Monoazo food colours :- (Part 2)
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Monoazo food colours:- (Part 2)
The method of preparation of the pyrazolone is already giben in the Chapter 6. Anothe mehtod followed for the synthesis of Trartrazone is to condense phenyl hydrozine-para-sulphonic acid with dihydroxy tartaric acid (1 mole) in aqueous phase and boil the solutiion to get tartrazidne. The dihydroxy tartaric acid reacts in the form of diketosuccinic acid which form bis-(phenyl hydrazone) which cyclises and rearranges to the dye. The details of its use as food colour is given in Chapted 8, the miscellaneous uses of dyestuffs.
