Methanol → Methyl phenylglyoxalate

Participants

Reaction Steps

A mixture of 393 g (3 mol) of benzoyl cyanide, 20.3 g (0.26 mol) of acetyl chloride and 202 g of benzoic acid methyl ester was added dropwise, at 22° C., to 450 g (4.6 mol) of concentrated sulphuric acid. The mixture was subsequently stirred for one hour and 72 g (4 mol) of water were then added at 22° C. in the course of about 20 minutes. The mixture was then stirred for a further 3 hours at 22° C. 304 g (9.5 mols) of methanol were added to the reaction mixture and the mixture was stirred for 3 hours at about 70° C. After cooling, the reaction mixture was diluted with 390 g of water. The organic phase was separated off and washed successively with 160 g of water, 160 g of sodium bicarbonate solution and 160 g of water. The combined aqueous phases were extracted twice with 30 ml of toluene each time. The organic phases were combined, and concentrated by distilling off the solvent. Distillation of the residue gave 473 g (96% of theory) of phenylglyoxylic acid methyl ester, which had a boiling point of 136° C./12 mm Hg and a purity of 99% (determined by gas chromatography).

Provenance & Evidence