Chlorophenols

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Chlorophenols
Surname 2-chlorophenol 3-chlorophenol 4-chlorophenol
other names 2-CP
o -chlorophenol
1-chloro-2-hydroxybenzene
1-oxy-2-chlorobenzene 		3-CP
m -chlorophenol
1-chloro-3-hydroxybenzene
1-oxy-3-chlorobenzene 		4-CP
p -chlorophenol
1-chloro-4-hydroxybenzene
1-oxy-4-chlorobenzene
Structural formula Structure of 2-chlorophenol Structure of 3-chlorophenol Structure of 4-chlorophenol
CAS number 95-57-8 108-43-0 106-48-9
25167-80-0 (mixture of isomers)
PubChem 7245 7933 4684
Molecular formula C 6 H 5 ClO
Molar mass 128.56 g mol −1
Physical state liquid firmly
Brief description colorless liquid
with a pungent odor 		colorless crystal needles
with a phenol-like odor
Melting point 7 ° C 33-35 ° C 43 ° C
boiling point 174 ° C 214 ° C 220 ° C
density 1.26 g cm −3 1.25 g cm −3 1.31 g cm −3
Vapor pressure 2.3 mbar (20 ° C) 0.23 mbar (20 ° C) 0.15 mbar (20 ° C)
pK s value 8.48 9.08 9.38
solubility slightly soluble in water (27–29 g / l at 20 ° C)
Flash point 85 ° C 120 ° C 121 ° C
GHS
labeling
07 - Warning 09 - Dangerous for the environment
Caution
H and P phrases 302-312-332-411
no EUH phrases
273 273-280 273-302 + 352
Toxicological data 40 mg kg −1 ( LD 50 ,  rat ,  oral ) 570 mg kg −1 ( LD 50 ,  rat ,  oral ) 670 mg kg −1 ( LD 50 ,  rat ,  oral )

In chemistry , the chlorophenols form a group of substances that are derived from both phenol and chlorobenzene . The structure consists of a benzene ring with attached hydroxyl group  (-OH) and chlorine  (-Cl) as substituents . Their different arrangement results in three constitutional isomers with the empirical formula C 6 H 5 ClO.

properties

Chlorophenols are poorly water-soluble, non-volatile, toxic, sometimes carcinogenic compounds that are often used as wood preservatives , herbicides and fungicides , for bleaching cellulose in paper production and as intermediates in the synthesis of drugs and dyes. Since they are chemically very stable, they accumulate in the food chain . When chlorophenols are heated, polychlorinated dibenzodioxins can be formed with the elimination of hydrogen chloride .

The 4-chlorophenol, which has the highest symmetry, has the highest melting point. The chlorophenols have a higher acidity compared to phenol due to the −I effect of the chlorine substituent. The pK s values are therefore correspondingly lower (phenol: 9.99).

use

2-chlorophenol is used in the manufacture of drugs and dyes as well as a disinfectant and appears as a pollutant in groundwater. 3-chlorophenol and 4-chlorophenol are used as intermediate products in the manufacture of pharmaceuticals and dyes and as disinfectants.

More connections

The expanded group of chlorophenols (CP) includes a total of 19 chemical compounds that can be produced in phenol by substituting chlorine for the hydrogen atoms .

Depending on the number of chlorine atoms, one differentiates:

With the exception of 2-chlorophenol , all compounds of the group are solid at room temperature.

Individual evidence

  1. ↑ a b c d e f g h Entry on 2-chlorophenol in the GESTIS substance database of the IFA , accessed on October 14, 2012(JavaScript required) .
  2. ↑ a b c d e f g h Entry on 3-chlorophenol in the GESTIS substance database of the IFA , accessed on October 14, 2012(JavaScript required) .
  3. ↑ a b c d e f g h Entry on 4-chlorophenol in the GESTIS substance database of the IFA , accessed on October 14, 2012(JavaScript required) .
  4. ↑ a b CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .

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