Starting Materials: The process begins with petroleum-derived chemicals, often including p-cresidin, a white crystalline solid.
Diazotization: The p-cresidin is converted into a diazonium salt through a chemical reaction.
Coupling Reaction: The diazonium salt is then combined with a coupling component, typically 2-naphthol-6-sulfonic acid. This coupling reaction forms an azo compound, which is the key component responsible for the red color.
Purification and Processing: The resulting azo compound is purified and processed to obtain the final Red Dye No. 40 product. This involves steps like filtration, drying, and milling to achieve a fine powder form.
It’s important to note that the production of Red Dye No. 40 is a complex industrial process that requires specialized equipment and expertise.
What is in Red Dye No. 40?
Red Dye No. 40, also known as Allura Red AC, is a synthetic food dye made from petroleum. 1 It’s a naphthalene sulfonic acid, a type of chemical compound. 2 The dye is typically found in a dark red powder or small granule form. 3 It’s soluble in water, 50% alcohol solutions, glycerol, and propylene glycol. 4