Author Topic: P2P-Success! (Phenylacetic acid/AA/NaAc)  (Read 1783 times)

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Xicori

  • Guest
P2P-Success! (Phenylacetic acid/AA/NaAc)
« on: November 25, 2003, 03:53:00 PM »
High Bees!

Last night swim met an old, weird looking man in one of his dreams... the man told me the following:

Into a 2000ml RBF were added 288g of Sodium Acetate, 57,7g of phenylacetic acid and 350g of Acetic Anhydride (all reagents were p.a.).

A reflux condensor and a trying tube were added to the apparatus, and the mixture was refluxed for 20 hours.

Note: At first a heating mantle was used, but this didnt work. The solution was unstirrable because of the enormous masses of NaAc.- so the solution overheated! -> A oil bath at 160°C provided good heating. A lot of the NaAc was just sitting at the walls of the flask.

After 20H about 200ml of Acetic Acid/Acetic Anhydride were distilled of (760mm Hg), and after cooling of the residue 600ml of water were added and the mixture was stirred vigurously. (a lot of heat was generated here, because of the exothermic reaction of the excess anhydride with water.)

After the solution had cooled down (all solids went into solution) 2 layers formed. the top layer was dark red/brown while the bottom (aqueous) layer was only slightly orange.

The whole stuff was extracted with 3x 100ml of DCM. The combined extracts were washed with 5% NaOH-Solution, until the washing solution stayed alkaline (removing excess Acetic Acid and Phenylacetic acid).

The DCM layer was washed once more with water to remove traces of NaOH, dried over sodium sulfate (wash the drying agent with some additional DCM).

The DCM was distilled off and the residue was distilled under vacuum with a 30cm-vigreux column.

At 95°C (14mBar ~10mm Hg) a yellow (maybe a hint of greenish) liquid distilled over. During the distillation the temperature rised to ~120°C (distillate had the same color during the whole distillation progress).

Yeild: 35,4g of P2P (62,3% of theory)

Best wishes,
xicori

PS.: the old man also gave me some photos, so if anybee is interested they could be posted here (if rhodium has some webspace :) )

jackhole

  • Guest
VERY interested in photos!
« Reply #1 on: November 25, 2003, 05:06:00 PM »
I would be very interested in seeing photos of this!  And congratulations on your success!


Osmium

  • Guest
Holy shit, that's a lot of NaOAc you are using
« Reply #2 on: November 25, 2003, 11:15:00 PM »
Holy shit, that's a lot of NaOAc you are using there! Why so much?


Xicori

  • Guest
high osmium... according to ...
« Reply #3 on: November 26, 2003, 04:22:00 AM »
high osmium...

according to

https://www.thevespiary.org/rhodium/Rhodium/chemistry/phenylacetone.html#phenylacetic

the reaction gives the best results when that much catalyst is used (and sodium acetate is very cheap too).

But next time swim will use less catalyst, because the reaction is hard to handle with that much salt in it :P - then a heating mantle can also be used to heat the reaction mixture. (having an oil bath 20H @ 160°C gives the workspace this disgusting McDonalds-smell  ::) )

...but finally it worked, with a very nice yield :)

Xicori

  • Guest
pictures...
« Reply #4 on: December 06, 2003, 10:11:00 AM »
Thanks to Rhodium (he has uploaded the files) now some pictures from the procedure:



Vacuum distillation of the residue after stripping off the DCM. (Vigreux column, aspirator vacuum)


pale yellow P2P in the receiver


Vacuum gauge - 14mbar


~ 35g of clean P2P awaiting future treatment ;)

I´m sorry that i´ve ne pictures of the reaction itself, but it was really nothing spectacular...

Best wishes
xicori

Chewbacca

  • Guest
Congrats!
« Reply #5 on: December 06, 2003, 11:32:00 PM »
Well done on that one Xicori, you must bee pleased! I read over your excellent work with PCP synthesis also, you are the man! Thats lotsa kickarse equipment you have there. Sure beats my cigar tube reactions!  ;D


WizardX

  • Guest
Nice !
« Reply #6 on: December 08, 2003, 02:02:00 AM »
Good work Xicori !

terbium

  • Guest
Phenylacetic acid / Acetic anhydride
« Reply #7 on: December 21, 2003, 12:30:00 PM »
In cleaning out some old papers I stumbled across a rare instance where I had actually written down a working formula.

Here is what the note gives for a procedure I was using for P2P:

1 liter Acetic Anhydride
280 grams Phenylacetic acid, added in 4 portions
275 grams anhydrous Potassium acetate
reflux 12 hours
dilute to 8 liters with water

There was no notation about what sort of yield I was getting.