4-methylbenzenesulfonic acid

4-methylbenzenesulfonic acid is an organic sulfonic acid compound with the molecular formula C7H8O3S and CAS number 104-15-4. This aromatic sulfonic acid features a methyl group attached to the benzene ring at the para position relative to the sulfonic acid group. With a molecular weight of 172.2 g/mol, it appears as a white crystalline solid that is highly soluble in water and polar solvents due to its ionic nature.

4-methylbenzenesulfonic acid is a white to off-white crystalline solid at room temperature with high water solubility due to its sulfonic acid functional group. The compound is hygroscopic and readily dissolves in polar solvents including alcohols. It exhibits strong acidic properties with a low pKa value, making it a strong organic acid. The substance is stable under normal conditions but should be protected from moisture to prevent caking.

4-methylbenzenesulfonic acid is primarily used as a catalyst in organic synthesis reactions, particularly in esterification and polymerization processes. It serves as an intermediate in the production of dyes, pharmaceuticals, and specialty chemicals. The compound is also utilized in electroplating applications and as a curing agent for certain resins. Additionally, it finds application in the synthesis of surfactants and as a pH adjustment agent in various industrial processes.

4-methylbenzenesulfonic acid requires careful handling as it can cause skin and eye irritation (GHS07 pictogram). Essential personal protective equipment includes chemical-resistant gloves, safety goggles, and protective clothing to prevent direct contact. Ensure adequate ventilation in work areas to minimize inhalation exposure. Avoid generating dust and wash hands thoroughly after handling. In case of potential respiratory exposure, use appropriate respiratory protection in poorly ventilated areas.

4-methylbenzenesulfonic acid should be stored in a cool, dry, well-ventilated area away from direct sunlight and moisture sources. Keep containers tightly closed in original packaging to prevent contamination and moisture absorption. Store away from incompatible materials such as strong bases, oxidizing agents, and metals. Maintain storage temperatures below 25°C when possible and ensure proper labeling according to CLP regulation requirements including GHS07 pictogram and warning signal word.

4-methylbenzenesulfonic acid contact requires immediate first aid measures due to its irritating properties. For skin contact, immediately remove contaminated clothing and rinse affected area with plenty of water for at least 15 minutes. In case of eye contact, flush immediately with clean water for 15-20 minutes and remove contact lenses if present. If inhaled, move person to fresh air immediately. Seek medical attention if irritation persists or develops after any exposure route.

4-methylbenzenesulfonic acid disposal must comply with local and national hazardous waste regulations as it is classified as corrosive (ADR Class 8). The substance should never be disposed of down drains or in regular waste streams. Contact licensed hazardous waste disposal companies for proper treatment and disposal. Small quantities may be neutralized carefully with appropriate bases under controlled conditions by qualified personnel, but professional disposal is recommended for most situations.

4-methylbenzenesulfonic acid is classified under ADR Class 8 (corrosive substances), Packing Group III for transportation purposes. This classification requires appropriate packaging, labeling, and documentation for road transport. Containers must meet UN specification requirements and display proper hazard labels. Transport vehicles need appropriate equipment for corrosive materials handling. Drivers require ADR training certification, and transport documents must include proper shipping names and emergency response information.

4-methylbenzenesulfonic acid is subject to REACH regulation requiring registration for manufacture or import above 1 tonne annually in the EU. The substance must be classified and labeled according to CLP regulation with GHS07 pictogram and warning signal word due to its irritating properties. It is not currently listed as a SVHC (Substance of Very High Concern). Users must comply with ADR transport regulations and maintain safety data sheets for workplace safety compliance.

4-methylbenzenesulfonic acid is available through OYSI, a specialized European distributor of technical chemicals serving industrial customers across the region. OYSI provides this substance with complete regulatory documentation including safety data sheets and certificates of analysis. As an established chemical distributor, OYSI ensures proper packaging, labeling compliance with European regulations, and reliable supply chains for professional users requiring this specialized organic acid for their industrial applications.