Dermorubin and 5-Chlorodermorubin Natural Anthraquinone Carboxylic Acids as Dyes for Wool

Wool is dyed for the first time with a mixture of two pure natural anthraquinone carboxylic acids, dermorubin and 5-chlorodermorubin (2:1), by means of the acid dyeing technique. The anthraquinone carboxylic acids are isolated from the fungus Dermocybe sanguinea and separated by multiplicative liquid-liquid partition using a stepwise pH gradient. The color of the dyed wool is investigated in terms of the CIELAB L*, a*, and b* parameters, and color-fastnesses to light, washing, and rubbing are tested according to ISO standards. The mixture of dermorubin and 5-chlorodermorubin dyes wool orange-red with good color-fastness properties. Our procedure is equivalent to the industrial winch- technique. The results indicate that wool has a high uptake for the anthraquinone carboxylic acids. Apparently, the ionic bonds between the carboxylate ions of the dye and the protonated amino groups of the wool enhance the color-fastness properties of the dyed fabric. Dermorubin and 5-chlorodermorubin have significant potential as textile dyes. affording useful alternatives to synthetic dyes.