Question

what is the mechanism of the Azo dye prepared using B4

Anilines NH2 LINH HOS SO,H C Aniline-2-sulfonic acid HO,S A Sulfanilic acid B Aniline-3-sulfonic acid 1 1-Naphthol 2-Naphthol Phenols OH COH C3 3 Salicylic acid HO 4-Chloro-3-methylphenol A4 By C4 Figure 4.

Answer 1

Mechanism for the formation of the DYE B4 consisting of the following set of reaction conditions:

(i) Diazotisation of the aniline (here is the 3-aminosulphonic acid) gives the correspomding Diazonium salt, this is achieved by using SODIUMNITRITE in ACIDIC MEDIUM SUCH AS HCl.

(ii) Coupling of the diazotised salt with the 4-chloro 3- methyl phenol, in the presence of base at low temperature such as 0-5* C. results the formation of the B4.

The mechanism of the B4 formation is given as follows,
cl NH 4ses el hovetiedion t В tasphing wi th 4 н 4 meta amim 4-chhrm-3m th phinol salphani acid Pas- Mechanism o Dnz2ohzsan Br eneal NHA A NEN CIO Hel Sog H Mech r Na-0-N 0 + Nacl. H-O-NIO H-0-N=0 H-ONo - H2O N=O 7N =0 Nitrosonium m NH H H S03 NC l H Se

H So S03H -H20 Diazoninm salt" inmpling meatin S0g H el он NEN + 273-278 K HO ane of the Reeonanse Pom 1H Sos NEN H H S NN