Sulfanilic Acid

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sulfanilic acid

[¦səl·fə¦nil·ik ′as·əd]
(organic chemistry)
C6H4NH2·SO3H·H2O Combustible, grayish-white crystals slightly soluble in water, alcohol, and ether, soluble in fuming hydrochloric acid; chars at 280-300°C; used in medicine and dyestuffs and as a chemical intermediate.

Sulfanilic Acid


(or p-aminobenzenesulfonic acid), a colorless crystalline compound that decomposes at 280°–300°C. It is sparingly soluble in water; 1 g dissolves in 100 g of water at 20°C.

Sulfanilic acid is an inner salt, in which the amino group is neutralized by the sulfo group. Therefore, the acid does not form salts with mineral acids, but its sulfo group may be neutralized by

bases—for example, with the formation of the sodium salt H2N—C6H4SO3Na.

Sulfanilic acid is produced by heating aniline sulfate, C6H5NH2·½H2SO4, at 180°–200°C. Diazotization of sulfanilic acid yields diazobenzenesulfonic acid, Sulfanilic Acid, which is widely used in the production of azo dyes. The amide of sulfanilic acid, H2H—C6H4—SO2NH2 (sulfanilamide), is used in medicine, where it is called Streptocid album. Some of the derivatives of sulfanilamide, including Albucid, sulfonamide (Sul’gin), Sulfidine, sulfamethazine, and sulfazole, or sulfamethylthiazole, are also used in medicine. In the laboratory, sulfanilic acid is used for the determination of nitrites and the detection of several metals, such as osmium and ruthenium.

References in periodicals archive ?
The infrared spectra of the synthesized reactive dyes based on -acid, sulfanilic acid and cyanuric chloride showed absorption peaks owing to O-H, N-H, Ar-H, CH2, C=O, C=C, C=N, NO2, SO3H, N=N and C-Cl stretching and bending vibrations at 3435-3467, 3032-3072, 2838-2963, 1755, 1625-1653, 1568-1589, 1512-1526, 1433-1465, 1125-1070, 750-787 and 680-689cm-1, respectively.
Two series of new monoazo bis reactive dyes (6a-h and 11a-h) have been synthesized in high yields from 4-NAP, H-acid, sulfanilic acid and -acid, respectively and examined for different properties.
From the representative structures of RXR protein complex with sulfanilic acid after MD simulation displayed in Figure 9(b), it is illustrated that the group of sulfonyl hydroxide of sulfanilic acid maintains the H-bonds with key residues Arg316 and Ala327 and the phenyl group next to sulfonyl hydroxide keeps the [pi] interaction with residue Phe313.
Elevated D/L-HoCys levels are a potent inhibitor of [Na.sup.+]-dependent cysteine sulfanilic acid uptake into chick astrocytes and neurons [13] and should slow de novo brain taurine synthesis [11,13].
Reagent 2 was prepared by dissolving 5 g of sulfanilic acid in 500 mL of 3 mol/L HCl.
43 Sulfanilic acid is a gray-white to white crystalline solid.
This leads to the formation of sulfanilic acid and 1-amino-2-naphthol [27-29].
In this method nitrite reacts under acidic conditions with sulfanilic acid to form a diazoniumcation which couples with the aromatic amine 1-napthlylamine to produce red-violet coloured water soluble azo dye [13].
The nitrite, resulted from the oxidation of hydroxylammonium by superoxide anions generated in the xanthine-xanthine oxidase system, was determined spectrophotometrically by the reaction with sulfanilic acid and [alpha]-naphthyla-mine.