Trihydroxybenzoic acids

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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 2,3,4-Trihydroxybenzoic acid. Svg 2,3,5-Trihydroxybenzoic acid. Svg 2,3,6-Trihydroxybenzoic acid. Svg 2,4,5-trihydroxybenzoic acid. Svg 2,4,6-Trihydroxybenzoic acid. Svg Gallic acid.svg
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
07 - Warning
Caution
07 - Warning
Caution 		not a hazardous substance
according to GHS
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

  1. ↑ a b data sheet 2,3,4-Trihydroxybenzoic acid from Sigma-Aldrich , accessed on May 9, 2012 ( PDF ).
  2. ↑ a b data sheet 2,4,6-Trihydroxybenzoic acid from Sigma-Aldrich , accessed on May 9, 2012 ( PDF ).
  3. ↑ 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.
  4. ^ 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 ).
  5. ↑ Entry on 3,4,5-trihydroxybenzoic acid in the GESTIS substance database of the IFA , accessed on December 25, 2019(JavaScript required) .

See also