C、I、分散蓝79在高温染色时的还原副反应及Cu^(++)、Fe^(++)的催化作用

THE REDUCING SIDE-REACTION OF C. I. DISPERSE BLUE 79 DURING HIGH-TEMPERATURE DYEING PROCESS AND THE CATALYSIS OF Cu^(++), Fe^(++) IONS

本文应用红外、质谱分析和合成结构对照,确定了C、I、分散蓝79以木质素磺酸钠为分散剂在高温高压染色条件下所产生的副染料的化学结构。同时,采用柱层析分离各副染料,确定了不同Cu^(++)、Fe^(++)离子浓度下各副染料的转化率。初步探讨了Cu^(++)、Fe^(++)离子对染料的催化还原作用。实验发现,染料的脱溴还原,硝基还原成亚硝基和偶氮键的还原断裂是染料在染色过程中的主要副反应;Cu^(++)、Fe^(++)离子浓度对染料的总还原率和各副染料的转化率均具有很大的影响。因此,在选用象C、I、分散蓝79这样的染料时,选择低还原性的木质素磺酸钠和控制Cu^(++)、Fe^(++)离子浓度(<0.0313mol/kg木质素)对获得良好的染色效果是至关重要的。

In this paper, the chemical structure of by-products of C. I. disperse Blue 79 produced during the high—temperature dyeing process is confirmed by analyses of their infrared and mass spectra and the comparision of syntheic structure, when sodium lignin sulfonate is used as a dispersing agent. After separating all the by—products with the aid of column chromatography, the yield of these by—products at different Cu^(++), Fe^(++)ion concetrations are also determined. The effect of Cu^(++), Fe^(++)ions on the catalytic reduction of the given dye is discussed primarily. It is found that debrominative reduction, nitro group reduction (to form nitroso group) and reductive cleavage of azo bond are the main secondary reactions and that Cu^(++), Fe^(++)ion concentrations have great effect on total reduction rate and yields of by—products. Therefore, when we make a choice of dyes such as C. I. Disperse Blue 79, it is necessary to select a kind of sodium lignin sulfonate with low reduction potential and to control Cu^(++), Fe ion concentrations (0.0313 mol / kg sodium lignin sulfonate) for obtaining fine dyeing results.