, but if you increase the temp a bit more, you can recover some unreacted glycol. By measuring the amount of unreacted product, you can see if your reaction was (nearly) finished or not. If you follow the guidelines on Rhodium's page, there shouldn't be too many problems though.