Rubian was an uncrystallisable gum, hydrolysable by acids or an enzyme contained in the madder root to give alizarin and a sugar.
32.
William Perkin, the inventor of mauve, filed a patent in June 1869 for a new way to produce alizarin without bromine.
33.
The plant's roots contain an anthracene compound called alizarin that gives its red colour to a textile dye known as Rose madder.
34.
The synthetic alizarin could be produced for a fraction of the cost of the natural product, and the market for madder collapsed virtually overnight.
35.
He found that oxidation of alizarin with nitric acid gave alizaric acid ( phthalic acid ) which on heating gave pyroalizaric acid ( phthalic anhydride ).
36.
Purpurin is only present in the natural form of madder and gives a distinctive orange / red generally warmer tone that pure synthetic alizarin does not.
37.
After Leverkus'death in 1891 his sons sold a portion of the factory site in Wiesdorf to the alizarin manufacturer " Elberfelder Farbenfabriken vorm.
38.
Rubian was actually a mixture of glycosides of di and trihydroxy anthraquinones of which a major component was ruberythric acid which is an alizarin 2 b primeveroside.
39.
These works, rendered in a variety of reds, from subtle orange to deep Alizarin and brown Madders are drawn from the subjects of mythology and drama.
40.
This led to the suggestion that alizarin was a derivative of naphthalene, a C10 hydrocarbon, although Schunck pointed out that this did not explain the reactions of alizarin.
