Solvent Yellow 7
Solvent Yellow 7 is an aromatic organic molecule and a common azo dye with a formula of C6H5N2C6H4OH. It has a phenolic hydroxyl and an azo group in the same molecule.
Synthesis
Like most azobenzenes, Solvent Yellow 7 can be synthesized by the reaction of the phenyldiazonium salt with phenol. The optimal pH value for this azo coupling is 8.5-10. The reaction is carried out in water, since sodium chloride formed in the reaction is soluble in water, while the product precipitates.[Image:Azo-coupling-A-mechanism-2D-skeletal.png|center|800px]
As azo dyes are not usually water soluble, the effect of various solvents on them has been studied analytically, and likewise analytical methods and calculations for the color concentration developed.