Mountain_Girl
(Hive Bee)
09-20-02 11:57
No 358472
      P2P from phenyl sodium & ethyl acetate
(Rated as: excellent)
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Another of the 'wanted references':
Tsuruta, Bull. Inst. Chem. Research, Kyoto Univ., vol. 31, 190-200 (1953) (in English); Chemical Abstracts vol 49, 6183b

It seems that there was a chem abstract mistranslation. The synth actually uses chlorobenzene not benzyl chloride.
The paper is entitled 'Michael and some related reactions' and is about 10 pages long. It's not practical to scan and post so I will just give the most important experimental section:


ii. Ethyl acetate and benzyl sodium as reactants.
Benzyl sodium was prepared according to Gilman's method*. Phenyl sodium prepared from 34 g (0.3 mol) of chlorobenzene and 13.8 g (0.6 atom) of sodium sand in 150 ml of dry toluene was refluxed on an oil bath for 3 hrs until the black colour of the precipitates turned to brownish black through reddish brown.
The mixture was cooled to -4C and was added 26.5 g (0.3 mol) of ethyl acetate in toluene in the course of 5 minutes under vigorous stirring. After 2 hrs stirring at about 0C, the mixture was allowed to stand overnight at room temp. and was added some methanol to dissolve the unreacted sodium present, acidified with aqueous acetic acid and the aqueous layer shaken with toluene. The toluene residue was fractionated at 17 mm.

            b.p.(17 mm) 130 - 155 C    7 g  (VIII)
            b.p.(17 mm) 195 - 200 C    7 g  (IX)

An oil (VIII) readily crystallized by ice-cooling and reacted with semicarbazide to give crystals which melted at 187-188C (recrystallized from alcohol-benzene mixture).
Mixed melting point measurement with an authentic phenyl acetone semicarbazone assured (VIII) was phenyl acetone. The viscous oil (IX) was not distinctly identified, but it is very likely that (IX) is methyl dibenzyl carbinol.

* H. Gilman, H. A. Pacevitz & O. Baine : J. Am. Chem. Soc, 62, 1514(1940)




Mountain Boy
 
 
 
 
    Osmium
(Stoni's sexual toy)
09-20-02 12:28
No 358475
      > An oil (VIII) readily crystallized by ...  Bookmark   

> An oil (VIII) readily crystallized by ice-cooling

Does P2P solidify above 0C???

I'm not fat just horizontally disproportionate.
 
 
 
 
    Mountain_Girl
(Hive Bee)
09-20-02 12:46
No 358478
      ?  Bookmark   

Yes I also thought that was odd.
Merck says that the mp is -15 to -16C.

Mountain Boy
 
 
 
 
    Elementary
(Hive Addict)
09-22-02 02:41
No 358921
      Ice  Bookmark   

Depends on how cold the ice was, maybe salt or acetone was added to the ice to lower the temp.

I've got nothing to do today but smile !