Delphinium consolida, Flowers (Kaempferol)(CHAPTER VII. Flavonol Group.)(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.

Delphinium consolida is a common European plant belonging to the Larkspur family; its name refers to its powers, real or imaginary, of healing or consolidating wounds. The blue flowers were examined by Perkin and Wilkinson (Chem. Soc. Trans., 1902, 81, 585) to determine if these yield the same colouring matters as those previously isolated from the flowers of the D. zalil (ibid., 1898, 73, 267). The presence of kaempferol only could, however, be detected. For its isolation an aqueous extract of the flowers was digested at the boiling-point with addition of sulphuric acid, and the brown resinous product which separated on keeping, extracted with alcohol and the extract evaporated to a small bulk. Addition of ether to this solution caused the precipitation of resinous impurity, and on evaporating the ethereal liquid a semi-crystalline residue of the crude colouring matter was obtained. The product was crystallised from dilute alcohol, converted into acetyl derivative, and this after purification retransformed into colouring matter in the usual manner. The yield was approximately 1 per cent.

[---]

Kaempferol possesses well-defined dyeing properties, and gives with mordanted woollen cloth the following shades which closely resemble those given by morin (loc. cit.):
Chromium. Brownish-yellow.
Aluminium. Yellow.
Tin. Lemon-yellow.
Iron. Deep olive-brown.

It is also present in the Impatiens balsamina (Chantili Pass), the Erythrina stricta (vernacular name "Kon kathet"), (Perkin and Shulman, Chem. Soc. Proc., 1914, 30, 177), the berries of the Rhamnus catharticus (loc. cit.), and together with quercetin, both apparently as glucosides, in the flowers of the Prunus spinosa (Perkin and Phipps, Chem. Soc. Trans., 1904, 85, 56). For the separation of the two colouring matters a fractional crystallisation from acetic acid was employed, kaempferol in these circumstances being the more sparingly soluble.

Galanga Root(CHAPTER VII. Flavonol Group.)(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.

Galanga root is the rhizome of Alpinia officinarum (Hance) and is a native of China. It is employed in the form of a decoction as a remedy for dyspepsia.

Galanga root was first examined by Brandes (Arch. Pharm., (2), 19, 52), who isolated from it a substance which he named kaempferide, but this, according to Jahns (Ber., 1881, 14, 2385), was a mixture of three substances, kaempferide, alpinin, and galangin. The subject was later examined by Gordin (Dissert., Berne, 1897), and by Ciamician and Silber (Ber., 1899, 32, 861) and Testoni (Gazzetta, 1900, 30, ii., 327), and it is now clearly demonstrated that galanga root contains kaempferide, galangin, and galangin monomethylether. According to Testoni, the alpinin of Jahns is a mixture of galangin and kaempferide.

Kaempferide, C₁₆H₁₂O₆, consists of yellow needles, melting-point 227-229°, soluble in alkaline solutions with a yellow colour. Sulphuric acid gives a blue fluorescent yellow solution.

[---]

Galangin, C₁₅H₁₀O₅, the second constituent of galanga root, crystallises in yellowish-white needles, melting-point 214-215°, soluble in alkaline solutions with a yellow colour. With acetic anhydride, it gives a triacetyl derivative, C₁₅H₇O₅(C₂H₃O)₃, melting-point 140-142° (Jahns), and by means of methyl iodide a dimethylether, C₁₅H₈O₃(OCH₃)₂, melting-point 142°.

[---]

[---] Galangin dyes with mordanted woollen cloth the following shades:
Chromium. Olive-yellow.
Aluminium. Yellow.
Tin. Lemon-yellow.
Iron. Deep olive.

[---]

CHAPTER VII. Flavonol Group.Introduction, Flavonol

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.

It is usual to subdivide the great family of yellow colours derived from flavone into two classes, flavone and flavonol, and the latter group is distinguished by the fact that the hydrogen in the γ-pyrone ring of these compounds is substituted by hydroxyl, whereas in the former it is not.

Flavonol) so designated by v. Kostanecki, was synthesised by v. Kostanecki and Szabranski (Ber., 1904, 37, 2819) in the following manner:

By the action of amyl nitrite and hydrochloric acid in alcoholic solution on flavanone, isonitrosoflavanone, melting-point 158-159°, is produced, and this by means of boiling dilute acids splits off hydroxylamine and is converted into flavonol.

Flavonol crystallises from alcohol in yellow needles, melting-point 167-170°. When warmed with aqueous sodium hydroxide it forms a yellow liquid, and on cooling the sodium salt separates in the form of yellow needles. Its solution in sulphuric acid exhibits an intense violet fluorescence. Acetylflavonol, colourless needles, melts at 110-111°.

According to Auwers and Müller (Ber., 1908, 41, 4233) benzylidenecoumaranones can be converted into flavonols. Thus benzylidene 4 methylcoumaranone dibromide when treated with potassium hydroxide gives 2 methylflavonol. The reaction may be thus expressed : [KUVA PUUTTUU]

The hydrolysis of flavonol into 0-hydroxybenzoylcarbinol and benzoic acid may be expressed by the following equations [KUVA PUUTTUU] and this reaction, which is typical of the behaviour in these circumstances of the whole series of these compounds, has in general been employed to ascertain their structure. It is best effected by digesting the fully methylated flavonols with boiling alcoholic potash for some hours, for owing to the occurrence of secondary reactions it cannot be satisfactorily carried out with the unmethylated compounds.

For the synthesis of numerous flavonols, many of which occur naturally, v. Kostanecki and his co-workers have employed as a general method that found serviceable for the preparation of flavonol itself, and many instances of this are given in the sequel. The flavonols, with the exception of morin, which curiously enough is colourless, are yellow crystalline substances, soluble in alkaline solutions with a yellow colour, and yield with ease in the presence of acetic acid orange crystalline oxonium salts. According to Perkin, whereas as a rule hydroxyflavones are not oxidised by air in alkaline solution and can be precipitated therefrom unchanged by acids, flavonols on the other hand are readily decomposed in this manner with the formation of water-soluble products.

Interesting is the fact that though certain colouring matters of this group do not possess two hydroxyls in the ortho-position relatively to one another, they are nevertheless strong dyestuffs, and of these the tetrahydroxyflavonol morin may be taken as an example [KUVA PUUTTUU]

That this peculiarity arises from the presence of the pyrone hydroxyl is evident if the structure of morin is compared with the lotoflavone of Dunstan and Henry (loc. cit.) the tinctorial properties of which are exceedingly feeble. It seemed possible that this dyeing effect was to be attributed to the fact that this compound contains the hydroxyl (i) in the peri-position to the chromophore and which is present in most of the natural dyes of this group. Such a suggestion, however, became untenable on the synthesis of resomorin by Bonifazi, v. Kostanecki, and Tambor (Ber., 1906, 39, 86), which dyes the same shades as morin but does not contain the peri-hydroxyl in question. Evidently therefore the tinctorial properties of these hydroxy flavonols can only be accounted for by their possession of the grouping [KUVA PUUTTUU] the effect of which is considerably strengthened by the presence of hydroxyls in other positions in the molecule, and this has received support from the observation of v. Kostanecki and Szabranski that flavonol itself dyes on aluminium mordant a pale yellow shade. Though ortho-hydroxyl groups are not essential to the dyeing property of hydroxyflavonols, their presence, at least in certain positions, has considerable influence, not only in deepening the tone, but also in reddening the shade. Thus, whereas morin dyes bright yellow shades, quercetin gives a brown-orange shade on aluminium mordant, and the effect of the pyrone hydroxyl is very evident on comparing quercetin with luteolin which gives in the same way only a bright yellow colour. A multiplication of hydroxyls does not effect any general alteration of shade given by these compounds, as is so well known to take place in the anthraquinone group, and this affords support to the theory of Watson previously mentioned.

The shades given by the flavonols are not so fast to light as those given by the flavone luteolin, and this may arise in part owing to the greater susceptibility of their salts (or lakes) to oxidation. In this respect they vary again among themselves, quercetin being a somewhat faster colour than fisetin, and morin than quercetin.

On the other hand, the character of the shade given by the natural dyestuff varies in tone, as to whether the colouring matter is present as glucoside or in the free condition. Thus in dyeing with quercitron bark, quercitrin and not quercetin is the dyestuff, whereas in old fustic no glucoside is present, and the tinctorial effect is due to morin itself. The shade again given by a glucoside is naturally dependent on the position of the sugar nucleus, and thus the quercetin glucoside, quercimeritrin (see Cotton Flowers) has quite distinct properties in this respect from quercitrin itself. Again, a glucoside may be almost devoid of tinctorial property, as in the case of the kaempferol glucoside robinin and the alizarin glucoside ruberythric acid. The idea formerly held that glucosides in general were not true dyestuffs, and that during the dyeing operation by the action of the mordant they were hydrolysed with production of the colour lake of the free colouring matter, is incorrect. This evidently arose from the fact that in certain of these dyestuffs, as, for instance, madder and Persian berries, the glucoside is accompanied by its specific enzyme, which in case the temperature of the dye-bath is gradually raised from the cold upwards, effects the hydrolysis of the glucoside before the dyeing operation has really commenced.

In the following pages the natural dyestuffs containing flavonols, or their glucosides, are as far as possible arranged as to the number of hydroxyls present in the colouring matter, commencing with those which contain least. As, however, in many plants more than one flavonol is present, it has obviously not been possible to adhere strictly to this method of classification.

Butea frondosa(CHAPTER VI. The Chalkone and Flavanone Groups.)(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.

The Butea frondosa, also called Dhak or Pulas, is a fine tree, 30-40 feet high, belonging to the order Leguminosæ. It is common throughout India and Burma, and is found in the North-West Himalaya, as far as the Jhelum River. The flowers, which in the dried condition are known as tísu, késú, kesuda or palás-képpúl, have a bright orange colour, and, although they are much larger, closely resemble in appearance the common gorseflower (Ulex europæus) with which, indeed, they are botanically allied. Large quantities of the flowers are collected in March and April, and employed by the natives to produce a yellow dye, much used during the "Holi" festival. The dyeing operation, which consists in steeping the material in a hot or cold decoction of the flowers, is virtually a process of staining, because the colour can be readily washed out. On the other hand, a more permanent result is sometimes produced either by first preparing the cloth with alum and wood ash or by adding these substances to the dye-bath.

From the Butea frondosa is also obtained the so-called "Butea gum" or "Bengal kino," employed by the natives for tanning leather, and the tree is of additional interest because in many parts of India the lac insect (Coccus lacca) is reared upon it. This latter, as is well known, causes the formation of stick lac, from which shellac and lac dye are prepared.

Butin, C₁₅H₁₂O₅. The flowers are extracted with water, and the extract digested boiling with a little sulphuric acid. A light viscous precipitate devoid of dyeing property separates, and this is removed while hot and the filtrate left over-night. The clear liquid is now decanted from a small quantity of tarry substance, and partially evaporated on the water-bath. A further quantity of a black viscous precipitate thus separates, and when this has been removed the filtrate, after some days, deposits crystals of the colouring principle. For purification the product is dissolved in a little alcohol, the mixture poured into ether, and the solution well washed with water. The liquid is evaporated, and the residue repeatedly crystallised from dilute alcohol (Perkin and Hummel, Chem. Soc. Trans., 1904, 85, 1459).

[---]

* This result has been criticised by Goschker and Tambor, who by the employment of mordanted calico obtained from butin very weak shades. It is, however, certain that by the use of mordanted wool a conversion of butin into butein occurs.Butin and butein dye mordanted woollen cloth identical shades, though as butin gives with an alcoholic lead acetate a practically colourless precipitate, it is not to be regarded as a colouring matter. In other words, butin is merely a colouring principle, and is converted during the dyeing operation by the action of the mordant into the colouring matter butein.*

The following shades are obtained: Chromium. Reddish-brown,
Aluminium. Brick-red
Tin. Full-yellow
Iron. Brownish-black,
and these are strikingly similar to those yielded by some of the hydroxybenzylidenecoumaranones artificially prepared by Friedlander and Rüdt (Ber., 1896, 29, 879) (see above).

The butea flowers contain but a trace of free butin or butein, and the glucoside present, which has not yet been isolated, is probably that of butin. This glucoside does not decompose readily during the dyeing process, hence the flowers do not dye mordanted cotton. In wool-dyeing, where acid-baths are employed, a better result is obtained, although in this case the shades possess but little strength. If the glucoside is first hydrolysed by boiling the flowers with dilute hydrochloric acid, or if sulphuric acid is employed, and the acid then neutralised with sodium carbonate, on evaporation a material is obtained which readily dyes by the usual methods. Such products give the following shades: with chromium, deep terra-cotta; with aluminium, a bright orange; with tin, bright yellow; and with iron, a brownish-olive. The chromium colour is characteristic, and is much redder in tint than that yielded by any known natural yellow dye.

Scoparin, Scutellarein(CHAPTER V. The Flavone Group.)(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.

Cytisus scoparius Jänönpapu, jänönvihma

Scoparin, the colouring matter of the Cytisus scoparius (Link.), has been investigated by Stenhouse (Annalen, 78, 15), by Hlasiwetz (Annalen, 138, 190), and by Goldschmiedt and Hemmelmayer (Monatsh., 14, 202).

[---]

Scutellarin. If the flowers and leaves of Scutellaria altissima are extracted with water the solution on keeping deposits crystals of scutellarin, C₂₁H₁₈O₁₂ (Molisch and Goldschmiedt, Monatsh., 1901, 22, 68; Goldschmiedt and Zerner, ibid.) 1910, 31, 439). It melts above 310, is sparingly soluble in the usual solvents, and the alcoholic solution gives with lead acetate a red precipitate, and with ferric chloride a green coloration passing into red on heating. With the haloid acids and sulphuric acid in the presence of acetic acid orange-red crystalline oxonium compounds separate, which are readily decomposed in contact with water.

[---]

Fukugi(CHAPTER V. The Flavone 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.

The Japanese dyestuff "fukugi" (botanical origin unknown) [EDIT: Garcinia subelliptica] has, at least until recently, been employed to a considerable extent in Japan as a mordant dyestuff. It consists of the wood of a tree which when ground forms an almost colourless powder, the extract of which is sold in the form of brittle rectangular cakes of a yellowish-brown colour.

Fukugetin, C₁₇H₁₂O₆, the colouring matter, forms minute canary-yellow prismatic needles melting at 288-290° (Perkin and Phipps, Chem. Soc. Trans., 1904, 85, 58). It dissolves in alkaline solutions with a yellow colour, and gives with alcoholic lead acetate an orange-yellow precipitate and with alcoholic ferric chloride a brown-black coloration.

Crystalline acetyl and benzoyl derivatives of this colouring matter could not be obtained, but the bromine compound, C₁₇H₁₀O₆Br₂, minute flat needles, melting-point 280°, is readily prepared by the action of bromine on fukugetin in the presence of acetic acid. Fukugetin dyes mordanted fabrics shades which are almost identical with those given by luteolin - Chromium. Dull orange-yellow,
Aluminium. Orange-yellow,
Tin. Bright yellow,
Iron. Olive brown,
and resembles this colouring matter in that its alkaline solution is not oxidised on exposure to air. By fusion with alkali fukugetin gives phloroglucinol and protocatechuic acid.

The dyeing properties of "fukugi" are analogous to those of weld. The similarity in shade indeed is so marked that except in point of strength for fukugi is a stronger dye than weld it is impossible to distinguish between them.

Dyer's Broom.(CHAPTER V. The Flavone 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.

Genista tinctoria, Linn. {Dyer's broom, Dyer's greenweed; Genet, Genestrole, Trentanel, Fr.; Ginster, Ger.) is found in the pastures, thickets, and waste places throughout Central and Southern Europe, across Russian Asia to the Baikal, and northward to Southern Sweden. It is frequent in the greater part of England, but rare in Ireland and Scotland. The fact that it contains a yellow colouring matter is recorded by numerous writers, and the following embody the principal references to the dyeing and general properties of the plant: Bancroft ("Philosophy of Permanent Colours," 1813, 2, 108); Gmelin ("Handbook of Chemistry," 16, 517); Berthollet ("On Dyeing," 1824, 2, 242); Gonfreville ("L'Artdela Teinturedes Laines," 501); Leuchs ("Farben u. Farbekunde," 1846, 2, 309), and Schützenberger ("Traite des Matieres Colorantes," 1867, 4, 422).

To isolate the colouring matters, a hot aqueous extract of the plant is treated with lead acetate solution, and the pale yellow viscous precipitate is collected and decomposed by means of boiling dilute sulphuric acid. The clear liquid decanted from the lead sulphate deposits on cooling a dull yellow powder; this is filtered off, dissolved in a little alcohol, and the solution poured into a large volume of ether, causing the separation of a dark-coloured resinous impurity. The clear liquid is evaporated, yielding a yellow crystalline residue, which consists of two substances. To separate these, advantage is taken of the fact that, with sulphuric acid in the presence of acetic acid, one only of these compounds gives an insoluble sulphate. This is collected and decomposed with water and the product crystallised from dilute alcohol. It is obtained as yellow needles, and was found to be identical with the luteolin of weld (Reseda luteola) (Perkin and Newbury, Chem. Soc. Trans., 1899, 75, 830).

Genistein, C₁₄H₁₀O₅, the second colouring matter of dyer's broom, is present in the mother liquors obtained during the purification of the luteolin, and also in considerable quantity in the filtrate from the lead precipitate, from which it is most readily isolated. To the boiling liquid ammonia is added, causing the separation of a lemonyellow precipitate, which is collected and decomposed with boiling dilute sulphuric acid. The clear liquid is extracted with ether, and the extract evaporated, leaving a brownish crystalline mass. It is purified by crystallisation from acetic acid, and by conversion into the acetyl derivative.

Genistein crystallises in long colourless needles; melting-point 291-293° (Perkin and Horsfall, Chem. Soc. Trans., 1900, 77, 1312); soluble in alkalis with a pale yellow coloration. Alcoholic ferric chloride gives a dull-red violet coloration, and alcoholic basic lead acetate a lemon-yellow precipitate.

Triacetylgenistein, C₁₄H₇O₅(C₂H₃O)₃, colourless needles, melting-point, 197-201°; and tetrabromgenistein, C₁₄H₆Br₄O₅, colourless needles, melting-point above 290°, have been described.

On digestion with boiling 50 per cent, potassium hydroxide, genistein gives phloroglucinol and p-hydroxyphenylacetic acid.

By methylation with methyl iodide in the usual manner, genistein dimethyl ether and methylgenistein dimethyl ether are produced.

Genistein dimethyl ether, C₁₄H₈O₃(OCH₃)₂, forms colourless leaflets, melts at 137-139°, and gives the monacetyl compound, C₁₄H₇O₃(C₂H₃O)(OCH₃)₂, minute colourless needles, melting-point 202-204°. When decomposed with alcoholic potash, it forms methoxyphenylacetic acid and phloroglucinol-monomethyl ether (identified by means of its disazobenzene derivative).

Methylgenistein dimethyl ether,
CH₃.C₁₄H₇O₃(OCH₃)₂, melts at 202°; and the acetyl derivative,
CH₃.C₁₄H₆O₃(C₂H₃O)(OCH₃) ₂,
forms colourless needles, melting-point 212-214°. With alcoholic potash it gives methoxyphenylacetic acid and probably methylphloroglucinol-monomethyl ether.

Genistein diethyl ether, C₁₄H₈O₃(OC₂H₅)₂, forms colourless needles, melting-point 132-134°; whereas acetylgenistein diethyl ether, C₁₄H₇O₃(C₂H₃0)(OC₂H₅)₂, melts at 168-170°. Alcoholic potash gives p-ethoxyphenylacetic acid.

According to Perkin and Horsfall, genistein is most probably a trihydroxyphenylketocumaran.

Genistein is a feeble colouring matter, and upon woollen cloth gives, with chromium mordant, a pale greenish-yellow; with aluminium mordant, a very pale yellow; and with iron mordant, a chocolate- brown shade.

Dyeing Properties of Dyer's Broom.

-In this respect there is a close resemblance between dyer's broom and weld. The dyeing power of the former is distinctly the weaker of the two; otherwise the only point of difference worthy of mention is that shown by the iron mordant, which, in the case of dyer's broom, gives a duller and more drab-coloured shade. Luteolin is also present in the Digitalis purpurea (digito-flavone), (Fleischer and Fromm, Ber., 1899, 32, 1184; v. Kostanecki and Diller, ibid.) 1901, 34, 3577), and in the flowers of Antirrhinum majus (Wheldaleand Bassett, Biochem. Jour., loc. cit.).

Weld(CHAPTER V. The Flavone Group.)(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.

Weld is the dried herbaceous plant known as Reseda luteola formerly cultivated to a considerable extent in France, Germany, and Austria. Its cultivation in this country has nearly ceased, because not only is the quantity of colouring matter it contains very small, but the carriage of the plant, owing to its bulky nature, is expensive. A special interest, however, attaches to weld, for it is said to be the oldest European dyestuff known, and was used by the Gauls and other nations dwelling north of the Alps in the time of Julius Caesar.

The plant attains a height of about 3 feet, is pale brown in colour, and is sold in sheaves like straw. The colouring matter is disseminated throughout the entire plant, but the greater quantity occurs in the upper extremity and the seeds.

Luteolin, the main colouring matter of weld, was examined by Chevreul (J. Chim. Med, 6, 157; Annalen, 82, 53), who obtained it in a crude condition; its isolation in a state of chemical purity was first achieved by Moldenhauer (Annalen, 100, 180), who assigned to it the formula C₂₀H₁₄O₈. It was subsequently investigated by Schützenberger and Paraf (Bull. Soc. Chim., 1861, (i.), 18), who proposed the formula C₁₂H₈O₅ and purified it in a somewhat novel manner which is worthy of mention. Weld was exhausted with alcohol, the extract evaporated, and treated with water, which threw down a dirty greenish precipitate. This was collected, introduced with a little water into a sealed tube and heated to 250°. On cooling the sides of the tube were found to be coated with golden-yellow needles of luteolin, and the impurities had collected at the bottom of the tube to form a resinous cake.

Hlasiwetz suggested that luteolin had the formula C₁₅H₁₀O₆ and was isomeric with the paradiscetin, which he obtained during the fusion of quercetin with alkali (Annalen, 112, 107).

For the preparation of luteolin in quantity, Perkin (Chem. Soc. Trans., 1896, 69, 206, 799) employs weld extract.

300 gms. of the extract dissolved in 3 litres of water is treated with 100 c.c. of hydrochloric acid (33 per cent.), and the mixture is digested at the boiling temperature for some hours. A quantity of a black resinous substance separates, which is collected while hot, and the filtrate, which contains the colouring matter, is allowed to stand for twelve hours. A brown precipitate of impure luteolin is slowly deposited, and is collected, washed, and dissolved in a little hot alcohol. On pouring this solution into ether, the main bulk of the impurity is precipitated, and the ethereal liquid on evaporation yields a yellow residue, which is crystallised from dilute alcohol. The product in addition to luteolin contains apigenin (Chem. Soc. Trans., 1900, 77, 1315), and the latter can only be removed with certainty by the following method: -

The mixture dissolved in boiling glacial acetic acid is treated with a few drops of strong hydrochloric acid; this causes the almost immediate separation of luteolin as hydrochloride, whereas the apigenin remains in solution. The hydrochloride is collected, decomposed by water, and the luteolin crystallised from dilute alcohol.

[---]

It has already been stated that weld contains a second colouring matter, Apigenin (v. Parsley).

Dyeing Properties of Weld.

The importance of weld as a dyestuff in silk and wool dyeing has greatly diminished in consequence of its low colouring power compared with quercitron bark, flavin, and old fustic. This in one respect is unfortunate, because, of all the natural yellow colouring matters, it yields the purest and fastest shades. In conjunction with aluminium and tin mordants it gives very bright pure lemon-yellow colours, and these do not change to an olive or reddish tint as in the case with other vegetable yellows. With chromium and iron mordants weld gives yellowish and greenish olives respectively. For yellow, wool and silk are mordanted with alum and tartar in the usual manner and dyed subsequently in a decoction of weld with the addition of chalk to the dye-bath. Weld alumina yellow is to some extent still employed in this country for certain army cloths and braid. For silk dyeing, weld extract is manufactured in small quantity, and is used for the production of yellow and olive colours.

Lotus arabicus(CHAPTER V. The Flavone 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.

The L. arabicus (Linn.) is a leguminous plant, indigenous to Egypt and Northern Africa, and in the young condition is extremely poisonous. It has been investigated by Dunstan and Henry (Phil. Trans., 1901, 194, 515).

Lotusin, the active principle, can be isolated by extracting the dried plant with methyl alcohol. The extract is evaporated, the residue treated with water to remove chlorophyll and resin, and from the aqueous solution tannin and other impurities are precipitated by means of lead acetate. The nitrate, on evaporation, leaves a syrupy residue, from which crystals of lotusin slowly separate. In the pure condition lotusin, C₂₈H₃₁NO₁₆, forms yellow needles, and when hydrolysed by digestion with hydrochloric acid, or by means of an enzyme lotase, also found in the plant, yields dextrose, lotoflavin, and hydrocyanic acid, according to the following equation:
C₂₈H₃₁O₁₆N + 2H₂O = 2C₆H₁₂O₆ + C₁₅H₁₀O₆ + HCN

When warmed with alcoholic potash (20 per cent.) lotusin is gradually decomposed with production of ammonia and lotusinic acid:
C₂₈H₃₁O₁₆N + 2H₂O = C₂₈H₃₂O₁₈ + NH₃ (Lotusinic acid.)

This compound is monobasic, gives yellow crystalline salts, and is hydrolysed by dilute hydrochloric acid with formation of lotoflavin dextrose and heptogluconic acid:
C₂₈H₃₂O₁₈ + 2H2 = C₁₅H₁₀O₆; + C₆H₁₂O₆ + C₇H₁₄O₈

Lotoflavin, C₁₅H₁₀O₆, crystallises in yellow needles, soluble in alkaline solutions with a yellow colour. By fusion with alkali, phloroglucinol and β-resorcylic acid are produced.

With acetic anhydride lotoflavin gives a tetra-acetyl compound, C₁₅H₆O₆(C₂H₃O)₄, colourless needles, melting-point 176-178°, and when methylated by means of methyl iodide the trimethyl ether, C₁₅H₇O₃(OCH₃)₃, is obtained. This latter compound exists in two forms, viz. the a-form yellow rosettes, melting-point 125°, and the -form glistening needles, melting-point 175°, which are mutually convertible. Both varieties give by means of acetic anhydride the same monoacetyl-lotoflavin trimethyl ether, C₁₅H₆O₃(C₂H₃O)(OCH₃)₃, yellow needles, melting-point 147°.

According to Dunstan and Henry, lotoflavin is probably a tetrahydroxyflavone, possessing the formula [KUVA PUUTTUU]

The hydrolysis of the cyanogenetic glucoside lotusin, with formation of maltose, lotoflavin and hydrocyanic acid, may be expressed by the equation
C₂₈H₃₁NO₁₆ + H₂O = C₁₂H₂₂O₁₁ + C₁₅H₁₀O₆ + HCN

The following constitutions are respectively assigned to lotusin (1) and lotusinic acid (2): [KUVA]

Saponaria officinalis(CHAPTER V. The Flavone Group.)(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.

The epidermal cells of the leaves of certain flowering plants contain, dissolved in their cell sap, a substance which is coloured blue by iodine. The colour disappears on warming and returns on cooling, as is the case with starch. On this account the compound was regarded as an amorphous variety of starch by Sanio, its discoverer (Botanische Zeitung, 1857, 15, 420). Schenck (ibid., 1857, 15, 497, 455) doubted whether this substance was identical with starch, and the correctness of this view was confirmed by Nageli (Beitrage zur wissensch. Botanik, 1860, 2, 187). For the chemical examination of this substance the dried shoots of the S. officinalis were selected by Barger (Chem. Soc. Trans., 1906, 89, 1210) as the raw material, because this plant is relatively rich in the compound, and is grown on the Continent for pharmaceutical purposes, so that large quantities are easily obtainable.

[---]

Vitex littoralis(CHAPTER V. The Flavone Group.)(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.

Vitex littoralis = Vitex lucens

The Vitex littoralis (A. Cunn.) or "Puriri" is a large tree, 40-60 feet high, and 3-5 feet in diameter, which grows only in the northern portion of the North Island of New Zealand. The wood affords a very durable timber, and is chiefly used for house blocks, fencing posts, piles for bridges, railway sleepers, etc.

Vitexin, the main colouring matter, is present in the wood in the form of a glucoside which has not yet been isolated. It is prepared by digesting a purified extract of the dyestuff with boiling dilute hydrochloric acid, and by this means separates in the form of a yellow viscous mass. By extracting this crude product with boiling alcohol, a pale yellow crystalline powder remains undissolved, and this, owing to its sparing solubility, is most readily purified by acetylation, and the subsequent hydrolysis of the pure acetyl derivative (Perkin, Chem. Soc. Trans., 1898, 74, 1020).

[---]

[---] Vitexin is a somewhat feeble colouring matter, and dyes shades similar to those given by apigenin; these, employing woollen cloth mordanted with chromium, aluminium, and tin, are respectively greenish-yellow, pale bright yellow, and pale brown.

In addition to vitexin the wood of the Vitex littoralis contains (as glucoside) a small quantity of a second colouring matter, homovitexin. It was obtained as a pale yellow powder, melting-point 245-246°, and is distinguished from vitexin by its ready solubility in alcohol. Fused with alkali it gives phloroglucinol and p-hydroxybenzoic acid, and is possessed of feeble dyeing property. The analytical figures approximate to C₁₆H₁₆O₇ or C₁₈H₁₈O₈.

According to Barger (Chem. Soc. Trans., 1906, 89, 1120) the glucoside saponarin, which is present in Saponaria offirinalis (Linn.), yields on hydrolysis glucose, saponaretin, and a small quantity of vitexin. It is possible that saponaretin and homovitexin are identical.

Robinia pseud-acacia(CHAPTER V. The Flavone 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.

Acacetin, C₁₆H₁₂O₅, the colouring matter of the leaves of the Robinia pseud-acacia (Linn.) (common or false acacia, North American locust), forms almost colourless needles, soluble in alkalis with a pale yellow coloration (Perkin, Chem. Soc. Trans., 1900, 71, 430.

To prepare it a boiling aqueous decoction of the leaves is treated with basic lead acetate solution, and the pale yellow precipitate is suspended in water and decomposed with boiling dilute sulphuric acid. From the clear liquid the colouring matter is removed by extraction with ether and purified by crystallisation from dilute alcohol.

Acacetin forms a diacetyl derivative, C₁₆H₁₀O₅(C₂H₃O)₂, colourless needles, melting-point 195-198°, and when fused with alkali gives phloroglucinol and p-hydroxybenzoic acid. Digested with boiling hydriodic acid it yields apigenin and one molecule of methyl iodide, and is consequently an apigenin monomethylether. Acacetin is very probably identical with von Gerichten's apigenin methyl ether (Ber., 1900, 33, 2908) - the acetyl derivative of which melts at 198-200°.

Interesting is the fact that the flowers of the Robinia pseud-acacia contain robinin, a glucoside of the trihydroxy flavonol kaempferol - which contains one more hydroxyl than apigenin. This is referred to later.

Chamomile Flowers(CHAPTER V. The Flavone 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.

Anthemis Nobilis. An examination of the flowers of Anthemis nobilis (Linn.) by Power and Browning (Chem. Soc. Trans., 1914, 105, 1833) has shown that these contain in addition to numerous other substances an apigenin glucoside, C₂₁H₂₀O₁₀.2H₂O, faintly yellow microscopic crystals melting at 178-180°. It dissolves in alkalis with a yellow colour and gives with aqueous ferric chloride a purplish-brown coloration. Dried at 125-130° it loses one molecule of water of crystallisation, but the second molecule cannot be eliminated without decomposing the substance. This is evident from the composition of the hexa-acetyl derivative, C₂₁H₁₄O₁₀(COCH₃)₆, colourless microscopic crystals, melting-point 144-146°, the molecule of water in question being eliminated in the process of acetylation.

By digestion with 5 per cent, aqueous sulphuric acid for three hours, this glucoside yields apigenin and dextrose according to the equation -
C₂₁H₂₀O₁₀, H₂O = C₁₅H₁₀O₅ + C₆H₁₂O₆

Parsley (Apiin, apigenin)(CHAPTER V. The Flavone Group.)(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.

Carum petroselinum = Petroselinum crispum = persilja

Apiin, the glucoside of apigenin, is found in the leaves, stem, and seeds of parsley (Carum (Apium) petroselinum, Benth. and Hook.), (Rump, Buchner's Repert. f. Pharm., 1836, 6, 6; Braconnot, Ann. Chim. Phys., 1843, iii., 9, 250). [---]

[---]

Apigenin closely resembles chrysin in its tinctorial properties, although it is a somewhat stronger dyestuff. The shades it gives upon wool mordanted with aluminium, chromium, and iron are respectively pure yellow, weak yellow-orange, and chocolate-brown.

Apigenin is also present in weld (Reseda luteola), (Perkin and Horsfall, Chem. Soc. Trans., 1900, 77, 1314), in the flowers of Antirrhinum majus (Wheldale and Bassett, Biochem. Jour., 1913, 7, 441), and exists probably also in chamomile flowers (Perkin).

Poplar Buds(CHAPTER V. The Flavone Group.)(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.

Chrysin, C₁₅H₁₀O₄, is contained in the leaf buds of the poplar (Populus pyramidalis, Salisb., P. nigra, Linn., P. monilifera, Ait.), in which it is present to the extent of about ¼ per cent. It was first isolated by Piccard (Ber., 6, 884, 1160; 7, 888; 10, 176) and is best prepared by the method devised by this chemist.

An alcoholic extract of 1000 grams of poplar buds is treated while hot with about 120 grams of lead acetate, and after standing for some time the yellow precipitate is removed. Through the clear filtrate sulphuretted hydrogen is passed in order to decompose lead salts, the sulphide of lead is filtered off and the liquid evaporated to dryness. The residue dissolved in a little hot alcohol gradually deposits crystals ofchrysin, which are collected, successively extracted with carbon disulphide, benzene, and boiling water, and finally crystallised two or three times from alcohol.

[---]

Chrysin is a feeble dyestuff. The shades produced on wool mordanted with aluminium, chromium, and iron, are respectively pale bright yellow, pale yellow-orange, and chocolate-brown.

Tectochrysin, a second constituent of poplar buds, is present in the benzene extracts from the crude chrysin. Tectochrysin is chrysin monomethylether, (C₁₅H₉O₃.OCH₃), (Piccard), and is identical with the methylation product of chrysin itself (loc. cit.).

Natural Flavone(CHAPTER V. The Flavone 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.

Very interesting is the occurrence of flavone in nature (Müller, Chem. Soc. Trans., 1915, 107, 872). It is well known that many varieties of the primula possess on their flower stalks, leaves, and seed capsules a characteristic dust termed by gardeners "meal" or "farina," and this is most pronounced on varieties recently obtained from China and Japan. This powder, examined by Hugo Müller who obtained it mainly from the [Primula] P. pulverulenta and P. japonica, dissolves readily in benzene and boiling ligroin, and the concentrated solution on cooling became semi-solid owing to the separation of crystalline tufts.

It possessed the formula C₁₅H₁₀O₂, melted at 99-100°, and on boiling with dilute sodium hydroxide gave slowly a yellow solution, with formation of a small quantity of acetophenone, and the latter could be obtained in greater quantity by the action of methyl alcoholic sodium hydroxide. Employing methyl alcoholic barium hydroxide, a reagent not previously suggested for the degradation of flavone compounds, Müller obtained a substance C₁₅H₁₂O₃. This by the action of alkalis was converted into salicylic acid and acetophenone and evidently consisted of hydroxy-benzoyl-acetophenone (0-hydroxy-dibenzoyl-methane)
OH.C₆H₄.CO.CH₂.CO.C₆H₅

The compound C₁₅H₁₀O₂ was thus without doubt flavone, and it is interesting to note that though hydroxybenzoyl-acetophenone was assumed by Feuerstein and v. Kostanecki (Ber., 1898, 31, 1758) to be the first product of the hydrolysis of this substance, its isolation in this manner had not previously been effected.

The function which flavone exercises in the economy of the plant life of the primula is difficult to explain, though it may be of service on account of its repellent action towards water.

Gentian Root(CHAPTER IV. The Xanthone 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.

The Gentiana lutea (Linn.), from which the gentian root is derived, chiefly occurs in mountainous districts, especially in Switzerland and the Tyrol. There is present in the root of this and other species of gentiana a bitter principle which is said to possess valuable tonic virtues, and on this account some quantity of the material is imported into this country for medicinal purposes.

Gentisin, the colouring matter of gentian root, was first isolated by Henry and Caventou (J. Pharm. Chim., 1821, 178), and was shown by Baumert (Annalen, 62, 106) to possess the formula C₁₄H₁₀O₆. Hlasiwetz and Habermann (ibid., 175, 63; 180, 343), somewhat later, found that gentisin contains two hydroxyl groups, and that, when fused with potassium hydrate, phlorglucinol and gentisic acid (hydroquinone carboxylic acid) are produced from it. By the action of hydrochloric acid on gentisin, methyl chloride was evolved, a probable indication of the presence of a methoxy group. To prepare gentisin (Baumert, loc. cit.}, the root is well washed with water, then extracted with alcohol, and the extract evaporated to a small bulk. The residue is washed with water to remove the bitter principle, and then with ether to extract plant wax. For purification, the crude colouring matter is repeatedly crystallised from alcohol; 10 kilos, of the root yield about 4 grams of the substance. Gentisin crystallises in yellow needles, is sparingly soluble in alcohol, and dissolves in alkaline solutions with a yellow colour.

Gentisein, C₁₃H₈O₅, 2H₂O. When gentisin is digested with boiling hydriodic acid, it is converted into gentisein with evolution of i molecule of methyl iodide. Gentisein consists of straw-yellow needles, melting at 315°, and gives with sodium amalgam a bloodred coloration, whereas gentisin, by a similar method, yields a deep green coloured liquid (v. Kostanecki, Monatsh., 12, 205). By the action of acetic anhydride, gentisein is converted into the triacetyl derivative, C₁₃H₅O₅(C₂H₃O)₃, needles, melting-point 226° (v. Kostanecki, loc. cit.}; but on methylation with methyl iodide, a dimethyl ether, C₁₃H₅O₂(OH)OCH₃)₂, yellow needles, melting-point 167°, is produced (v. Kostanecki and Schmidt, Monatsh., 12, 318).

Partial methylation converts gentisein into gentisin, and it is thus certain that the latter consists of gentisein monomethyl ether. v. Kostanecki and Tambor (Monatsh., 15, 1) obtained gentisein by distilling a mixture of phloroglucinol and hydroquinone carboxylic acid with acetic anhydride and its constitution is therefore represented as 1:3:7 trihydroxyxanthone. By a study of disazobenzene-gentisin, C₁₄H₈O₅(C₆H₅N₂)₂, scarlet-red needles, melting-point 251-252° (Perkin, Chem. Soc. Trans., 73, 1028), which gives the diacetyl derivative,
C₁₄H₆O₅(C₂H₃0)₂(C₆H₅N₂)₂,
orange-red needles, melting-point 218-220°, it has been shown that gentisin itself possesses the constitution. As gentisin yields by means of methyl iodide only a monomethyl ether, the original methoxy group cannot be in the position (1). On the other hand, if gentisin is represented by the formula (2) [KUVAT PUUTTUVAT], the azobenzene groups would enter the positions 4 and 2, and from such a compound an acetyl derivative cannot be obtained in the ordinary manner (compare disazobenzene phloroglucinol).

Gentisin is a feeble dyestuff, and gives on wool mordanted with chromium, aluminium, and tin, respectively, pale green-yellow, pale bright yellow, and very pale cream-coloured shades (Perkin and Hummel, Chem. Soc. Trans., 1896, 69, 1290).

Indian Yellow (Euxanthone).(CHAPTER IV. The Xanthone Group.)(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.

Indian yellow, Piuri, Purree, or Pioury, is a pigment mainly used in India for colouring walls, doors, and lattice-work, and by artists for water-colour work. On account of its disagreeable smell it is but rarely employed as a dyestuff. It is, or was, made almost exclusively at Monghyr in Bengal, and is obtained from the urine of cows which have been fed upon mango leaves. On heating the urine, usually in an earthen pot, the colouring matter separates out; this is pressed into a ball and dried partly over a charcoal fire and finally in the sun. It sold on the spot at about 1 rupee per lb. and is, or was, mainly sent to Calcutta and Patna. One cow produces, on the average, 3.4 litres of urine per diem, yielding 2 oz. (56 grams) of piuri. The yearly production is stated to have been from 100 to 150 cwts., which was probably over-estimated (v. Journ. Soc. Arts, 1883, (v.), 32, 16, and Annalen, 254, 268).

Piuri occurs in commerce in the form of round balls, which internally are of a brilliant yellow colour, whereas the outer layers are either brown or of a dirty green colour. The substance has a characteristic urinous smell. The undecomposed part consists only of euxanthic acid (C₁₉H₁₈O₁₁) in the form of a magnesium or calcium salt; the outer and decomposed portion contains in addition euxanthone, both free and combined. The composition of piuri seems to be variable; a fine sample, according to Graebe, contained
Euxanthic acid … 51.0
Silicic acid and alumina … 1.5
Magnesium … 4.2
Calcium … 3.4
Water and volatile matter … 39.0
[total] 99.1

[---]

Euxanthone possesses only feeble tinctorial properties; the respective shades obtained with woollen cloth mordanted with chromium, aluminium, and tin being dull brown-yellow, pale bright yellow, and very pale bright yellow (Perkin and Hummel, Chem. Soc. Trans., 1896, 69, 1290).

Maclurin(CHAPTER III. The Benzophenone Group.)(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.

This substance occurs, together with morin, in the wood of the tropical tree Chlorophora tinctoria (Gaudich), which comes into commerce as "Old Fustic".

The colouring matters of old fustic were first investigated by Chevreul ("Lemons de chimie applique a la teinture," ii., 150), who described two substances, one sparingly soluble in water, calledmorin, and a second somewhat more readily soluble. Wagner (Jour. f. pr. Chemie, (i), 51, 82) termed the latter moritannic acid) and considered that it had the same percentage composition as morin. Hlasiwetz and Pfaundler (Annalen, 127, 351), on the other hand, found that the so-called moritannic acid was not an acid, and as moreover its composition and properties were quite distinct from those of morin, they gave it the name "Maclurin".

When morin is precipitated from a hot aqueous extract of old fustic by means of lead acetate the solution contains maclurin. After removal of lead in the usual manner, the liquid is partially evaporated and extracted with ethyl acetate, which dissolves the colouring matter. The crude product is crystallised from hot water or dilute acetic acid (Perkin and Cope, Chem. Soc. Trans., 1895, 67, 943). A crude maclurin is also obtained during the preparation of fustic extract, partly in the form of its calcium salt, and this product may be purified with dilute hydrochloric acid and crystallised from water. In order to decolorise the crystals, acetic acid is added to a hot aqueous solution and a little lead acetate in such quantity that no precipitate is formed, and the solution is then treated with sulphuretted hydrogen. The clear liquid thus obtained is much less strongly coloured, and after repeating the operation two or three times, the maclurin, which crystallises out on standing, possesses only a pale yellow tint.

Maclurin, to which the composition C₁₃H₁₀O₆ was assigned by Hlasiwetz and Pfaundler (Jahresber., 1864, 558), consists, when pure, of almost colourless needles, which contain one molecule of water of crystallisation; the anhydrous compound melts at 200°C. (Wagner, Jahresber., 1850,529). The colouring matter is somewhat soluble in boiling water, is soluble in aqueous alkalis, forming pale yellow solutions, whilst with ferric chloride its aqueous solutions give a greenish-black coloration, and with aqueous lead acetate a yellow precipitate, which is soluble in acetic acid. When boiled with potassium hydroxide maclurin yields phloroglucinol and protocatechuic acid.

[---]

Patent Fustin.

Under the name "patent fustin" a colouring matter has been placed on the market, which consists chiefly of diazobenzene-maclurin (C. S. Bedford, 1887; Eng. Pat. 12667). To prepare this substance, old fustic is extracted with boiling water, the solution is decanted from the precipitate of morin and its calcium salt which separates on cooling, and is neutralised with the necessary quantity of sodium carbonate. Diazobenzene sulphate is then added until a precipitate no longer forms, and this is collected and washed with water. It is sold in the form of a paste, and dyes chrome mordanted wool an orange-brown shade.

Diazobenzene-maclurin (Bedford and Perkin, Chem. Soc. Trans., 1895, 67, 933; ibid., 1897, 71, 186), which crystallises in salmon-red prismatic needles, melting-point 270°C. (decomp.), has the following constitution: [KUVA PUUTTUU]

It dyes wool and silk direct from a weakly acid bath, in shades of orange, and on mordants gives colours varying from orange-red on aluminium and orange-brown on chromium, to olive on iron. The dyeings are fairly fast to washing.

---

Dyeing Properties of Maclurin.

With aluminium mordant maclurin gives a pale yellow, with chromium a yellow-green, and with iron a weak grey colour may be obtained.

Phloretin(CHAPTER III. The Benzophenone Group.)(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.

Phloretin occurs in the form of two distinct glucosides, phloridzin and glycyphyllin, which are found in the root-bark of the apple, cherry, and plum-tree, and in the leaves of Smilax glycyphylla respectively (cf. Rennie, Jour. Chem. Soc., 1887, 634); whilst by catalytic hydrogenation of naringenin, in alcoholic solution with palladous chloride and hydrogen, Franck (Beitr. Phys., 1, 179; cf. Chem. Centrbt., 1914, ii., 253) obtained a dihydro-naringenin which he considered to be identical with phloretin.

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.

[---]

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).

CHAPTER III. The Benzophenone Group.Introduction. (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.

Introduction

THIS group contains but one product, maclurin, that is of tinctorial value, and this substance has but feeble dyeing properties. Maclurin, however, found considerable commercial use at one time in the form of its dis-azobenzene derivative known as "Patent Fustin".

Besides maclurin, a number of hydroxylated derivatives of benzophenone occur in nature, but they have no tinctorial value. It has, however, been thought advisable to introduce a brief account of the two most important of these, viz. cotoïn and phloretin, in particular, in view of the attempt made by Perkin and Martin (Chem. Soc. Trans., 1897, 1149) to obtain from them products of tinctorial value similar to Patent Fustin".

Drosera whittageri(CHAPTER II. The Naphthoquinone Group.) (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.

Drosera whittakeri is found in Australia, and grows plentifully on the hills near Adelaide. The tuber of this plant consists of an inner solid but soft nucleus full of reddish sap or juice, and an outer series of easily detached thin, and more or less dry, layers of an almost black material. Between these layers are to be found small quantities of a brilliant red colouring matter, the amount varying in tubers of different size and age, but apparently more plentiful in the older plants (Rennie, Chem. Soc. Trans., 1887, 51, 371; 1893, 63, 1083).

The colouring matter is extracted from the tubers by means of hot alcohol, the solution evaporated, and the residue, containing a little alcohol, is then mixed with water and allowed to stand. The product is dried, sublimed, and the brilliant vermilion powder, which contains two substances, is fractionally crystallised from boiling alcohol, or acetic acid.

[---]

Lomatiol(CHAPTER II. The Naphthoquinone Group.) (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.

This colouring matter, which is closely related to lapachol, has been obtained from the seeds of the Lomatia ilicifolia and Lomatia longifolia, which occur in Australia (N.S.W. and Victoria).

The colouring matter is obtained by extracting the seeds with boiling water acidified with acetic acid, and allowing the filtered extract to cool, when the product crystallises out. It is recrystallised from the same solvent.

[---]

Lapachol.(CHAPTER II. The Naphthoquinone Group.) (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.

This colouring matter has been obtained from the wood of the Lapacho tree, from Greenheart wood, and also from Bethaberra wood. It was from the first-named that Arnaudon (Comptes rend., 1858, 46, 1154) originally obtained it by extracting the wood with alcohol, and recrystallising the product from a mixture of alcohol and ether. Stein (J. f. pr. Chem., 99, 1) showed that the same colouring matter was present in Greenheart wood, whilst Green and Hooker (Amer. Chem. Jour., 11, 267) obtained it from Bethaberra wood.

According to Paternò (Gazetta, 12, 337; 21, 374) the colouring matter is best extracted from the wood by means of soda solution (1 gram soda crystals in 16 grams water for 20 grams finely divided wood), the product being precipitated from the combined extracts by means of hydrochloric acid, purified by extraction with barium hydroxide solution and reprecipitation with acid. The product thus obtained when recrystallised from benzene is readily obtained in a pure condition.

Kermes(CHAPTER I. The Anthraquinone Group.)(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.

Kermes is the most ancient dyestuff on record, for it was known in the time of Moses, and is mentioned in Scripture by its Hebrew name, "tola" or "tolaschani". According to Tychsen (Bancroft's "Philosophy of Permanent Colours," i, 394), "the scarlet or kermes dye was known in the East in the earliest ages before Moses, and was a discovery of Phoenicians in Palestine, but certainly not of the small wandering Hebrew tribes". Under the name "coccus" it is frequently referred to by the Greek and Latin writers.

Kermes is an insect found on the oak kermes (Quercus coccifera, Linn.), and when living the female insects, which are fixed to the twigs of the tree, resemble bluish berries, and are covered with a whitish powder. As soon as their eggs are on the point of hatching these insects should be collected, killed by exposure to the steam of vinegar, and dried, and the product has then the appearance of pale reddish-brown grains. According to Bancroft, it would require 10 or 12 lbs. of kermes to produce the effect of a single lb. of cochineal.

Kermesic acid, C₁₈H₁₂O₉, the colouring matter of kermes, was first isolated, in the crystalline condition, by Heisse (Arbeit, a. d. K. Gesundheitsamte, 1895, 513), and has since been examined by Dimroth (Ber., 1910, 43, 1387; and Annalen, 1913, 399, 43). To isolate the kermesic acid, the kermes is first extracted with ether to remove wax, and this has been examined by Dimroth and Sherndal (Annalen, 1913, 399, 43), and identified as ceryl cerotate, C₅₂H₁₀₄O₂. The residue is then allowed to stand overnight with an ethereal solution of hydrochloric acid, by which means the kermesic acid, which exists in kermes in the form of a salt, is liberated and made capable of removal by repeated extraction with ether. For the purification of the substance, it is converted into its sparingly soluble sodium salt, which allows of its separation from flavo-kermesic acid, a substance stated by Dimroth to be present in kermes dye to the extent of about 0.06 per cent. the sodium salt of this being soluble in hot 2N sodium acetate solution, whereas the disodium salt of kermesic acid is almost insoluble. The sodium salt when dissolved in boiling sodium hydroxide solution and treated, whilst boiling, with excess of hydrochloric acid, yields a crystalline precipitate of kermesic acid.

---

Kermesic acid is thus closely related to carminic acid, which is also considered by Dimroth to be a derivative of anthraquinone.

Dyeing Properties.

According to Hellot (Bancroft, "Philosophy of Permanent Colours," i, 404), "the red draperies of the figures exhibited in the ancient Brussels and other Flemish tapestries were all dyed with kermes". "The fine red or crimson colour of these tapestries, which was originally called simply scarlet, took the name of Venetian scarlet, after the cochineal scarlet upon a tin base was discovered...."

For the production of this scarlet, the wool, previous to dyeing, was mordanted with alum and tartar; and, according to Bancroft, there is no evidence even in more recent years of the employment of a tin mordant in respect of this colouring matter, although the experiments he carried out indicated that by this latter method a scarlet could be produced "in every respect as beautiful and estimable as any which can be dyed with cochineal".

Lac Dye(CHAPTER I. The Anthraquinone Group.)(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.

Lac dye is produced by an insect, the Coccus lacca or ficus, living on the twigs of various kinds of trees, particularly the Ficus religiosa (Linn.), the Zizyphus jujuba (Lam.), and the Butea frondosa (Roxb.). These insects appear usually in November, and subsequently fasten themselves to the fleshy portions of the young branches. Gradually the abdomen of the insects becomes covered by a viscous fluid, which slowly forms a cellule surrounding the animal. The substance composing this cellule is the stick lac. The cellule attains its full size in March, and the insect then exhibits the appearance of a red oval- shaped, smoothly polished lifeless sack entirely filled with a beautiful red liquid; its size is then the same as that of the fully grown cochineal (Crookes, "Dyeing and CalicoPrinting," p. 354). Commercial stick lac is chiefly gathered on the hilly banks of the Ganges in India, that for dyeing purposes possessing a deep red colour, whereas the pale perforated kind in which no insects exist is employed for varnish-making, and constitutes the material for shellac.

Of lac, the following varieties occur: stick lac, the crude product together with the twigs upon which it is formed: grained lac, the material removed from the twigs; and caked lac, the latter variety fused and cast into moulds.

Such a resinous material is not suitable for dyeing purposes, and a simple process is adopted to remove the colouring matter from the resin, or at least to obtain it in a more concentrated form. This consists in extracting the stick lac with hot dilute sodium carbonate solution, evaporating the extract, and moulding the residue into square cakes. According to Crookes (loc. cit.) the product, which is lac dye, contains on an average about 50 per cent, of colouring matter, 25 per cent, of resin, and 22 per cent, of earthy impurities.

Lac dye is an extremely ancient dyestuff, and was employed in the East for many centuries before it was known in Europe. It appears to have been introduced into this country about 1790. Early in the last century, lac dye was a very important article of commerce, so much so that at one time shellac was practically a bye-product of its manufacture. The position of these products has now been reversed, for whereas the dyestuff is almost defunct, the shellac industry is of considerable importance.

According to the older writers, the colouring matter of lac dye was considered to be identical with that of cochineal, but that this is not the case has been clearly indicated by Schmidt (Ber., 20, 1285).

---

Dyeing Properties.

The dyeing properties of lac dye are practically identical with those of cochineal, but the shades obtained are somewhat faster. Owing to the resinous and mineral impurities accompanying the colouring matter, it is not readily soluble in water, and before use it is therefore ground to a paste with the requisite quantity of tin spirit together with a little hydrochloric acid, and allowed to stand overnight. Cochineal and lac dye can be used together with advantage, or after the wool is dyed with lac it may be entered into a fresh bath with cochineal. Its employment at the present time is, however, extremely limited.

Fowler (Indian Textile Jour., 1917, 244) has made attempts to standardise various Indian colouring matters so that they may be marketed in uniform strengths. It would appear that "Lac dye" is one of those with which he has been concerned.

Cochineal. Dyeing Properties of Cochineal.(CHAPTER I. The Anthraquinone Group.)(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.

Cochineal has been little employed in cotton dyeing, but was very largely used in silk and wool dyeing. It has now been practically replaced by the azo-scarlets.

Two shades of red are obtained upon wool with cochineal, namely, crimson, which is produced by means of aluminium sulphate, and a very fiery scarlet, for which stannous and sometimes stannic chlorides are employed.

For crimson, wool is mordanted with aluminium sulphate and tartar, and is then dyed in a separate bath with cochineal. The employment of calcium salts in the dyeing operation is not beneficial. Fairly good shades of crimson can also be obtained by mordanting and dyeing in a single bath with aluminium sulphate, oxalic acid, and cochineal. For scarlet, wool can be mordanted with stannous chloride and tartar, and dyed in a separate bath with cochineal. A single-bath method, employing stannous chloride, oxalic acid, and cochineal, has, however, been very largely used for this purpose. On the other hand, preparations of stannic chloride, known as "tin spirits," "scarlet spirits," and "nitrate of tin," are and have been much employed by dyers of cochineal scarlet. Though, when used alone, stannic chloride does not give such brilliant shades as the stannous mordant, a mixture of both is considered to be beneficial. For very yellow shades of scarlet, yellow colouring matters can be added to the cochineal dye-bath, and of these "flavine" has been considerably employed.

Cochineal red on wool possesses considerable fastness to light, but has the defect that weak alkalis and soap cause it to acquire a duller or more bluish shade.

Wool mordanted with potassium dichromate gives with cochineal a good purple colour, whereas with ferrous sulphate and tartar, purplish, slate, or lilac colours can be produced. These mordants, however, are not employed in practice. A good crimson shade is produced by mordanting silk with alum, and dyeing with an extract of cochineal. In scarlet dyeing, silk is preferably first dyed yellow, then mordanted with "nitromuriate of tin," and finally dyed in a second bath with the assistance of cream of tartar. Silk can also be dyed in a single bath with cochineal, stannous chloride, and oxalic acid.

Cochineal. Technical Preparations of Cochineal.(CHAPTER I. The Anthraquinone Group.)(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.

Ammoniacal Cochineal.

When a solution of carminic acid in ammonia is allowed to stand for some time, there is formed a new compound, which appears to consist of carminic acid in which one of the hydroxyls has been replaced by an amino group. The formula assigned to this substance by Schützenberger was C₉H₉NO₄. This reaction, long known, has been utilised for the production of a new colouring matter termed ammoniacal cochineal, or carminamide, and this comes into commerce either as cakes or in the form of a paste.

The first variety is usually prepared by allowing one part of cochineal to stand in a closed vessel for three months with three parts of ammonia. The clear liquid is decanted, treated with about half its weight of gelatinous alumina, evaporated, and when the mass has become thick, it is cut up into cakes and dried.

The paste is manufactured in a somewhat similar manner, the ammonia, however, being only allowed to react for eight days. The clear liquid is then evaporated to about one-third its bulk without addition of alumina (Crookes, "Dyeing and Calico Printing ").

Ammoniacal cochineal dyes much bluer shades than cochineal itself, and it is sometimes employed in conjunction with the latter. Its use is now very limited, but it finds some application in the blueing of bleached cotton.

Cochineal. The Constitution of Carminic Acid.(CHAPTER I. The Anthraquinone 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.

Nitrococcussic acid was obtained by W. de la Rue from carminic acid by the prolonged action of boiling nitric acid. It was subsequently studied by v. Kostanecki and Niementowski (Ber., 18, 250), and was found to be identical with the trinitrocresotinic acid, of the following constitution: [KUVA PUUTTUU]

When carminic acid dissolved in 50 per cent, acetic acid is treated with an excess of bromine, and the solution digested at the boiling heat, two substances, known as α- and β-bromcarmines, are produced (Will and Leymann, Ber., 18, 3180).

α-Bromcarmine, C₁₀H₄Br₄O₃, the more sparingly soluble substance, crystallises in colourless needles, and melts at 247-248°, with decomposition. When oxidised with potassium permanganate in alkaline solution, it gives dibrommethylhydroxyaldehydrobenzoic acid and dibrommethylhydroxyphthalic anhydride.

On treatment with hot caustic soda solution, a-bromcarmine yields, in addition to a purple-red colouring matter, dibrommethylhydroxyphthalic acid, and bromoform (Miller and Rohde). As a result of this reaction, these authors assigned to α-bromcarmine the constitution of a methylhydroxytetrabromdiketohydrindene for Zincke (Ber., 20, 3227; 21, 2388) had previously shown that dibromdiketohydrindene itself under similar treatment yields both phthalic acid and bromoform.

β-Bromcarmine, C₁₁H₅Br₃O₄, is obtained as a yellow amorphous powder, easily soluble in alcohol (Will and Leymann), and is best purified by means of its potassium salt. Crystallised from acetone, it separates in orange needles, melting at 232° (Will and Leymann) or 288° (Miller and Rohde). By the action of bromine in the presence of 50 per cent, acetic acid solution, it is converted into abromcarmine. As a result of their investigation, Miller and Rohde ascribed to β-bromcarrnine the constitution of a methyldihydroxytribrom-a-naphthaquinone, possessing one of the following formulæ: [KUVA PUUTTUU]

This suggestion was supported by the fact that bromoxynaphthaquinone, on treatment with bromine and caustic soda solution, is converted into dibromdiketohydrindene (Zincke, loc, cit.)

Additional support for this view was obtained by a study of the behaviour of β-bromcarmine with zinc-dust in alcoholic solution. Thus the acetyl compound of the reduction product, melting-point 206°, gave, on analysis, numbers agreeing with those of the acetyl derivative of a methyldibromdihydroxynaphthahydroquinone, possessing the following formula: [KUVA PUUTTUU]

From a consideration of the points above enumerated, Miller and Rohde considered that the constitution of carminic acid could be represented by one or other of the following expressions: [KUVA PUUTTUU]

As, however, such formulæ require C = 64.7 per cent., H = 3.92 per cent., figures which are much higher than those given by the analysis of carminic acid itself, these authors suggested the addition of two molecules of water of hydration, as shown below: [KUVA PUUTTUU]

A substance of this constitution would require C = 55 per cent., and H = 5 per cent.

Somewhat later, Liebermann and Voswinkel (Ber., 30, 688) studied the oxidation of carminic acid with alkaline potassium permanganate at the ordinary temperature, and in this way succeeded in producing two important acids.

Cochenillic acid, C₁₀H₈O₇, crystallises in colourless needles, which melt at 224-225° with evolution of CO₂. It is tribasic, and at 260° is converted into hydroxymethylphthalic anhydride. When heated with water in a sealed tube at 210° it yields symmetrical cresotinic acid and in the same manner at a lower temperature, 170°, gives α-coccinic acid or m-hydroxyuvitic acid. The constitution of cochenillic acid is therefore as follows: [KUVA PUUTTUU]

α-Coccinic acid, C₉H₈O₅, the second product of the oxidation, which, as already indicated, can also be prepared from cochenillic acid, proved to be identical with the hydroxyuvitinic acid of Oppenheim and Pfaff (Ber., 7, 929). It consists of colourless needles, melting-point 239°.

Liebermann (ibid., 30, 1731), whilst agreeing with the diketohydrindene constitution which had been assigned to a-bromcarmine by Miller and Rohde, considered that β-bromcarmine was an indone rather than a naphthoquinone derivative, and could be better represented as follows: [KUVA PUUTTUU]

It was probable, indeed, that carminic acid itself was a hydrindene or bishydrindene derivative, and the following constitutions were at the time suggested for it: [KUVA PUUTTUU]

In a subsequent paper, however, Liebermann and Voswinkel (Ber., 37, 3344) consider that carminic acid is possibly a tetrahydrate of α-dimethyldihydroxynaphthacenequinonedicarboxylic acid and it was observed that the dimethyltetrahydroxynaphthacenequinone prepared by these authors not only possessed weak tinctorial property of a cochineal-like character, but in several respects closely resembled carminic acid itself.

Rohde and Dorfmuller (Ber., 1910, 33, 1363) further examined β-bromo-carmine, and obtained results which support the naphthoquinone constitution assigned to it by Miller and Rohde (loc. cit.), but disprove Liebermann's contention that it is a derivative of indone. By reduction with zinc-dust and acetic acid and subsequent acetylation, β-bromo-carmine gives the compound C₁₇H₁₄O₈Br₂ colourless needles, melting-point 208°C.

Simultaneous hydrolysis and oxidation converts this into the substance [KUVA PUUTTUU] orange prisms, melting-point 258°C.; and it thus appears that by the latter treatment an hydroxyl has entered the quinone nucleus. The diacetyl derivative melts at 233°C. When distilled with zinc-dust, this product, and also β-bromo-carmine itself, give naphthalene.

A valuable contribution to the subject was made by Dimroth (Ber., 1909, 42, 1611), who studied the oxidation of carminic acid with potassium permanganate at 0° in presence of sulphuric acid. The solution thus obtained gave nothing to ether, but on heating for three-quarters of an hour at 90°, it evolved carbon dioxide, and ether then extracted carminazarin.

Carminazarin crystallises from water in garnet-red needles, decomposing at 240-250°. It possesses the constitution, and is very similar to isonaphthazarin.

Its alkaline solution when treated with a stream of oxygen, is quickly decolorised with formation of 5:6-dicarboxy-4-hydroxy-o-tolylglyoxylic acid.

A further point of resemblance of carminazarine to isonaphthazarine is shown by its behaviour with nitric acid in glacial acetic acid, for whereas the latter gives tetraketotetrahydronapthalene, the former yields the analogous Carminazarinquinone crystallising in colourless prisms and which, when heated with water or acetic acid, passes back to carminazarin.

The intermediate product formed by the oxidation of carminic acid with permanganate at 0° insoluble in ether, and which, on heating, is transformed into carminazarin, is termed by Dimroth carminoquinone. The constitutions assigned to this substance and tentatively to carminic acid are given below: [KUVA PUUTTUU]

Carminic acid was, therefore, not a symmetrical compound, and the nature of the group C₁₀H₁₅O₇ was not then determined. At the time, Dimroth considered that the coccinin (see above) of Hlasiwetz and Grabowski, and which is prepared by fusing carminic acid with potassium hydrate, had probably the constitution of a tetrahydroxymethylnaphthalene.

Later, Dimroth (Annalen, 1913, 399, 1) re-examined this product in detail, preparing it by fusing carminic acid with caustic potash at 170-200°C. To it he gave the formula C₁₇H₁₄O₆, and described the pale yellow crystalline tetra-acetyl derivative, C₁₇H₁₀O₆(CH₃CO)₄, melting-point 242-244°C.

When coccinin was oxidised by means of air, or oxygen, in alkaline solution (6 per cent. NaOH), the colour changes above described occurred, and when the pure violet colour had been obtained, acidification with hydrochloric acid yielded a substance coccinone, C₁₇H₁₂O₇, which forms dark brown glistening crystals and decomposes at 250°C.; it yields a tri-acetyl derivative,
C₁₇H₉O₇(CH₃CO)₃,
orange-red crystals, melting-point 210°C., and also ferms three different barium salts (one of which has a composition analogous to the sodium hydrogen salt of 2:6-dihydroxy-8-methyl-a-naphthoquinone-3:5-dicarboxylic acid). Coccinone is reconverted into coccinin by reduction with zinc-dust and ammonia; on the other hand, alkaline oxidation by means of hydrogen peroxide below 20°C. gives rise to two products, cochenillic acid, and an unexamined acid.

Dimroth now formed the opinion that coccinin and coccinone are derivatives of anthranol and anthraquinone respectively, and the position of one of the hydroxy, methyl, and carboxyl groups in coccinone is made clear by the production from it of cochenillic acid. To coccinone Dimroth ascribes the structure [EI KUVAA] and to coccinin either the structure [EI KUVAA].

When heated with water at 200° or dilute sulphuric acid at 170°C. coccinone loses carbon dioxide, yielding decarboxy-coccinone, to which the structure [EI KUVAA] is given; it forms red-brown crystals, and dissolves in alkalis to form purple-red solutions, and in concentrated sulphuric acid with a blue colour which becomes violet on addition of boric acid.

Not only coccinin, but carminic acid itself, has been further examined by Dimroth (loc. cit.), and as a result he considers that this substance is also a derivative of anthraquinone. He has oxidised carminic acid by means of hydrogen peroxide in aqueous caustic soda, using cobalt sulphate as catalyst, and in this way obtained in the first instance carminoquinone, but the reaction proceeded further with the formation, after acidification with 80 per cent, acetic acid, of a yellow crystalline compound, C₂₆H₁₃O₁₆Na₃, 5H₂O, which, when triturated at 0°C. with dilute hydrochloric acid, yielded 2:6-dihydroxy-8-methyl-a-naphthoquinone-3:5-dicarboxylic acid: pale yellow, hygroscopic crystals - trisodium salt, C₁₃H₅O₈Na₃,4H₂O, orange needles.

The orientation of this acid has been established by Dimroth by comparison of its colour reactions with those of 2:6-dihydroxy-α-naphthoquinone, synthetically prepared by Dimroth and Kerkovius, as also by its conversion into carminazarin by treatment with acid permanganate. Moreover, the structure previously assigned by Dimroth to carminazarin, viz. 2:3:6-trihydroxy-8-methyl-α-naphthoquinone-5-carboxylic acid, has been supported by conversion of carminazarin-quinone the oxidation product of carminazarin into a diphenazin, C₂₄H₁₄O₃N₄, by treatment with an alcoholic solution of ο-phenylene-diamine. The product crystallises in yellow needles, and yields an acetyl derivative, C₂₆H₁₆O₄N₄.

When 2:6-dihydroxy-8-methyl-α-naphthoquinone-3:5-dicarboxylic acid the oxidation product of carminic acid referred to above is warmed with water, carbon-dioxide is eliminated with the production of 2:6-dihydroxy-8-methyl-α-naphthoquinone-5-carboxylic acid: brown-yellow needles, potassium salt, C₁₂H₇O₆K, lemon-yellow crystals; dipotassium derivative, C₁₂H₆O₆K₂, orange-red crystals.

This compound when brominated in glacial acetic acid at 40° yields a monobrom derivative, yellow needles, melting-point 240-244°, which on treatment with hydrobromic acid yields α-bromo-carmin, whilst with bromine in cold methyl alcohol, the product is β-bromocarmin (Will and Leymann), which proves that this body has the structure [KUVA PUUTTUU] assigned to it by Miller and Rohde.

Beyond the above-mentioned decomposition products of carminic acid, Dimroth has obtained a 5 per cent, yield of hydrocarbons of the anthracene series by distillation with zinc-dust in an atmosphere of hydrogen. After oxidation of the mixture of hydrocarbons he isolated anthraquinone, and possibly α-methyl-anthraquinone.

By treatment of carminic acid with boiling dilute sulphuric acid, Dimroth has also obtained a 10 per cent, yield of trihydroxy-methylanthraquinone carboxylic acid (C₁₆H₁₀O₇), needles, melting-point above 300°, and this acid when heated with water at 230-240°, passes into trihydroxy-methyl-anthraquinone by loss of carbon dioxide.

Dimroth considered the possibility that the anthraquinone nucleus is produced during the reactions described above, but concluded that this is not the case, and that it is present as such both in carminic acid and coccinin. Dimroth formulates carminic acid thus [KUVA PUUTTUU]

On the other hand, C. and H. Liebermann (Ber., 1914, 47, 1213) bring forward arguments, chiefly the smallness of the yield of anthraquinone or anthracene derivatives obtained by Dimroth, in favour of the view that the anthracene nucleus is formed during the degradation reactions.

These authors have also re-examined the "ruficoccin" of Liebermann and van Dorp (see above), and conclude that it consists of a mixture of trihydroxy-methyl-anthraquinone carboxylic acid, and trihydroxy-methyl-anthraquinone, which is confirmation of the work of Dimroth, Incidentally they described carminic anhydride, C₂₂H₂₀O₁₂, prepared by heating carminic acid with thionyl chloride vivid red powder, resembling carminic acid, though less soluble. It is reconverted into the latter by the action of aqueous alkalis.