3-nitrobenzenesulfonic acid

3-Nitrobenzenesulfonic acid (CAS 98-47-5), also known as m-nitrobenzenesulfonic acid, is an aromatic sulfonic acid used primarily as a chemical intermediate and acid catalyst in organic synthesis. Its combination of a strong acid group and a nitro substituent makes it a selective building block for producing more complex molecules across several manufacturing sectors.

In pharmaceutical manufacturing, it serves as a key intermediate in the synthesis of active pharmaceutical ingredients and fine chemicals, where controlled nitro group chemistry is required. Dye and pigment producers use it as a coupling component or intermediate in the preparation of azo dyes applied to textile and leather substrates during the manufacturing process.

In textile processing, it functions as a dyeing auxiliary and pH modifier, improving dye uptake and fixation on fiber. Printing ink formulators also source it as a precursor for specialty colorants. 3-Nitrobenzenesulfonic acid is available commercially as a crystalline solid, typically supplied in powder or granule form. Standard supply concentrations include the anhydrous form and sodium salt derivatives.

Technical and pharmaceutical-intermediate grades are the most commonly traded. Packaging ranges from small laboratory quantities to bulk industrial lots depending on specific application requirements.