Lithium Hydroxide → Phenylacetic Acid

Participants

Reaction Conditions

Reaction Steps

A 20 mL aliquot of 0.15 mmoles/mL of potassium tricarbonyl [triphenylphosphine] cobaltate was charged to a 100 mL three-neck round bottom flask under nitrogen and cooled to 5° C. Phenylacetyl chloride (0.4 mL; 3.0 mmoles) was added to the flask. The solution containing the preformed cobaltate complex was then charged into a 300 mL autoclave by means of a transfer needle under nitrogen. The autoclave had previously been charged with 12 mmoles (0.287 g) of lithium hydroxide as a suspension in 22.5 mLs tetrahydrofuran and 5 mLs water. The vessel was sealed, flushed with carbon monoxide, pressurized to 900 psig and heated to 90° C. for nine hours. The autoclave was vented and the contents were poured into a 250 mL separatory funnel. The reaction mixture was acidified with 10% hydrochloric acid and then treated with an excess of iodine. The organic phase was diluted with 100 mLs of diethyl ether and the lower aqueous phase was discarded. The organic phase was washed with saturated sodium thiosulfate until the color of iodine was dispelled. The resultant light yellow diethyl ether phase was washed with 10% sodium hydroxide (3×25 mLs) and the organic phase discarded. Acidification of the combined aqueous sodium hydroxide solution followed by re-extraction with diethyl ether (2×75 mLs) gave a clear solution. The solution was dried over MgSO4 and evaporated to give 0.02 mmoles (0.76% yield) of phenylpyruvic acid and 2.18 mmoles (72.6% yield) of phenylacetic acid as identified by mass spectroscopy and comparison to an authentic sample.

Provenance & Evidence