Tobias Acid

Public-database records for Tobias Acid (CAS 81-16-3), reproduced here for independent cross-checking.

Safety classification and hazard statements

Regulatory listings

Physical description and handling notes

• White solid; [HSDB] Light orange crystalline powder; [MSDSonline]
• WHITE NEEDLES
• Anhydrous scales from hot water; hydrated needles from cold water
• Slightly sol in cold water; more sol in hot water; very slightly sol in alcohol, ether
• When heated to decomp it emits very toxic fumes of /nitrogen oxides and sulfur oxides/.

Reported physical properties

How this substance is indexed

Documented uses

• Used in optical brighteners and as a diazo component in acid dyes , red reactive dyes, and pigments; [HSDB]
• Tobias acid is used as a diazo component in acid dyes (eg, C.I. Acid Yellow 19), red reactive dyes, and pigments such as the important Lithol Reds, (eg, C.I. Pigment Red 49).
• Azo dye intermediate, optical brighteners
• PREPD BY SULFONATION OF 2-NAPHTHYLAMINE: TINKER, HANSEN, US PATENT 1,969,189 (1934 TO DU PONT).
• Sulfonation of beta-naphthol with chlorosulfonic acid in nitrobenzene at 0 °C followed by heating the resulting 1-sulfonic acid with ammonium hydrogen sulfite and ammonia at 145-150 °C. Purification is by precipitation from dilute solution of the sodium salt.
• By amination of the appropriate hydroxynaphthalenesulfonic acid.

Names this substance appears under

81-16-3; 2-AMINO-1-NAPHTHALENESULFONIC ACID; Tobias acid; 2-Naphthylamine-1-sulfonic acid; Kyselina tobiasova; 1-Naphthalenesulfonic acid, 2-amino-; F9QKW1FCE0; Kyselina 2-naftylamin-1-sulfonova; DTXSID7020922; NSC-5523; DTXCID90922; RefChem:463279; 201-331-5; 2-aminonaphthalene-1-sulfonic acid; CCRIS 9048; MFCD00003988

Computed molecular descriptors

Database abstract

Tobias Acid · CAS 81-16-3 · C10H9NO3S. UNII F9QKW1FCE0. 溶解度: In water, 4,100 mg/l @ 20 °C; LogP: log Kow= -1.16; LogP: -1.16.

Source: PubChem / Wikidata; the batch COA governs where values differ.