I´ve made quite a few phenylacetones with this method now, and finally I´ve got a nice overall method.
1 mol of your favourite benzaldehyde
1.1 mol methyl or ethyl 2-chloropropionate
1.5 mol sodium methoxide, preferebly as the commercially avalible and dirt cheap 30% soln in MeOH.
Toluene, about 200-250 ml/mol benzaldehyde. Make sure the toluene is dry.
Add the toluene, benzaldehyde and haloester to a rb flask equipped with a mag stirbar, thermometer and a addition funnel. With cooling, add the sodium methoxide solution dropwise at a rate which keeps the reaction temperature between 10 to 15°C. When the addition is over allow the mixture to stir at room temp for one hour.
The toluene solution of the glycidic ester is now poured into 1 mol NaOH, as a 5% aqueous solution, and the mixture heated to 70-75°C for 60 minutes to hydrolyze the glycidic ester. The toluene layer is then separated from the aqueous layer. The sodium salt of the glycidic acid can now be isolated by concentration of the aqueous solution to about one third of the original volume and cooling to 10°C, filtration and washing with cold MeOH affords the salt in a quite pure form.
The phenylacetone is generated by heating the previous alkaline solution of the sodium salt of the glycidic acid to 90°C, and acidifying to pH 5.5 with either acetic acid or hydrochloric acid. A vigourous evolution of carbon dioxide starts immediately upon addition of acid. The slightly acidic solution is kept at 90°C for approximately one hour, or about 10 minutes after the carbon dioxide evolution has ceased. The solution is then cooled to room temperature, the pH raised to 8, and the ketone extracted with ether, DCM or toluene.
Catalytic hydrogenation freak