Trihydroxybenzenes

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Trihydroxybenzenes
Surname 1,2,3-trihydroxybenzene 1,2,4-trihydroxybenzene 1,3,5-trihydroxybenzene
other names Pyrogallol
vic -Trihydroxybenzol		 Hydroxyhydroquinone
asym -Trihydroxybenzol		 Phloroglucinol
sym -Trihydroxybenzene
Structural formula Structure of pyrogallol Structure of hydroxyhydroquinone Structure of phloroglucinol
CAS number 87-66-1 533-73-3 108-73-6
PubChem 1057 10787 359
Molecular formula C 6 H 6 O 3
Molar mass 126.11 g mol −1
Physical state firmly
Brief description colorless needles
 		 colorless to
light beige solid
Melting point 131-135 ° C 140 ° C 217-220 ° C
boiling point 309 ° C Decomp.
pK s value 9.01 8.45
solubility 400 g / l (20 ° C) 10 g / l (20 ° C)
GHS
labeling
08 - Dangerous to health 07 - Warning
Caution
05 - Corrosive 07 - Warning
danger
08 - Dangerous to health
Caution
H and P phrases 302-312-332-341-412 302-315-318-335 315-319-335
no EUH phrases no EUH phrases no EUH phrases
273-281-302 + 352-308 + 313 261-280-305 + 351 + 338 302 + 352-305 + 351 + 338

The trihydroxybenzenes form a group of substances consisting of a benzene ring with three hydroxyl groups  (-OH) as substituents . Their different arrangement results in three constitutional isomers with the empirical formula C 6 H 6 O 3 . They are also known by their common names pyrogallol (1,2,3-trihydroxybenzene), hydroxyhydroquinone (1,2,4-trihydroxybenzene) and phloroglucinol (1,3,5-trihydroxybenzene).

properties

1,2,3- and 1,2,4-trihydroxybenzene can be oxidized to quinones in an alkaline medium analogous to the dihydroxybenzenes with formal release of protons and electrons . With 1,3,5-trihydroxybenzene, however, the formation of a quinoid system is not possible (cf. 1,3-dihydroxybenzene ).

See also

Individual evidence

  1. ↑ a b c d Entry on pyrogallol in the GESTIS substance database of the IFA , accessed on April 22, 2017(JavaScript required) .
  2. ↑ a b data sheet 1,2,4-benzenetriol from Sigma-Aldrich , accessed on April 22, 2017 ( PDF ).
  3. ↑ a b c Entry on Phloroglucin in the GESTIS substance database of the IFA , accessed on April 22, 2017(JavaScript required) .
  4. ↑ CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .

Web links

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