preparation??and?C.I. .Solvent Red 42?and similar (2,4-Dichlororesorcinol?(2 Moore) and?Phthalic anhydride?(1 Moore) with Sodium hydroxide extraction condensation, segregation out 2 ‘, 4 ‘, 5 ‘, 7 ‘- tetrachloro-fluorescein, then use hydrochloric acid acidification.
Properties and Applications
brilliant orange. Insoluble in water, slightly soluble in alcohol, soluble in 5% sodium carbonate solution. In concentrated sulfuric acid to yellow, dilution have orange precipitation; In 10% sodium hydroxide solution for pink.
