Exporter and Supplier of Meta Phenylene Diamine 4 Sulphonic Acid . We have been Supplying Meta Phenylene Diamine 4 Sulphonic Acid since so many years to our customers . The Molecular formula is C6H8N203S .The CAS number is 3177-22-8 .The Molecular weight is 188. The Purity is 75 % minimum . It is brownish powder form . It is only 20% soluble in water or can say it is insoluble in water fully . The iron Content is 200 ppm max.