Quinoline yellow, dyestuff

Quinoline yellow (spirit sol.). Colour remains un- 1 changed Quino line Class 1 The dyestuff dissolves in 95 P r cent alcohol. Reduce the alcoholic solution with zino-dust, and acetic acid. The dyestufljis insoluble in caustic soda. Boll with 95 per cent alcohol. 

These dyestuffs include the cyanines, quinoline red, and probably quinoline yellow ( ). 

Owing to its high price quinoline yellow has only found a limited application. It gives very fast shades, and would be valuable in dyeing if the cost of production were less. It is applied solely as sulphonic acid and is dyed like the acid dyestuffs. The shades produced are pure yellow, free from any tinge of red. 

The reaction of chlorobenzene with phthalic anhydride to yield 2-chloro-anthraquinone, which is used as an intermediate in the production of indanthrone (see Chapter 11.3.2), was of great industrial importance for the early tar-based dyestuffs industry. Reaction of phthalic anhydride with quinaldine yields quino-phthalone, which is the basis of the quinoline yellow dyes. 

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