The Natural Organic Colouring Matters
By
Arthur George Perkin, F.R.S., F.R.S.E., F.I.C., professor of colour chemistry and dyeing in the University of Leeds
and
Arthur Ernest Everest, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; Late head of the Department of Coal-tar Colour Chemistry; Technical College, Huddersfield
Longmans, Green and Co.
39 Paternoster Row, London
Fourth Avenue & 30th Street, New York
Bombay, Calcutta, and Madras
1918
Kaikki kuvat (kemialliset kaavat) puuttuvat // None of the illustrations (of chemical formulas) included.
The purplish-brown petals of the common garden wallflower are comparatively rich in colouring matter, though the shade given by these on alumina mordant possesses a greenish-olive-yellow tint, and is of a less pure character than that given by the variety known as "Cloth of Gold". A boiling aqueous extract of these latter flowers on treatment with sulphuric acid gradually deposits a yellow precipitate, and this is most readily purified by pouring the concentrated alcoholic solution into much ether. The main impurity is thus precipitated, whereas the colouring matter remains dissolved in the ether. By fractional crystallisation from alcohol two colouring matters can be isolated from this product, (a) sparingly soluble which consists of isorhamnetin (quercetin monomethyl ether) and (b) quercetin. The existence of isorhamnetin was first demonstrated by an examination of these flowers (Perkin and Hummel, Chem. Soc. Trans., 1896, 69, 1566).
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