5-[[4'-[(6-Amino-1-hydroxy-3-sulfo-2-naphtyl)azo]-1,1'-biphenyl-4-yl]azo]-2-hydroxybenzoic acid disodium salt C.I.22306 C.I.Direct Red 33 Benzoic acid, 5-((4'-((6-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo)(1,1'-biphenyl)-4-yl)azo)-2-hydroxy-, disodium salt C.I.Direct Red 33:C.I.22306 Direct Red 33