FORMULA  . 2-oxy-8-sulphonic From p-naphthol and concen-

Sodium salt soluble in (Baeyer's acid) trated sulphuric acid at strong alcohol . 50°–60° C . 2-oxy-6-sulphonic From ,Q-naphthol and concen- Sodium salt insoluble in (Schaffer's acid) trated sulphuric at 100° C. alcohol . 2-oxy-7-sulphonic By fusion of naphthalene 2.7- Very soluble in water (F-acid) disul phonic acid with caustic and alcohol . soda at 200°–250° C . 2-oxy-3.6-disulphonic Both R- and G-acid from f - The sodium salts separ- (R-acid) naphthol and concentrated ated by crystalliza- sulphuric acid at Ioo°– tion . R-salt insoluble 110°C. in alcohol ; G-salt soluble . 2-oxy-6.8-disulphonic (G-acid) 2-oxy-3.6.8-trisulphonic From A-naphthol and fuming Alkaline solutions show sulphuric acid at 14o°–16o°C. green fluorescence . a-naphthoquinone-oxime, formed by the action of nitrous acid on a-naphthol or of hydroxylamine hydrochloride on a-naphthoquinone (H . Goldschmidt and H . Schmidt, Ber., 1884, 17 p .

2064) ; and 2-nitroso-a-naphthol (i3-naphthoquinone-oxime), formed by the action of hydroxylamine hydrochloride on (3-naphthoquinone .