Sudan II

Sudan II (C18H16N2O) is a lysochrome (fat-soluble dye) azo dye used for staining of triglycerides in frozen sections, and some protein bound lipids and lipoproteins on paraffin sections. It has the appearance of red powder with melting point 156-158 °C and maximum absorption at 493(420) nm.

Its other names are Solvent Orange 7, C.I. Solvent Orange 7, and C.I. 12410. It is also known as: A.F. red No. 5, Aizen food red No. 5, Brasilazina oil scarlet 6G, Brilliant oil scarlet B, Calco oil scarlet BL, Ceres Orange RR, Cerisol scarlet G, Cerotinscharlach G, Ext. D and C red No. 14, Extract D and C red No. 14, Fast oil Orange II, Fat scarlet 2G, FD and C red 32, FettOrange B, Grasan Orange 3R, Lacquer Orange VR, Motirot G, Oil Orange KB, Oil red GRO, Orange oil KB, Orange RR, Ponceau à l'huile, Pyronalrot R, Red B, Red No. 5, Resin scarlet 2R, Resoform Orange R, Rot B, Somalia Orange 2R, Soudan II, Sudan AX, Sudan Orange, Sudan red, Sudan scarlet 6G, Sudan X, Waxakol vermilion L.

In industry, it is used to color nonpolar substances like oils, fats, waxes, greases, various hydrocarbon products, and acrylic emulsions.