A process for the preparation of 1-amino-2-ethoxy-naphthalene-6-sulphonic acid from 2-hydroxy-naphthalene-6-sulphonic acid which comprises: A. contacting 2-hydroxy-naphthalene-6-sulphonic acid with at least an equimolar amount of an alkali metal nitrite in aqueous solution or suspension in the presence of hydrochloric acid, solution or suspension having a pH in the range of 2 to 5 and being at a temperature of 0.degree. to 20.degree. C.; B. reducing the reaction product of step A in an aqueous suspension by contacting the same with excess iron in the presence of at least an equivalent amount of iron-II ions, relative to the reaction product obtained according to step A, in the presence of a mineral acid at a temperature from 50.degree. to 120.degree. C., and treating the thus-obtained reaction mixture with aqueous alkali metal hydroxide in the presence of iron oxide; C. contacting the product of step B with excess acetic anhydride in an aqueous solution or suspension at a pH in the range of 3 to 10 at a temperature from 0.degree. to 100.degree. C.; D. contacting the product of step C with an ethylating agent in the presence of an acid binding agent in an aqueous-organic solvent or diluent in a pH range from 8 to 14 at a temperature from 20.degree. to 150.degree. C.; and E. deacetylating the product of step D by contacting the same at reflux with an aqueous alkali metal hydroxide.
从2-羟基-
萘-6-
磺酸制备1-
氨基-2-乙氧基-
萘-6-
磺酸的过程包括:A.在氢
氯酸存在下,将2-羟基-
萘-6-
磺酸与至少等量的碱
金属
亚硝酸盐在
水溶液或悬浮液中接触,溶液或悬浮液的pH在2至5之间,温度为0℃至20℃;B.在过量的
铁和至少相当于步骤A得到的反应产物的
铁II离子存在下,在矿物酸的存在下,将步骤A的反应产物在
水悬浮液中还原,温度为50℃至120℃,并在
铁氧化物的存在下处理所得到的反应混合物;C.在
水溶液或悬浮液中,将步骤B的产物与过量的
乙酸酐在pH为3至10的温度为0℃至100℃的条件下接触;D.在
水有机溶剂或稀释剂中,在pH为8至14,温度为20℃至150℃的条件下,将步骤C的产物与乙基化试剂在酸性结合剂的存在下接触;E.通过在回流条件下与
水合
金属氢氧化物接触,对步骤D的产物进行去乙酰化。