Trihydroxybenzoic acids
In chemistry, the trihydroxybenzoic acids form a group of aromatic compounds that are derived from both benzoic acid and trihydroxybenzenes . The structure consists of a benzene ring with an attached carboxy group (-COOH) and three hydroxyl groups (-OH) as substituents . Their different arrangement results in six constitutional isomers with the empirical formula C 7 H 6 O 5 .
Trihydroxybenzoic acids | ||||||||
Surname | 2,3,4-trihydroxybenzoic acid | 2,3,5-trihydroxybenzoic acid | 2,3,6-trihydroxybenzoic acid | 2,4,5-trihydroxybenzoic acid | 2,4,6-trihydroxybenzoic acid | 3,4,5-trihydroxybenzoic acid | ||
other names | 4-pyrogallol carboxylic acid | Phloroglucinic acid | Gallic acid | |||||
Structural formula | ||||||||
CAS number | 610-02-6 | 33580-60-8 | 16534-78-4 | 610-90-2 | 83-30-7 | 149-91-7 | ||
PubChem | 11874 | 134974 | 134719 | 69129 | 66520 | 370 | ||
ECHA InfoCard | 100.009.279 | 100.001.334 | 100.005.228 | |||||
Molecular formula | C 7 H 6 O 5 | |||||||
Molar mass | 170.12 g mol −1 | |||||||
Physical state | firmly | |||||||
Melting point | ~ 205 ° C | 205 ° C | 253 ° C (decomposition) | |||||
pK s value (25 ° C) | 1.68 | 3.13 | ||||||
GHS labeling |
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not a hazardous substance according to GHS |
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H and P phrases | 315-319-335 | 315-319-335 | no H-phrases | |||||
no EUH phrases | no EUH phrases | no EUH phrases | ||||||
261-305 + 351 + 338 | 261-305 + 351 + 338 | no P-phrases |
Individual evidence
- ↑ a b data sheet 2,3,4-Trihydroxybenzoic acid from Sigma-Aldrich , accessed on May 9, 2012 ( PDF ).
- ↑ a b data sheet 2,4,6-Trihydroxybenzoic acid from Sigma-Aldrich , accessed on May 9, 2012 ( PDF ).
- ↑ a b Entry on Gallic acid in the ChemIDplus database of the United States National Library of Medicine (NLM), accessed on July 31, 2018 or earlier.
- ^ D'Ans-Lax: Pocket book for chemists and physicists , 3rd edition, Volume 1, Springer-Verlag, Berlin-Göttingen-Heidelberg 1967 ( ChemieOnline - pK b and pK s values ).
- ↑ Entry on 3,4,5-trihydroxybenzoic acid in the GESTIS substance database of the IFA , accessed on December 25, 2019(JavaScript required) .