CAS Number: 39616-92-7
Molecular Formula: C12H9NaO5S2
Molecular Weight: 320.31663
EINECS Number: 254-543-5 

Diphenylsulfone-3-sulfonic acid sodium salt (CAS number: 39616-93-8) is an organic compound containing sulfonic acid groups. Its applications are mainly based on the water solubility and reactivity of the sulfonic acid groups, and specific applications include: 
1. Dyes and Pharmaceutical Intermediates
As a sulfonation reaction intermediate, it is used for synthesizing phenolic and nitrile compounds as well as dyes.
In the pharmaceutical field, it may be used to prepare sulfonamide drugs or other active ingredients containing sulfonic acid groups. 
2. ‌Surfactants and Additives‌
The sulfonic acid groups give it good water solubility and can be used as emulsifiers, penetrants or dispersants. Similar to sodium dodecyl sulfonate, it is applied in the textile and dyeing industries. 
3. ‌Flame Retardant Auxiliary Components ‌
Sulfonate compounds are often combined with bromine/phosphorus flame retardants to quench the combustion chain reaction and enhance the flame retardancy of materials, especially in engineering plastics such as polycarbonate (PC).