Intermediates specifically for dyes

Products under this heading are of relatively small tonnage and are often made by dye manufacturers themselves for internal use arid for sale to other dye manufacturers where competitive interests are compatible. 

2 Intermediates derived from 2-chloro- and 4-chloronitrobenzene. These two products are produced simultaneously when chlorobenzene is nitrated with mixed acid (HNO3, H2O, H2SO4, 35 12 53). The 4-chloro compound predominates (65%), the remainder being the 2-chloro derivative. The isomers are separated by a combination of vacuum fractional distillation and fractional crystallization. On further nitration of either isomer 2,4-dinitrochlorobenzene is the product 1,4-dichlorobenzene gives 2,5-dichlo- 

5 5-amino-2-o-toluidinobenzene sulphonic acid diphenylamine-2-sulphonic acid azo 

7 4-chloroaniline-2-sulphonic acid 4-aminochlorobenzene-3-sulphonic acid azo 

2 2-aminotoluene-5-sulphonic acid (N.B. in the lUPAC, name for nos. 2, 4, 7, methylbenzene merely replaces toluene)  

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