kurupira (Newbee)
08-16-02 17:35
No 346096
      paa-->p2p using MnCO3  Bookmark   

Could somebee post the experimental details? (and yields specialy the MnCO3 part)

"P-2-P via phenylacetic acid and ThO2 or MnCO3

A.I. Vogel, A Textbook of Practical Organic Chemistry, 1st Edition (Longmans, Green and Co.), 1948, London, pp. 698-700 and 336-338."

I know you bees have this, just copy, paste, and post!wink
(Old P2P Cook)
08-16-02 20:01
No 346123
      Org. Syn.  Bookmark   

Well, I only have a hard copy version of Vogel so I can't copy and paste and at the moment I am too lazy to type but here is a thread that contains a pointer to the Organic Syntheses version of this procedure:
Post 323419 (Rhodium: "tube furnace", Stimulants)

Post 226039 (terbium: "Re: PAA -> P2P using lead acetate", Methods Discourse)
08-17-02 07:19
No 346216
      Thanks Terb but i am more interested in the MnCO ...  Bookmark   

Thanks Terb but i am more interested in the MnCO3 part (less toxic).
you're too lazy to type, ok... at least we can discuss if worth to try this rxn (yields... etc). 
(Master Searcher)
08-17-02 08:46
No 346235
      Post 18563
(Rated as: excellent)

Post 18563 (Mastermind: "P2P", Methods Discourse)
Patent US2108156
Patent US2612524
Patent US2697729
Patent US2811559
Patent US3075016
Patent US3660491
Patent US4172097
Patent US4754074
Patent US5750795

The hardest thing to explain is the obvious
(Stoni's sexual toy)
08-17-02 11:37
No 346263
      If you have access to acetic anhydride I strongly ...  Bookmark   

If you have access to acetic anhydride I strongly suggest the PAA/NaOAc/Ac2O route.

I'm not fat just horizontally disproportionate.
(Old P2P Cook)
08-17-02 22:04
No 346351
      Manganous oxide catalyst.  Bookmark   

Here is what Vogel (3rd Ed.) says about using manganous oxide for the production of methyl benzyl ketone from PAA and GAA:

IV,140   Methyl Benzyl Ketone
Use the apparatus as described in Section III,72 and adjust the furnace to a temperature of 400-450
(centigrade). Although a manganous oxide catalyst gives satisfactory results, thoria is more convenient in practice.

The procedure then goes on to describe the preparation of the thoria catalyst and preparation of the P2P in about 50% yield based on the PAA.

Preparation of the manganous oxide catalyst is described in section III,72 for the preparation of dialkyl ketones from acids in the tube furnace.

Here is what Section [b]III,72 says about preparation of the catalyst:

Fill a Pyrex tube, 100 cm long and 1.5 cm internal diameter, with pumice (4-8 mesh). Transfer the pumice into a thick suspension of about 40 grams of freshly precipitated manganous carbonate in a beaker. (The managanous carbonate is prepared by adding a solution of 38 g. A.R. anhydrous sodium carbonate to a solution of 70 g. of A.R. crystallised manganous chloride, and filtering). Heat the beaker on a hot plate with vigorous stirring with a glass rod until most of the water is expelled, then transfer the solid to a shallow porcelain basin and continue the heating, with stirring, until the lumps no longer cling together; take great care to avoid local overheating. It is important to adjust the volume of water used in preparing the suspension of manganous carbonate so that most of the latter is absorbed by the pumice; if much water has to be evaporated, the manganous carbonate does not adhere satisfactorily.
08-19-02 15:24
No 346864
      I see... the apparatus is almost the same as the ...  Bookmark   

I see...
the apparatus is almost the same as the ThO2 method (i mean too expensive to swim) and I think it needs a N2 line to getup yields.
Os: aa is accessible to SWIM (not me) and its more attractive too (easy to perform)