Tyrian purple to be 6,6′-dibromoindigo, derivative of indigo dye that had previously been synthesized in 1903. However, it has never been synthesized commercially. In 1998, through a lengthy trial and error process, an English engineer named John Edmonds rediscovered a process for dyeing with Tyrian purple. He researched recipes and observations of dyers from the 15th century to the 18th century. He explored the biotechnology process behind woad fermentation. After collaborating with a chemist, Edmonds hypothesized that an alkaline fermenting vat was necessary. He studied an incomplete ancient recipe for Tyrian purple recorded by Pliny the Elder. By altering the percentage of
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