Fuel dyes are dyes added to fuels, as in some countries it is required by law to dye a low-tax fuel to deter its use in applications intended for higher-taxed ones. Untaxed fuels are referred to as "dyed", while taxed ones are called "clear" or "white".
The dyes used have to be soluble in hydrocarbon-based nonpolar solvents ("solvent dyes"), and therefore in the fuels they are added to. Red dyes are often various diazo dyes, eg. Solvent Red 19, S...
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Fuel dyes are dyes added to fuels, as in some countries it is required by law to dye a low-tax fuel to deter its use in applications intended for higher-taxed ones. Untaxed fuels are referred to as "dyed", while taxed ones are called "clear" or "white".
The dyes used have to be soluble in hydrocarbon-based nonpolar solvents ("solvent dyes"), and therefore in the fuels they are added to. Red dyes are often various diazo dyes, eg. Solvent Red 19, Solvent Red 24, and Solvent Red 26. Anthraquinone dyes are used for green and blue shades, eg. Solvent Green 33, Solvent Blue 35 and Solvent Blue 26.
Due to technological requirements, it is advantageous to mix a liquid with a liquid instead of handling powdered dyes. The pure dyes are solid crystalline materials, therefore they have to be highly soluble, so concentrated solutions can be used instead.
Aviation gasoline is dyed, both for tax reasons (avgas is typically taxed to support aviation infrastructure) as well as safety -- there being...
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