Tyrian purple by ancient authors. Not much is known about the subsequent steps, and the actual ancient method for mass-producing the two murex dyes has not yet been successfully reconstructed; this special "blackish clotted blood" colour, which was prized above all others, is believed to be achieved by double-dipping the cloth, once in the indigo dye of "H. trunculus" and once in the purple-red dye of "B. brandaris". The Roman mythographer Julius Pollux, writing in the 2nd century AD, asserted ("Onomasticon" I, 45–49) that the purple dye was first discovered by the philosopher Heracles of Tyre, or rather, by his dog, whose
Carbene dye dyed. For example, a dye that can colour cotton would usually not be appropriate for dyeing polyethylene, but by using a carbene, the same dye can be used for both. Carbene dye A carbene dye is a reactive dye based on carbene chemistry. A benzophenone is functionalised with a chromophore or group that can be easily converted to a chromophore at a later stage. The functionalised benzophenone is reacted with hydrazine hydrate and subsequently treatment with mercury oxide. The resulting diazo compound is stable at room temperature. On heating, nitrogen gas is released and the carbene generated. The thus generated