Orsellinic acid.CHAPTER 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.

Orsellinic acid, C₈H₈O₄, H₂O, was first prepared by Stenhouse (Annalen, 68, 61) by digesting lecanoric acid with boiling baryta water, and can also be produced from erythrin in a similar manner. According to Hesse (ibid., 139, 35), the solution of erythrin in baryta water is heated on the steam-bath until a sample of the product no longer yields a gelatinous precipitate when neutralised with hydrochloric acid. The liquid is then acidified, and the orsellinic acid, which separates on standing, is crystallised from alcohol or acetic acid.

Orsellinic acid crystallises from dilute acetic acid in needles with 1H₂O. When heated, it melts at 176° with evolution of carbon dioxide and formation of orcin, and is evidently an orcin carboxylic acid.

Ethyl orsellinate, C₁₀H₁₂O₄, colourless leaflets, melting-point 132°, is produced when erythrin is boiled for several hours with alcohol (Stenhouse, loc. cit.), and can be prepared in an identical manner from lecanoric acid (Schunck, Annalen, 54, 265).

Methyl orsellinate, C₉H₁₀O₄ (Schunck, loc. cit., and Stenhouse, loc. cit.), and isoamyl orsellinate, C₁₃H₁₈O₄ (Stenhouse; Hesse, Annalen, 139, 37), melting-point 76°, have also been obtained.

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