COLOR CONSTITUTION RELATIONSHIPS IN 2-ACYLAMINO-4-N,N-DIETHYLAMINOAZOBENZENE DISPERSE DYES

Nitration of N,N-diethylaniline in concentrated sulphuric acid afforde d a readily separable mixture of the 3- and 4-nitro derivatives, the f ormer being the major product. Reduction and subsequent reaction of 3- amino-N,N-diethylaniline with acid chlorides, chloroformates, isocyana tes and sulphonylchlorides gave a range of coupling components suitabl e for the synthesis of blue azo disperse, using 2-bromo-4-nitro-6-cyan oaniline as diazo component. The colour of the dyes is discussed with respect to electronic and steric effects in the acylamino (and analogo us) substituents; depending on the acylamino substituent, positive or negative solvalochromic effects were apparent in ethanol with respect to benzene and/or cyclohexane.