History
The Monstral blue found to coat the inside of copper vessels used to process phthalic acid derivatives had lead to the discovery of Phthalocyanine in 1907. Attracted by the brilliance, stability and insolubility of this chromophore, attempts were made to reversibly modify it so that it would be carried into fabric in a solution and then easily precipitated (ingrained) into an unleachable but finely well dispersed deposit (hence the name "ingrain dyeing"). From this attempt, Alcian Blue (Ingrain blue 1) was first synthesized by the ICI dyestuffs department under N. H. Haddock and Wood in the early 1940s and patented in 1947 (Patent numbers: GB 586340 and GB 587636), originally as a textile dye. In 1950 it was used by Steedman as a selective dye for mucins. While the popularity of Alcian blue expanded exponentially, the difficulty involved in its production due to environmentally hazardous intermediate steps made its availability difficult and ICI stopped producing it by 1973. Many of the alternate sources sold similar looking color products with unreliable staining.
Prof J.E. Scott worked to decipher the chemistry of Alcian blue which was known only to the Industry but kept as a tight trade secret. After spending 3 man-years of effort (which would have been unnecessary had the industry released the results)in 1972 he published the structure of Alcian blue and was able to get ICI to confirm it in 1973, incidentally in the same time that ICI also had just stopped producing it.
After the interim crisis since 1970s when ICI had to stop, there have now been environmentally safe alternative industrial manufacturing of this dye that is supposed to work as well as 8GX but is called 8G since it is made differently. In attempt to answer what was the importance of discovering an alternative method of manufacturing this compound, a company (Anatech Ltd, USA) which remanufactured Alcian Blue says:
- "Alcian blue is highly selective for the tissue substances (given the proper solution pH), and forms insoluble complexes that withstand harsh subsequent treatment (like PAS) without destaining. That is what makes this dye so important. Do any other dyes have this attribute? Yes, two others to be exact, out of thousands listed in the Colour Index and Conn's Biological Stains." These two are 'Alcian yellow' and basic red 18 which are again both equally unavailable and also lack the brilliant contrast of the blue.
Read more about this topic: Alcian Blue Stain
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