Cotoïn. (Osa artikkelista)(CHAPTER III. The Benzophenone Group.)

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.

Cotoïn can be isolated from true Coto bark by extracting the powdered bark with cold ether, distilling off the ether from the extract, and mixing the residue, whilst still hot, with light petroleum, whereupon a resinous-oily mass separates, from which the solution of cotoïn can be decanted and the product obtained from it in the form of large yellow crystals. A further quantity can be obtained from the resinous mass mentioned above by boiling it with lime-water, and treating the solution obtained with hydrochloric acid, when the cotoïn is precipitated. Cotoïn may be recrystallised from alcohol, or hot water, when it separates in yellow prisms, melting-point 130-131°C. It is difficultly soluble in cold water, readily soluble in hot, is fairly soluble in alcohol, ether, and chloroform, but sparingly soluble in light petroleum or benzene. It dissolves in alkalis forming yellow solutions from which it is reprecipitated on acidification. As decomposition products of cotoïn, phloroglucinol as also benzoic acid have been obtained.

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A number of poly-hydroxy benzophenone derivatives, including products found in Coto bark and related to cotoïn, have been prepared by W. H. Perkin and Robinson (Proc. Chem. Soc., 1906, 305).