Dyestuffs of the formula: ##STR1## in which R.sub.2 and R.sub.4 which are the same or different each represent a hydrogen atom or an alkyl, hydroxyalkyl or cyanethyl group, one of the substituents R.sub.1 and R.sub.3 represents the 2,2,2-trifluoroethyl group and the other substituent represents an alkyl group or the 2,2,2-trifluoroethyl group, the ring A is unsubstituted by or substituted by one or 2 chlorine atoms or an alkoxy or alkyl group, the rings B.sub.1 and B.sub.2 are each unsubstituted or substituted by at least one alkyl or alkoxy group and X represents a colorless monovalent anion; process for the preparation of such dyestuffs; process for the coloration with such dyestuffs based on a polymer or copolymer of acrylic nitrile or on polyamides or polyesters which have been modified by anionic groups; and fibres based on a polymer or copolymer of acrylic nitrile or on polyamides or polyesters which have been modified by anionic groups colored by means of such dyestuffs.
化学式为:##STR1## 其中R.sub.2和R.sub.4相同或不同,分别代表氢原子或烷基,羟基烷基或
氰乙基基团,取代基R.sub.1和R.sub.3中的一个代表
2,2,2-三氟乙基基团,另一个代表烷基或
2,2,2-三氟乙基基团,环A未取代或取代一个或两个
氯原子或烷氧基或烷基,环B.sub.1和B.sub.2未取代或取代至少一个烷基或烷氧基,X代表无色单价阴离子;制备此类
染料的方法;基于
丙烯腈聚合物或共聚物或经阴离子基团改性的聚酰胺或聚酯的染色方法;以及基于
丙烯腈聚合物或共聚物或经阴离子基团改性的聚酰胺或聚酯的纤维,通过此类
染料染色。