ErythrinCHAPTER XVI. Lichens, Lichen acids, and Colouring Matters Derived Therefrom.(Osa artikkelista)

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.

Erythrin, erythric acid, erythrinic acid, erythroiecanoric acid, C₂₀H₂₂O₁₀H₂O, is a constituent of most lichens from which archil is prepared. It was discovered by Heeren (Schweigger's Journ. f. Chem., 59, 513) in Rocella tinctoria (D.C.), from which lichen, and several others of the same genus, it may be extracted by boiling water, or better, with milk of lime (cf. also Kane, Stenhouse, and Hesse (loc. cit.); Schunck, Annalen, 61, 69; De Luynes, Ann. Chim. Phys., [4], 2, 385; Menschutkin, Bull. Soc. chim., [2], 2, 424).

The method adopted by Stenhouse to prepare this substance from the Rocella fuciformis is as follows (Annalen, 68, 72, and 149, 290): Three pounds of the lichen are macerated for twenty minutes in a milk of lime made by shaking ½ lb. of lime in 3 gallons of water, and the product filtered by means of a bag filter. The clear liquid, as it passes through, is immediately precipitated with hydrochloric acid, as prolonged contact with the lime decomposes part of the erythrin. The crude erythrin collected on bag filters is freed from acid and calcium chloride by stirring it up once or twice with a considerable quantity of water and again collecting.

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