Methods of Manufacturing

Chlorination of phenol; from chloroaniline through diazonium salt
... From diazotized p-chloroaniline by chlorination of phenol.
Mfr by selective reduction of chlorobromophenols..
From p-nitrosophenol by a modification of Sandmeyer reaction.
Phenol + sulphuryl chloride (ring chlorination)
The chlorination of melted phenol using chlorine gas yields a mixture of ortho and para monochlorophenols with an ortho/para ratio of about 0.54 (35/65), which is scarcely dependent on temperature. The distribution between the two isomers depends especially on the nature of the chlorination reagent and the characteristics of the reaction medium. The formation of 2-chlorophenol is favored by an aprotic nonpolar solvent medium, such as hexane, carbon tetrachloride, or dichloroethane. The ortho/para ratio is also higher for reactions with a low concentration of phenol and a high temperature. The chlorination of a 5% solution of phenol in perchloroethylene at 110 deg C in the presence of 0.01 wt% diisopropylamine gives a very high ortho/para ratio, about 15. Chlorinations using aqueous sodium hypochlorite at pH 10, tert-butyl hypochlorite and alkali phenolates dispersed in an anhydrous medium, or chlorine in acetic acid in the presence of acetic anhydride also favor the formation of 2-chlorophenol. The formation of 4-chlorophenol is favored by chlorination in a polar medium, such as acetonitrile, nitrobenzene, or ether. Substitution in the para position is also strongly favored by the use of sulfuryl chloride as a chlorinating agent (ortho/para = 0.35).

U.S. Production

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. Year Production Range (pounds) 1986 >500 thousand - 1 million 1990 10 thousand - 500 thousand 1994 10 thousand - 500 thousand 1998 10 thousand - 500 thousand 2002 10 thousand - 500 thousand