Bromophenols

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In chemistry, bromophenols form a group of substances which are formally derived from phenol and bromobenzene . The structure consists of a benzene ring with a hydroxyl group  (–OH) and bromine  (–Br) as substituents . Their arrangement results in three constitutional isomers with the empirical formula C 6 H 5 BrO.

Bromophenols
Surname 2-bromophenol 3-bromophenol 4-bromophenol
other names o -Bromophenol m -bromophenol p -bromophenol
Structural formula Structure of 2-bromophenol Structure of 3-bromophenol Structure of 4-bromophenol
CAS number 95-56-7 591-20-8 106-41-2
PubChem 7244 11563 7808
Molecular formula C 6 H 5 BrO
Molar mass 173.02 g mol −1
Physical state liquid firmly
Melting point 3-7 ° C 28-32 ° C 61-64 ° C
boiling point 195-196 ° C 236 ° C 235-236 ° C
pK s value 8.42 9.11 9.34
GHS
labeling
02 - Highly / extremely flammable 07 - Warning

09 - Dangerous for the environment
Caution
07 - Warning
Caution
07 - Warning
Caution
H and P phrases 226-302-315-319-335-400 315-319-335 302-315
no EUH phrases no EUH phrases no EUH phrases
261-273-305 + 351 + 338 261-305 + 351 + 338 301 + 312 + 330

properties

4-bromophenol, which has the highest symmetry, has the highest melting point. The bromophenols are more acidic than phenol due to the −I effect of the bromine substituent. The pK s values are therefore correspondingly lower (phenol: 9.99).

presentation

2-Bromophenol can be obtained from phenol via the bromination of the sodium salt of 2,4-disulfonic acid.

Reaction scheme for the synthesis of 2-bromophenol

The preparation from 2-bromoaniline is also possible.

3-Bromophenol can be produced from nitrobenzene by bromination, diazotization and subsequent boiling of the diazonium salt .

Reaction scheme for the synthesis of 3-bromophenol

4-Bromophenol is obtained from phenol by bromination with elemental bromine.

Synthesis of 4-bromophenol

Individual evidence

  1. ↑ a b c data sheet 2-bromophenol from Sigma-Aldrich , accessed on November 3, 2016 ( PDF ).
  2. ↑ a b c data sheet 3-bromophenol from Sigma-Aldrich , accessed on November 3, 2016 ( PDF ).
  3. ↑ a b c data sheet 4-bromophenol from Sigma-Aldrich , accessed on November 3, 2016 ( PDF ).
  4. ↑ a b CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
  5. ↑ Ralph C. Huston and Murel M. Ballard: o-Bromophenol In: Organic Syntheses . 14, 1934, p. 14, doi : 10.15227 / orgsyn.014.0014 ; Coll. Vol. 2, 1943, p. 97 ( PDF ).
  6. ↑ Joachim Buddrus: Fundamentals of organic chemistry ; ISBN 978-3-11-014683-7 .
  7. ^ Association of authors: Organikum , 19th edition, Johann Ambrosius Barth, Leipzig · Berlin · Heidelberg 1993, ISBN 3-335-00343-8 , pp. 331-332.