PROCESS FOR THE PREPARATION OF MONO ALKALI SALT OF 1-AMINO-8-NAPHTHOL-3,6-DISULFONIC ACID

摘要

In alk. fusion of Koch acid to H acid mono-Na salt (I), the initial and final alkali concentrations were maintained at 20-9 and 25-35 %, resp. For example, in the alkali fusion of crude Koch and tri-Na salt, the NaOH concentration was maintained at 27.0 % throughout the reaction by addition of additional NaOH during the reaction to obtain I in 83 % yield. When the addition of additional NaOH was omitted, the final NaOH concentration in the reaction mixture was 22.1% and the I yield was 73.5 %.