植物靛蓝与合成靛蓝染料的还原性比较

Comparison of the reducibility of plant indigo and synthetic indigo dyes

为了比较植物靛蓝和合成靛蓝染料的性能差异,选择还原温度、氢氧化钠或碳酸钠用量、还原时间及保险粉用量等因素,在多水平条件下进行靛蓝染料还原实验。结果表明:植物靛蓝和合成靛蓝染料在还原条件上有很大差异,合成靛蓝染料需要在高温、强碱、高浓度、强还原剂条件下还原,在还原温度≥80℃、烧碱质量浓度5~8 g/L、保险粉质量浓度≥20 g/L条件下染液的还原效果较优;植物靛蓝染料仅需要在低温、弱碱、较低质量浓度还原剂的条件下还原,即40℃、纯碱质量浓度11 g/L、保险粉质量浓度16 g/L。二者在还原条件上的差异是区分植物靛蓝与合成靛蓝染料的手段之一。

Being vat dyes, indigo dyes will go through an oxidation-reduction process when dyeing for fibers. In order to compare the performance differences between plant indigo and synthetic indigo dyes, the reduction experiments of indigo dyes were carried out under different conditions by choosing the reduction temperature, the amount of sodium hydroxide or sodium carbonate, the reduction time and the amount of insurance powder. The experimental results showed that there were great differences in the reduction conditions between plant indigo and synthetic indigo. The synthetic indigo needed to be reduced under the conditions of high temperature, strong alkali and high concentration of strong reductant, such as reduction temperature(≥80 ℃), 5-8 g/L caustic soda and(≥20 g/L) of insurance powder concentration. The reduction effect of dye solution was better at this time. Plant indigo only needed low temperature, weak alkali and low concentration reductant, and was pure at 40 ℃, 11 g/L caustic soda and 16 g/L powder concentration. The difference between the two conditions was one of the ways to identify plant indigo and synthetic indigo.