The supercritical carbon dioxide (SC-CO₂) dyeing technology is a green dyeing technology, and the usage of natural dye makes SC-CO₂ dyeing technology safer and more environment-friendly. Nevertheless, after using natural dye in SC-CO₂ dyeing, the color depth and fastness of dyed natural fabric are poor. In this study, alkyl and hydroxyalkyl groups were grafted onto alizarin, which is a natural dye, to elevate the color depths and fastness of alizarin-derivative-dyed natural fabric. The results demonstrate that the color depths of alkyl-alizarin-dyed and hydroxyalkyl-alizarin-dyed natural fabrics were increased. This has to do with the increase in the solubilities of alkyl alizarin and hydroxyalkyl alizarin in SC-CO₂. The hydroxybutyl-alizarin-dyed wool displayed the best color depth (K/S value: 6.44). And the hydroxyalkyl-alizarin-dyed natural fabric showed good washing fastness and rubbing fastness (about 4–5 level), because that hydroxyalkyl alizarin could be linked by a covalent bond to the natural fabric.

超临界二氧化碳（SC-CO ₂）染色技术是一种绿色染色技术，天然染料的使用使SC-CO ₂染色技术更安全，更环保。然而，在SC-CO ₂染色中使用天然染料后，染色的天然织物的色深和牢度均较差。在这项研究中，将烷基和羟烷基基团接枝到天然染料茜素上，以提高茜素衍生物染色的天然织物的色深和牢度。结果表明，烷基-茜素染色和羟烷基-茜素染色的天然织物的色深增加。这与烷基茜素和羟烷基茜素在SC-CO ₂中的溶解度增加有关。羟丁基-茜素染色的羊毛显示出最佳的色深（K / S值：6.44）。羟烷基-茜素染色的天然织物显示出良好的耐洗牢度和耐摩擦性（约4-5级），因为羟烷基茜素可以通过共价键连接到天然织物上。