Dihydroxybenzenes

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Dihydroxybenzenes
Surname Catechol Resorcinol Hydroquinone
other names 1,2-dihydroxybenzene
o -dihydroxybenzene		 1,3-dihydroxybenzene
m -dihydroxybenzene		 1,4-dihydroxybenzene
p -dihydroxybenzene
Structural formula Structure of catechol Structure of resorcinol Structure of hydroquinone
CAS number 120-80-9 108-46-3 123-31-9
PubChem 289 5054 785
Molecular formula C 6 H 6 O 2
Molar mass 110.11 g mol −1
Physical state firmly
Melting point 105 ° C 111 ° C 170 ° C
boiling point 245 ° C 277 ° C 286 ° C
pK s 1 value 9.48 9.44 10.85
pK s 2 value 12.08 11.32 11.39
GHS
labeling
06 - Toxic or very toxic 08 - Dangerous to health
05 - Corrosive
danger
08 - Dangerous to health 07 - Warning
09 - Dangerous for the environment
danger
05 - Corrosive 08 - Dangerous to health
07 - Warning 09 - Dangerous for the environment
danger
H and P phrases 301 + 311-332-315-317-318-341 302-315-319-317-370-410 351-341-302-318-317-400
no EUH phrases no EUH phrases no EUH phrases
280-301 + 310
305 + 351 + 338-312 		260-273-280-308
311-333 + 313-337 + 313 		273-280
305 + 351 + 338-302 + 352-313

The dihydroxybenzenes belong to the group of phenols , consisting of a benzene ring with two hydroxyl groups  (-OH) as substituents . Their different arrangement results in three constitutional isomers with the empirical formula C 6 H 6 O 2 . They are best known by their common names, catechol , resorcinol and hydroquinone .

properties

The hydroquinone, which has the highest symmetry, has the highest melting point. Catechol and hydroquinone can be oxidized to quinones in an alkaline environment with formal release of protons and electrons . With resorcinol, however, the formation of a quinoid system is not possible.

See also

Individual evidence

  1. ↑ a b c Entry on catechol in the GESTIS substance database of the IFA , accessed on December 6, 2015(JavaScript required) .
  2. ↑ a b c Entry on resorcinol in the GESTIS substance database of the IFA , accessed on December 6, 2015(JavaScript required) .
  3. ↑ a b c Entry on hydroquinone in the GESTIS substance database of the IFA , accessed on December 6, 2015(JavaScript required) .
  4. ↑ a b CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .

Web links

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