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Molecular Weight null
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MDL number MFCD03100366
Quercitron is a yellow natural dye obtained from the bark of the Eastern Black Oak (Quercus velutina), a forest tree indigenous in North America. The name is a shortened form of quercicitron, from Latin quercus,
oak, and citron, lemon,
and was invented by Edward Bancroft (1744–1821), who by act of parliament in 1785
was granted special privileges in regard to the importation and use of the
substance.
Detailed
description
. The dyestuff is prepared by
grinding the bark in mills after it has been
freed from its black epidermal layer, and sifting the product to separate the fibrous matter, the fine yellow powder which remains forming the quercitron of
commerce. The ruddy-orange decoction of quercitron
contains quercitannic acid, whence its use in tanning, and an active
dyeing principle, quercitrin, C21H20O11.
The latter substance is a glycoside, and in aqueous
solution under the influence of mineral acids it yields quercetin, C15H10O7,
which is precipitated, and the methyl-pentoserhamnose.[1]
Quercetin is a crystalline powder of a brilliant
citron yellow color, entirely insoluble in cold water and dissolving only
sparingly in hot water, but quite soluble in alcohol. Either by itself or in
some form of its glucoside quercitrin, quercetin is found in several vegetable
substances, among others in cutch, in Persian berries (Rhamnus cathartica), buckwheat leaves (Fagopyrum
esculentum), Zante
fustic wood (Rhus
cotinus), and in rose petals.[1]
Chemically, quercetin is a member of a fairly
extensive class of natural coloring matters derived from phenyl benzoyl-pyrone
or flavone, the constitution of which followed on the
researches of St von Kostanecki, A. G. Perkin, Herzig, Goldschmidt and others.
Among the related, coloring matters are: chrysin from poplar buds, apigenin from parsley, luteolin from weld, mignonette and dyer's broom, fisetin from
young fustic and yellow cypress, galangin from galangal root, and myricetin from Nageia nagi.
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