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.

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