NarrawoodCHAPTER XVIII. Colouring Matters of Unknown Constitution. The Insoluble Red Woods

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.

Narrawood, Pterocarpus spp., a well-known Philippine wood, according to Brooks (Philippine Journal of Science, 1910, v., 448), contains constituents very similar to those of sanderswood. To isolate the red colouring matter, the wood shavings were extracted with alcohol, the alcoholic extract concentrated and three volumes of water added. The solution was boiled to remove alcohol, and the red amorphous mass, which had then separated, was digested with about five parts of chloroform.

Thus obtained, Narrin consisted of a dark red amorphous powder, readily soluble in alcohol and insoluble in chloroform, which could not be obtained in a crystalline state. According to Brooks it is not identical with the santalin of sanderswood, for a preparation of this melted at 104°, whereas narrin does not melt but swells with charring about 180°. When fused with alkali narrin gives phloroglucinol and resorcinol, and by a slow oxidation with permanganate 12 grams gave 0,5 gram of a substance possessing a strong odour of vanillin. That it consisted of this substance was confirmed by its conversion into the phenylhydrazone which melted at 104. By distillation with zinc-dust narrin yields a small amount of resorcinol dimethyl ether. Narrin, like santalin, gives with alcoholic potassium acetate a precipitate of potassium salt, and the copper salt prepared in this way with copper acetate had the composition (C₁₅H₁₃C₅)₂Cu.

The dyeing properties of narrin are similar to those of santalin, but the shades produced are not very fast to soap.

In addition to colouring matter, Brooks isolated from narrawood both ptero-carpin and homoptero-carpin. By a careful examination of these substances he concluded that the formulæ previously assigned to them is incorrect, and should in reality be, respectively, C₁₄H₁₂O₄ and C₁₇H₁₅JO₄ (see "Sanderswood ").