Water → 2,3,5,6-Tetramethyl-1,4-benzenedicarboxylic acid
Reaction equation
[CH3:1][C:2]1[C:7]([CH3:8])=[C:6]([CH2:9][OH:10])[C:5]([CH3:11])=[C:4]([CH3:12])[C:3]=1[CH2:13][OH:14].S(=O)(=O)(O)[OH:16].[OH2:20]>CC(C)=O.[O-2].[Cr+6].[O-2].[O-2]>[CH3:8][C:7]1[C:2]([CH3:1])=[C:3]([C:13]([OH:14])=[O:20])[C:4]([CH3:12])=[C:5]([CH3:11])[C:6]=1[C:9]([OH:16])=[O:10]Participants
Conditions
- Temperature
- 0 °C
Procedure
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 1NHCl 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.
Workup
- stirringThe mixture was stirred vigorously at 0° C. for 1 hour
- concentrationThe reaction mixture was concentrated by rotary evaporation, and 1NHCl
- additionwas added
- customThe product was precipitated
- temperatureby cooling
- filtrationwas filtered
- washwashed with water (3×) and diethyl ether (3×)
- customdried at high vacuum
Sources & evidence
- ORD record
- ord-2f0ee497d81642419c7f83b70da9eb8d
- Source dataset
- uspto-grants-1992_10
- Patent number
- US05158936
Reaction notes
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