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.
Sophora japonica (Linn.). This is a large and beautiful tree, not unlike an acacia, belonging to the Leguminosæ, which grows abundantly throughout China.
The undeveloped flower-buds constitute an important yellow dyestuff employed by the Chinese for colouring the silken vestments of the mandarins. For this purpose the buds are collected and dried rapidly, either in the sun or by artificial means, usually with the addition of a little chalk. The method of dyeing consists in simply boiling for one to one and a half hours in a decoction of the flower-buds silk which has been previously mordanted by steeping overnight in a.decoction of alum. Less frequently it is employed in the dyeing of cotton and wool. Its price appears to be about 305. a cwt.
This dyestuff has been studied by many chemists, especially by Schunck (Chem. Soc. Trans., 1888, 53, 262; 1895, 67, 30), who has proved that the glucoside which it contains, formerly called sophorin (Forster, Ber., 1882, 15, 214), is in reality identical with rutin, the quercetin glucoside first isolated from rue (Ruta graveolens, Linn.) by Weiss (Chem. Zentr., 1842, 903). (Cf. also Stein, J. pr. Chem., (i.), 58, 399; 85, 351; 88, 280; Schunck, Manchester Memoirs, 1858, 2 Ser., 15, 122.) The glucoside is readily isolated by extracting the flower buds with boiling water. The liquid on cooling deposits crystals of rutin, which can be purified by recrystallisation from water or dilute alcohol.
When applied to wool the Sophora japonica buds give colours somewhat like those obtained with quercitron bark, viz. a dull orange with chromium, a yellow of moderate brilliancy with aluminium, a bright yellow with tin, and a dark olive with iron. In dyeing power it seems to be equal if not slightly superior to quercitron bark, and is to be regarded as an excellent natural dyestuff, quite equal to those of similar character in general use (Hummel and Perkin, J. Soc. Chem. Ind., 1895, 458).
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