USE MADE OF QUERCITRON.

401

The formula Ci 5 H io 06 is also given by Dr. Stenhouse to datiscetin, a bodyextracted by him from Datisca cannabina. It appears that the properties ofthis latter body and of paradatiscetin agree so closely as to allow the conclu-sion that these substances are identical. When the reaction of causticpotassa with quercetin is pushed further, the first-named substance is split upinto two new substances, viz., quercimeric and protocatechuic acids ; the formeris very soluble in water, alcohol, and ether, crystallises in granular masses,and is coloured a deep blue by perchloride of iron ; its reactions are rathersimilar to those exhibited by quercetic acid. Its formula is CgH 60 5 4 -H 2 0 .

Protocatechuic acid, C7H6O4, is soluble in ether; it takes a greenish-bluecolour with the salts of peroxide of iron : addition of alkaline carbonates turnsthis colour to a red. Neutral solutions of protoxide of iron (neutralised bymeans of carbonate of baryta) yield, with protocatechuic acid, a beautifulviolet colouration.

When a sodic solution of quercetin is heated with sodium amalgam untilthe deep brown first produced has become brownish-yellow, and the mixtureis next neutralised with hydrochloric acid, air being excluded, and the liquidshaken up with ether, phloroglucin and two other substances are isolated,one of which, C 7 H80 3 , is very soluble ; the other, insoluble but readilycrystallised, is C13H12O3. An alcoholic solution of quercetin, acidulated withhydrochloric acid, assumes, when in contadt with sodium amalgam, a purplecolour, and the liquid yields, on concentration, red crystals analogous toisomorin. This material kept in alcoholic solution reproduces quercetin veryreadily, especially if an alkali be present. Dr. Stein* first described this sub-stance as paracarthamin : it becomes yellow under the influence of alkalies,but acids restore the red colour; it differs from carthamin only by containingmore water.

Hlasiwetz and Pfaundler have fully described and illustrated, by a series offormulae, all the reactions and the results thereof relating to quercitrin and itsvarious derivatives, but as yet the precise molecular weight of quercitrin andquercetin are not established.

Use made of Quercitron.

Quercitron is met with in trade as a powder, and is also used in that statein dyeing. Relying upon the labours of M. Rigaud, and upon the splitting upof quercitrin into glucose and quercetin, M. Leeshing commenced, in 1855, toboil the quercitron with dilute sulphuric acid : if this operation is succeededby a thorough washing of the material with cold water, the result is theremoval of the tannin and lime-salts from the ware, and the conversion of thesoluble quercitrin into sparingly soluble quercetin. Leeshing boils for an hour,by means of a jet of steam, in a leaden tank supported by strong woodwork,80 gallons of water, 100 kilos, of concentrated sulphuric or 200 kilos, ofhydrochloric (sp. gr. 1*192), and 200 kilos, of quercitron : after standing theacid liquid is decanted, and the residue thoroughly washed with cold water,first by decantation and next on cloth filters, and the mass (purified quercitron)is finally strongly pressed.

Another plan is to boil 500 kilos, of quercitron with a solution of 15 kilos.

* “Zeitschrift fur Chemie und Pharmacie,” 1863, p.467. “Journal fur Prakt. Chemie,”v °l. lxxxv., p. 351, and vol. Ixxxix., p. 491.