Solvent Red 164

  Solvent Red 164, also called Oil Red B, is a synthetic red diazo dye. Its chemical structure is 1-[[4-[phenylazo]-phenyl]azo]-2-naphthol. The inventors of the product were Morton International under the commercial name Automate Red B.

Additional recommended knowledge

What is the Sensitivity of my Balance?

Weighing the right way

Daily Visual Balance Check

Its main use is as a fuel dye in the United States of America mandated by the IRS to distinguish low-taxed heating oil from automotive diesel fuel, and by the EPA to mark fuels with higher sulfur content; it is a replacement for Solvent Red 26 with better solubility in hydrocarbons. [1] The concentration required by IRS is a spectral equivalent of 3.9 pounds per 1000 barrels, or 11.13 mg/l, of Solvent Red 26 in solid form; the concentrations required by EPA are roughly 5 times lower.

It is also used to dye some hydraulic fluids and some other hydrocarbons, predominantly gasoline.

Its CAS number is [92257-31-3] and its SMILES structure is Oc2ccc1ccccc1c2 N=Nc3ccc(N=Nc4ccccc4)cc3.