Synthesis And Dyeing Properties Of The Cationic Reactive Dyes

The reactive dye is one kind of chemically-reactive dye which could react with fiber via covalent bond.But it is necessary to use a large amount of salt when dyeing cellulose fiber in the traditional dyeing process.This often causes environmental pollution,leading water pollution and ecological environment problems.Therefore,developing environment-friendly reactive dyes dyeing with less salt or no salt has attracted significant attentions in recent years.The cationic reactive dyes containing a quaternary ammonium salt group could dye the cotton fabric without any salts.The cations are mainly aromatic and aliphatic quaternary ammoniums.The chemical structures of these dyes mainly based on azo,anthraquinone and heterocycle.In this paper,1-aminoanthraquinone and 1,4-diaminoanthraquinone are used as the raw materials to synthesize two cationic reactive dyes,using two different routes respectively.(1) One yellow cationic reactive dye based on 1-aminoanthraquinone was synthesized following below steps.The first step was an acetylation of 1-aminoanthraquinone group using cyanuric chloride.After that,N,N-Dimethyl-1,3- propylene diamine was introduced into structure via a nucleophilic substitution reaction.Finally,the tertiary amino group was reacted with Diethyl Sulphate to form a quaternary salt.(2) One purple cationic reactive dye based on 1,4-diaminoanthraquinone was synthesized following below steps.Firstly,1,4-diaminoanthraquinone was combined with cyanuric chloride. Then,the pyridine quaternary ammonium salt was introduced into the intermediate directly.The structures of two synthetic dyes were characterized by using FT-IR and ~1H-NMR analysis.Differential scanning calorimetry(DSC) and thermal gravimetric analysis(TGA) were employed to study the melting point and thermal stability.The results indicated that both of the dyes had high thermal stability under 200℃.Their hydrolytic stability was investigated by UV-vis absorbances of the dye solutions with different pH values at the same temperature.The study showed that the stability time of two dye solutions increased with the decrease of pH value.In addition,1,4-diaminoanthraquinone cationic reactive dye incorporating pyridine cation had a higher hydrolytic stability comparing with 1-aminoanthraquinone cationic reactive dye incorporatiing aliphatic cation.The two cationic dyes were employed in dyeing cotton,wool and nylon fabric respectively. The effect of dyeing conditions including pH value,temperature,time,concentration and salt on extent of exhaustion,extent of fixation,fixation efficiency and K/S values were discussed in details.The proper dyeing conditions were chosen to dye these fabrics,and the washing and rubbing fastness of dyeing samples were also tested.It was found that the cationic dyes applied to cotton fabric had high extent of exhaustion and fixation.Also,the dyes enjoyed good dyeing properties after the dyeing process of wool and nylon fabric.