Water → 2,3,5,6-Tetramethyl-1,4-benzenedicarboxylic acid

Participants

Reaction Conditions

Reaction Steps

2,3,5,6-Tetramethyl-p-xylene-α,α'-diol (5.0 g, 26 mmol) was suspended in 250 mL of distilled acetone, and cooled to 0° C. To a separate solution of chromium (VI) oxide (14.15 g, 0.14 ml) in 50 mL of water was dropwise added concentrated sulfuric acid (14.5 mL, 0.26 mol) at 0° C. during 45 minutes. This mixture was then added dropwise during 30 minutes to the acetone solution, with stirring at 0° C. The mixture was stirred vigorously at 0° C. for 1 hour, then at room temperature for 18 hours. The reaction mixture was concentrated by rotary evaporation, and 1 NHCl was added to attain pH 1. The product was precipitated by cooling, then was filtered, washed with water (3×) and diethyl ether (3×), and dried at high vacuum to afford 4.55 g (80%) of the product (HOOC--C6 (CH3)4 --COOH) as a white solid, m.p. >300° C.

Provenance & Evidence