4-Hydroxybenzenesulphonic Acid, also known by its molecular formula C6H6O4S, stands as an organic sulfonic acid derived from phenol. Recognized in the chemical industry as a vital raw material, this compound holds HS Code 290820, guiding its classification in global trade. In the laboratory or production space, this substance appears in different forms, including solid, powder, crystalline flakes, liquid solutions, and a less common pearl presentation, each offering advantages depending on the required manufacturing process.
In terms of physical appearance, 4-Hydroxybenzenesulphonic Acid commonly shows up as white to pale yellow crystals or flakes, although powder and solution forms also circulate for ease of application. Strong hygroscopic nature attracts and retains water, requiring careful storage and handling. The substance carries a characteristic density range of about 1.46 g/cm3 when assessed as a solid at room temperature. Owing to its high solubility in water and polar solvents, it delivers significant value in dye manufacturing, textile treatment, and as a precursor in organic synthesis. The acid exhibits a sharp acidic taste, which calls for robust safety controls.
The molecule centers on a benzene ring, with a hydroxyl group at position 4 and a sulfonic acid group at another, bringing together both reactivity and functionality. Its structural simplicity pairs with remarkable versatility, allowing it to serve as a starting point for various sulfonated aromatic compounds. As a direct result, industries often pick it when requiring stability in acidic solutions and a predictable chemical backbone.
Manufacturers and buyers examine specifications such as purity (generally above 98% for industrial use), moisture content, physical form, color, and trace metal presence. These details affect both the safety and utility of the product. For instance, powder forms make precise dosing easier, while flakes ease dissolution into batch processes. Crystal and pearl versions are less dusty, which minimizes inhalation risk in bulk handling. Liquid and solution forms become essential for pumping and continuous processing.
Dye and pigment industries rely heavily on 4-Hydroxybenzenesulphonic Acid for synthesizing colorants, especially azo-based dyes. Textile processing often needs this compound for sulfonation, which enhances fiber interaction and color fastness. Water treatment facilities use it for specialty resin manufacture, targeting selective ion exchange and purification. Lab technicians select it in organic synthesis pathways for preparing complex molecules or specific intermediates.
Dealing with 4-Hydroxybenzenesulphonic Acid requires strict safety measures. Exposure to its dust or solutions may irritate the skin, eyes, or respiratory tract. Prolonged or repeated exposure can cause dermatitis or exacerbate respiratory issues, especially in spaces lacking adequate ventilation. Chemical burns become a risk if undiluted product contacts mucous membranes. Material Safety Data Sheets classify it as an irritant, not strictly toxic but decidedly hazardous in concentrated form. Workers should use gloves, goggles, and approved respirators when handling bulk product. Industrial sites keep eyewash stations and emergency showers in active use areas. Storage demands airtight containers, dry conditions, and cool temperatures to avoid clumping or pollution of the product.
Environmental safety matters as much as personal protection. Modern factories process waste streams containing 4-Hydroxybenzenesulphonic Acid through neutralization tanks and biological treatment units to cut the risk of waterway contamination. Dilute disposals lower acute toxicity, yet persistent high loads may threaten aquatic biology due to acidity and potential for secondary compound formation. Regulatory requirements guide safe discharge, with most authorities setting strict limits for chemical oxygen demand (COD) and sulfonic residues. Recycling options include reclaiming and purifying spent material for lower-tier industrial applications, cutting the lifecycle environmental burden.
Handling solid and powder forms exposes technicians to dust and spillage. Automated dosing equipment and enclosed transfer systems can contain product, improving workplace hygiene. Regular air monitoring and surface cleaning help maintain a low exposure environment. Where liquid or solution forms dominate, closed-loop handling and spill containment prevent environmental leaks and worker contact. Proper training in emergency response prepares teams for accidental exposure or chemical release, while plant designers can install redundant ventilation systems for any space with significant airborne concentration risks. Producers who invest in on-site purification lower potential downstream waste and tap into circular chemical economies, redefining how industrial chemistry supports both workers and the planet.
