反应详情

treating the resultant aqueous solution of the ammonium salt of oxy-Tobias acid, without increasing the concentration beforehand, with NH3 and concentrated (NH4)2SO3 or (NH4)HSO3 solution in the temperature range from 120° to 150° C. and at a pressure of 10 to 20 bar for 4 to 12 hours until the pH value is 9 to 12, to give the ammonium salt of 2-amino-1-naphthalenesulfonic acid (Tobias acid), and, after stripping off NH3 and removal of 2-naphthylamine by extraction with an aromatic hydrocarbon,

1. temperaturewithout increasing the concentration beforehand