4-aminobenzenesulfonic acid

Chemical Composition and Structure

Sulfanilic acid typically exists as a white to off-white crystalline solid with a slight odor. It is soluble in water and has a melting point around 288-290°C. Sulfanilic acid has the chemical formula C6H7NO3S, with a molecular weight of 173.19 g/mol. It contains an amino group (NH2) and a sulfonic acid group (SO3H) attached to a benzene ring.

Uses and Mechanism of Action

In chemistry, sulfanilic acid serves as a precursor in the synthesis of various compounds, including dyes, pharmaceuticals, and coordination polymers.^[4]
In dosimetry, sulfanilic acid is used as a dosimeter in low-dose ionizing radiation (<30?Gy), exhibiting electron spin resonance (ESR) signals proportional to the radiation dose.^[2]
In spectroscopic studies, sulfanilic acid is employed to explore electronic and vibrational properties through periodic and non-periodic density functional theory (DFT) calculations.^[1]
In biology and environmental science, sulfanilic acid and its derivatives are studied for potential antibacterial properties and their role in photocatalysis for environmental remediation.

History and Development

Sulfanilic acid has been used industrially for many years, particularly in the dye industry. Its synthesis from readily available starting materials has made it a versatile compound for various applications.

Analysis Method

The purity and identity of sulfanilic acid can be determined using various spectroscopic techniques such as FTIR, Raman spectroscopy, UV-Vis spectroscopy, and ESR spectroscopy. These methods help ensure product quality and consistency, as well as provide insights into its molecular structure and properties.

Production Methods

Sulfanilic acid is primarily synthesized from aniline and concentrated sulfuric acid. It can also be obtained as a byproduct in the production of aniline and is widely available commercially.^[3]

Synthesize

Sulfanilic acid can be used for the determination of nitrite. Biochemical Research. Organic Synthesis. Sulfanilic acid is an important intermediate of sulfonamide drugs. This product has strong antibacterial effect on hemolytic streptococcus, meningitis and coccus, but due to poor efficacy and high toxicity, it is rarely used for oral administration. It is also rarely used. It is used as an intermediate for the synthesis of other sulfonamides, and is also used as a raw material for the synthesis of agricultural "Huangcaoling" abroad. Sulfanilic acid can also be used as an analytical reagent, such as a reagent for the photometric determination of nitrite and sodium nitroferricyanide. For biochemical research, organic synthesis and pharmaceutical industry. Sulfanilic acid is the main raw material for synthesizing sulfonamides. In addition to preparing crystalline sulfonamides for external anti-inflammatory, it can also synthesize other sulfonamides such as sulfamidine, sulfamethoxazine, and sulfamethazine.

Definition

ChEBI: An aminobenzenesulfonic acid that is aniline sulfonated at the para-position.

Application

As the compound readily form diazo compounds, it is used to make dyes and sulpha drugs . This property is also used for the quantitative analysis of nitrate and nitrite ions by diazonium coupling reaction with N-(1-Naphthyl) ethylene diamine , resulting in an azo dye, and the concentration of nitrate or nitrite ions were deduced from the color intensity of the resulting red solution by colorimetry. It is also used as a standard in combustion analysis.

General Description

White powder with faint purple tinge. Grayish-white flat crystals. Becomes anhydrous at around 212°F. Low toxicity (used medicinally).

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Sulfanilic acid is an amino acid. Reacts weakly with both acids and bases.

Fire Hazard

Flash point data for Sulfanilic acid are not available, however Sulfanilic acid is probably combustible.

Synthesis

Sulfanilic acid can be produced by sulfonation of aniline.

Purification Methods

Crystallise the acid (as dihydrate) from boiling water. Dry it at 105o for 2-3hours, then over 90% H2SO4 in a vacuum desiccator. The S-benzylisothiuronium salt has m 187o (from aqueous EtOH). [Beilstein 14 IV 2655.]