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QUERCITRON

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Originally appearing in Volume V22, Page 742 of the 1911 Encyclopedia Britannica.
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QUERCITRON , a yellow dyestuff obtained from the bark of the quercitron See also:

oak, Quercus tinctoria, a See also:fine See also:forest See also:tree indigenous in See also:North See also:America. The name is a shortened See also:form of " quercicitron," from See also:Lat. quercus, oak, and " citron," and was invented by Dr See also:Edward See also:Bancroft (1744-1821), who by See also:act of See also:parliament in 1785 was granted See also:special privileges in regard to the importation and use of the substance. The dyestuff is prepared by grinding the bark in See also:mills after it has been freed from its See also:black epidermal layer, and sifting the product to See also:separate the fibrous See also:matter, the fine yellow See also:powder which remains forming the quercitron of See also:commerce. The ruddy-See also:orange decoction of quercitron contains quercitannic See also:acid, whence its use in tanning, and an active See also:dyeing principle, quercitrin, C21H220,2. The latter substance is a See also:glucoside, and in aqueous See also:solution under the See also:influence of See also:mineral acids it yields quercetin, C16H6007, which is precipitated, and the pentoside rhamnose. Quercetin is a crystalline powder of a brilliant citron yellow See also:colour, entirely insoluble in See also:cold and dissolving only sparingly in hot See also:water, but quite soluble in See also:alcohol. Either by itself or in some form of its glucoside quercitrin, quercetin is found in several See also:vegetable substances, among others in See also:cutch, in See also:Persian berries (Rhamnus catlaarticus), See also:buckwheat leaves (Polygonum Fagopyrum), See also:Zante See also:fustic See also:wood (Rhus Cotinus), and in See also:rose petals, &c. Quercitron was first introduced as a yellow dye in 1775, but it is. principally used in the form of See also:flavin, which is the precipitate thrown down from a boiling decoction of quercitron by sulphuric acid. Chemically, quercetin is a member of a fairly extensive class of natural colouring matters derived from 13 phenyl benzo-y-pyrone or flavone, the constitution of which followed on the researches of St von Kostanecki, A. G. See also:Perkin, Herzig, See also:Goldschmidt and others. Among the related colouring matters are: chrysin from See also:poplar buds, apigenin from See also:parsley, luteolin from weld and dyers' See also:broom, fisetin from See also:young fustic and yellow See also:cedar, galangin from galanga See also:root, and myricetin from Myrica Nagi.

End of Article: QUERCITRON

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QUERCY (Lat. pagus Caturcinus, Fr. Cahorsin)

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