Toluene → 2-Methylbenzoic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of K2S2O8 (1.35 g), trifluoroacetic acid (5 mL), 0.083 mL of a catalyst solution as prepared in Example 3(a) above, and toluene (5 mL) was stirred under CO (1 atm) at 53° C. (oil bath) for 16 hours. After the reaction was quenched with water, the unreacted toluene was removed with an air flow over the liquid phase. Ether (20 mL) and chlorobenzene (internal standard; 0.15 mL) were added. After vigorously stirring the mixture for 5-10 minutes, the ethereal phase was analyzed by GC-MS. The GC yield of toluic acid was 260 mg (TON=58, assuming that the Rh oxide used to prepare the catalyst contained 5 molecules of water per each Rh2O3 unit). The ether layer was separated, and the aqueous layer was extracted with ether. The combined ether solutions were evaporated to dryness to give solid toluic acid which was purified by vacuum sublimation. The yield of the purified toluic acid (1H NMR: 95% p-isomer) was 222 mg.

Provenance & Evidence