Лако-красочные материалы — производство

These two important sulfonic acids can be prepared in various ways. Three methods are used for preparing у acid, while J acid, so far as is known, is prepared only from naphthylamine, although by varying procedures. The starting material in all cases is /З-naphthol; the reac­tions involved are shown in the following scheme. We shall describe here only the preparations starting from /З-naphthylamine. The pro­cesses starting from ^-naphthol and its sulfonic acid derivatives are de­scribed briefly in the technical observations following the preparation of J acid.

OH

I

*

OH

2- Amino-8-naphthol-6-
sulfonic acid (Gamma acid)

OH

2-Amino-5- naphthol-7-
sulfonic acid (iso-Gamma
acid, J acid)