2-аминонафталин-1-сульфоновой кислоты

Химические свойства

Grey white to light pink powder. 2-Aminonaphthalene-1-sulfonic acid [81-16-3].  Tobias acid, C10H9NO3S, Mr 223.24, is sparingly soluble in water but the sodium salt is readily soluble. Coupling with diazo compounds takes place in the 1-position with elimination of the sulfonic acid group.

Использование

Azo dye intermediate, optical brighteners. Sulfonation with oleum gives 2-aminonaphthalene-1,5-disulfonic acid, which can be desulfonated to produce 2-aminonaphthalene-5- sulfonic acid. Tobias acid is used as a diazo component in acid dyes (e.g., C.I. Acid Yellow 19), red reactive dyes, and pigments such as the important Lithol Reds, [e.g., C.I. Pigment Red 49]. The free acid of C.I. Pigment Red 49 is also remarkably insoluble and can be used as a pigment.

Общее описание

2-Amino-1-naphthalenesulfonic acid is a manufacturing intermediate in the monosulfo monoazo color additive D&C Red No. 34 and its lakes.

Методы очистки

Crystallise the acid under nitrogen from boiling water and dry it in a steam oven [Bryson Trans Faraday Soc 47 522, 527 1951]. [Beilstein 14 III 2240, 14 IV 2792.]