1,5-Dichloroanthraquinone → 1,5-Bis(4-cyclohexylphenylamino)-anthraquinone

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Reaction Steps

In a round bottom flask equipped with stirrer, thermometer, and nitrogen inlet is added 2.77 g (0.1M) 1,5-bischloroanthraquinone and 3.5 g (0.2M) of 4-cyclohexylaniline. 3.0 g anhydrous sodium acetate and 0.1 g anhydrous copper acetate are added as acid acceptor and reaction catalyst respectively. 50 g nitrobenzene are added and the stirred mass is heated to reflux under nitrogen atmosphere. The reaction is allowed to proceed for two hours at 185° C. Upon cooling, 50 g methanol is added and the crude dye separated by vacuum filtration. Subsequent purification by recrystalization and chromatography from alumina using toluene as the elvent affords the magneta pleochroic dye 1,5-bis(4-cyclohexylphenylamino)-anthraquinone. The optical order parameter was measured as 0.7.

Provenance & Evidence