What it is
Red 227 is the Japanese colorant designation for Fast Acid Magenta (CI 17200; D&C Red No. 33; CAS 3567-66-6). Japan’s official specification identifies the disodium salt of an amino-hydroxy-phenylazo naphthalenedisulfonic acid, with molecular formula C₁₆H₁₁N₃Na₂O₇S₂. It describes a brown powder or granules that dissolve in water to produce a magenta-red solution. This is an azo dye, chemically distinct from the thioindigo pigments CI 73360 and CI 73385. The stated formula describes the disodium dye; an aluminium lake is a separately prepared pigment material and should not be assigned that same fixed composition.
Safety & warnings
Use restrictions and purity specifications depend on the jurisdiction and the particular dye or lake material. The previous discussion of a chlorinated CI 73385 pigment described another substance and has been removed. Consult the applicable colorant specification for the actual material used in a product.
Origin & sourcing
Fast Acid Magenta is made by chemical synthesis. Its azo chromophore contains a nitrogen–nitrogen linkage connecting aromatic groups; sulfonate groups and sodium counterions distinguish the water-soluble disodium dye from an insoluble lake pigment.
History
The Japanese official colorant specification lists Red 227 as Fast Acid Magenta. The same dye is identified by the Colour Index designation CI 17200 and the US name D&C Red No. 33. Regional naming systems use different numbers for the same dye, so “227” is not a Colour Index number.
Questions everyone asks
What is Red 227?
Red 227 is the Japanese designation for Fast Acid Magenta, also known as CI 17200, Acid Red 33 and D&C Red No. 33. It is a synthetic azo dye.
What is its molecular formula?
Japan’s specification gives C₁₆H₁₁N₃Na₂O₇S₂ for the disodium dye. That formula does not describe an aluminium lake or every commercial colorant preparation.
What color does Red 227 produce?
The official specification describes a brown powder or granules and a magenta-red aqueous solution. Powder appearance and solution color can differ.
Is Red 227 the same as Red 226?
They are different colorants. Red 227 is the azo dye CI 17200 (D&C Red No. 33); Red 226 is the thioindigo pigment CI 73360 (D&C Red No. 30).