C.I.23655 Direct Orange 31 C.I. Direct Orange 31 Diaphtamine Fast Orange PRS C.I.Direct Orange 31:C.I.23655 5-[[4'-[[4,5-Dihydro-3-methyl-5-oxo-1-(4-sulfophenyl)-1H-pyrazol-4-yl]azo]-3,3'-dimethyl-1,1'-biphenyl-4-yl]azo]-2-hydroxybenzoic acid disodium salt