Sulfuric Acid → Anthraquinone
Reaction equation
[C:1]([C:9]1[CH:17]=[CH:16][CH:15]=[CH:14][C:10]=1[C:11](O)=[O:12])(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.S(=O)(=O)(O)O>>[CH:14]1[C:10]2[C:11](=[O:12])[C:7]3[C:2](=[CH:3][CH:4]=[CH:5][CH:6]=3)[C:1](=[O:8])[C:9]=2[CH:17]=[CH:16][CH:15]=1Participants
Reactant 2
Product 1
Procedure
In spite of its already high degree of purity, the direct mixing of the crude o-benzoyl-benzoic acid with hot concentrated sulfuric acid gives a strongly colored anthraquinone contaminated with decomposition products. The crude acid is therefore esterified with methanol, and the methyl ester separated from the by-products through a distillation. The esterification may be effected in the conventional manner in the presence of acid catalysts such as hydrochloric, sulfuric or p-toluenesulfonic acids, or alternatively without catalysts under pressure at temperatures above 200° C. The pure o-benzoyl-benzoic acid methyl ester distills off in the range 177°-181° C. under a pressure of 8 Torr. It solidifies to colorless crystals with a melting point of 52.5° C.
Sources & evidence
- ORD record
- ord-aacdff4a8bb044febf172b3a28f0e5f3
- Source dataset
- uspto-grants-1980_01
- Patent number
- US04185023
Reaction notes
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