SOLID ESSENCE OF ANISEED.

637

Solid Essence of Aniseed (C10H120); Sp. gr. of solid 1014; of vapour 5'19; Rel. wt. 74; Fusing pt. 65° (18° C.); Boiling pt. 432° (222° C.).-The crude essence of aniseed contains nearly four-fifths of its weight of this oxidized compound; which may be separated by exposing the oil to a low temperature, submitting the magma to pressure between folds of filtering paper, and crystallizing the residue from hot alcohol (sp. gr. o'850). This substance when treated with chlorine or with bromine yields substitution-compounds.

When essence of aniseed is mixed with concentrated oil of vitriol it is dissolved, and a red solution is formed; on the addition of water, this solution is decomposed, and a substance termed anisoine, isomeric with the solid essence, is precipitated in white resinoid masses. A similar change is produced by treating the

essence with stannic chloride or with antimonious chloride. This modification is insoluble in alcohol, but is soluble in ether and the essential oils: it is rather heavier than water, and is fusible above 212°. The oils of tarragon and of bitter fennel appear each to contain a distinct compound which is isomeric with anisoine and with the solid portion of oil of anise; the principal portion of essence of tarragon consisting of a modification which boils at 403° (2c6° C.), and requires a low temperature for its solidification. These bodies, when oxidized, yield anisic acid, and other products which are identical with those furnished by oil of aniseed. Oil of cumin is also isomeric with the solid essence of anise, but the products of its oxidation are different (1444).

If oil of aniseed be heated in a sealed tube to 430° (221° C.), in contact with a mixture of caustic soda and lime, a small quantity of an acid is formed, which is isomeric with cuminic acid, but not identical with this compound.

The action of nitric acid upon oil of aniseed gives rise to a series of compounds which have been particularly examined by Cahours. They present a close analogy with the compounds of the salicylic series. They may be regarded as containing a radicle termed anisyl (EH ̧‡2), which may be viewed either as a homologue of salicyl, or as a body in which one atom of the hydrogen in salicyl has been displaced by an equivalent of methyl; thus—

8 7

Salicyl.. H ̧(H)→2; Anisyl. Є,H,(CH3)2.

(1465) Anisyl Hydride (EH,,,H); Sp. gr. 109; Boiling pt. about 490° (254° C.).—When oil of aniseed is acted upon by dilute nitric acid, a reddish oil is obtained, consisting of a mixture of anisic acid and anisyl hydride. A quantity of oxalic acid is always formed during its preparation, which may be explained by the following equation :

€ HᎾ + 3 Ꮎ, = €[HᎾ,H + H€ Ꮎ, + H.Ꮎ.

10

3,

7

2 4

If the oil thus obtained be washed with a weak solution of potash, in order to remove anisic acid, and be then cautiously distilled, the hydride passes over in the form of an amber-coloured liquid, which has an aromatic odour resembling that of new hay. Anisyl hydride is homologous with oil of spiræa. It is freely soluble in alcohol and in ether, but insoluble in water. Sulphuric acid dissolves it and forms a dark red liquid, from which on dilution with water the oil is separated unaltered. Anisyl hydride forms crystalline compounds with the acid sulphites of the alkali metals. Indeed, it constitutes the aldehyd of the anisic series.

Anisylic Alcohol (Є ̧H ̧‡,HO); Boiling pt. about 480° (249° C.). -If anisyl hydride be dissolved in an equal volume of alcohol and mixed with three times its volume of a solution of potash (sp. gr. 105) it is decomposed into anisylic alcohol and potassic anisate. The salt crystallizes out, whilst the new alcohol remains in solution; it is decanted and distilled to get rid of the ordinary alcohol; and is then mixed with ether, which dissolves the anisylic alcohol, and leaves it on evaporation as a yellowish oil. This product may be distilled and freed from a trace of anisyl hydride by digestion with hydrosodic sulphite. On redistillation it is obtained as an oil which solidifies when anhydrous at 73° (23° C.), but if it contains water it crystallizes at a lower temperature in hard shining needles; it is heavier than water, and has a feebly spirituous odour and a burning taste. Oxidizing agents, such as dilute nitric acid, gradually convert it into anisyl hydride, and then into anisic acid. Platinum black easily changes it into anisic acid.

Ammonia converts anisyl hydride into anishydramide, 3 ¤ ̧H ̧Ð ̧ + 2 H ̧N = €,II,NO3 + 3 H2O. If anishydramide be maintained for two hours at a temperature of 330° or 340°, it

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3

21 24 2

ANISIC ACID-ANISYL CHLORIDE-ANISOL.

639

fuses and becomes converted into an isomeric base, termed anisine. This body is soluble in alcohol, but scarcely soluble in water or in ether. Its alcoholic solution has a strongly alkaline reaction and a bitter taste; it deposits the alkali in colourless prisms. The salts of this base may be obtained in crystals.

(1466) Anisic Acid (HE,H,, = 152; Fusing pt. 347° (175° C.).—This substance is isomeric with methyl salicylate, and has the composition of a homologue of salicylic acid (p. 632). It may be obtained by boiling oil of anise with nitric acid (of sp. gr. 120); a yellow resinous mass termed dinitraniside [E10H10 (NO2)] is thus formed, and the liquid on cooling deposits long, colourless brilliant prisms of anisic acid. Anisic acid is scarcely soluble in cold water, but is freely soluble in boiling water, in alcohol, and in ether. It may be sublimed unaltered, condensing in white needles; boiling concentrated nitric acid converts it into nitranisic acid (HЄH,NO,,,). The anisates are monobasic; those of the metals of the alkalies and of the earths are soluble and crystallizable but those of lead, silver, and mercury are insoluble in cold water.

Anisyl Chloride [E,H,O,,Cl=1705; Sp. gr. 1261; Boiling pt. 504° (262° C.)] is a colourless oil, of a penetrating, powerful odour; it is procured by distilling anisic acid with phosphoric chloride.

(1467) Anisol (E,H ̧O); Sp. gr. 0'991; Boiling pt. 306° (152° C.). If anisic acid be distilled with an excess of caustic baryta, it yields a compound termed anisol, or phenomethol, whilst baric carbonate remains in the retort :—

6

Anisol has the composition of methyl phenate (CH,,C,H.O). Cahours has obtained it synthetically by decomposing methyl iodide with potassic phenate (1555) :—

Anisol is a colourless liquid of an aromatic odour; it is soluble in water as well as in alcohol and ether. When treated with fuming nitric acid, substitution-compounds are obtained, which may contain 1, 2, or 3 atoms of nitroxyl (NO). Nitranisol (Є,H,,ÑO,,O), when treated with an alcoholic solution of ammonium hydrosulphide, yields a base termed anisidine

2

640

ESSENTIAL OILS WHICH CONTAIN SUlphur.

(Є,H,NO), whilst sulphur is deposited; and if dinitranisol be similarly treated, a nitro-base, nitranisidine, is obtained :

2 [¤‚H ̧(NO2)2O] + 6 H2S = 2[É‚H ̧(NO2)NO] + 4 H2O + 3 §1⁄2. Nitranisidine crystallizes in long brilliant needles, which are of a reddish brown colour: it forms well-defined crystallizable salts with sulphuric, nitric, and hydrochloric acids. If trinitranisol [Є,H,(NO),→] be treated with ammonium hydrosulphide, it yields a third base, dinitranisidine [Є,H,(NO),NO], the salts of which, however, are very unstable, and are decomposed by contact with water. Nitranisidine when treated with the chloride of benzoyl, of cinnamyl, or of cumyl yields a new compound, in which benzoyl, cinnamyl, or cumyl is substituted for hydrogen, and a compound analogous to benzamide is produced; for example :

Nitranisidine.

Benzoyl chloride.

Benzonitranisamide.

¤‚Í ̧‚ÑО„NO + €‚Í ̧‡‚Cl = €,H,‚¤‚H ̧‡‚NO„‚NO + HCl. Experiments of this nature present an interest in connexion with the question of the artificial formation of the natural organic bases; the empirical formula of benzonitranisamide (Є,,H12N,,), presenting considerable resemblance to that of some of the natural alkaloids.

(C.) Essential Oils which contain Sulphur.

141 121

(1468) THE ALLYL SERIES.-The basis of all the oils of the sulphuretted essences which have been accurately examined is the hydrocarbon termed allyl (Є,H). Common garlic (Allium sativum) yields a volatile oil which is a mixture of allyl oxide with allyl sulphide; and the essences of onions and assafœtida, and many of the Asphodeleæ and Cruciferæ, yield similar oils; the essential oils of mustard, of horseradish, and of scurvy-grass consist chiefly of allyl sulphocyanide.

The allyl series has been invested with new interest by the labours of Berthelot and De Luca, who have succeeded in preparing the allyl iodide, or iodized propylene, as they term it, by decomposing glycerin with phosphorus diniodide (1238); a discovery which in the hands of these chemists (Comptes Rendus, Feb. 4, 1856), and in those of Hofmann and Cahours (Ann. de Chimie, III. 1. 432) has led to the formation of numerous derivatives of allyl, and has demonstrated the intimate connexion of these compounds with acrolein and the products of its oxidation.

ALLYL-ALLYLIC ALCOHOL-ALLYL OXIDE.

641

(1469) Allyl (EH)2; Sp. gr. of liquid 0684; of vapour 2'92 ; Rel. wt. 41; Boiling pt. 138° (59° C.).—When allyl iodide is treated with sodium it is decomposed, sodic iodide is formed, and allyl is liberated in the form of a very volatile liquid, possessed of a peculiar penetrating odour, resembling that of radishes. vapour burns with a very luminous flame. It is miscible with sulphuric acid, the mixture being attended with great elevation of temperature, and on standing for a few hours it gradually separates in a modified condition.

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Its

Allyl is immediately attacked by chlorine, bromine, and iodine, with which it forms compounds to which the formula ¤ ̧н ̧¤ ̧; ЄH ̧Br2; and ЄH.I„,, have been assigned. It is, however, probable that these bodies are not true compounds of allyl with two atoms of the halogen, but substitution-products, perhaps of the form ЄHCl,HCl, analogous to Dutch liquid. This point could be ascertained by examining the action of potash upon them.

5"

(1470) Allylic Alcohol (¤ ̧Н¿‚ÍÐ); Boiling pt. 217° (103° C.).— When allyl iodide is digested with oxalate of silver, violent action takes place, double decomposition occurs, in consequence of which allyl oxalate and iodide of silver are produced:

Allyl oxalate, or allyl-oxalic ether, is an aromatic liquid which boils at 404° (207° C.): when treated with ammonia it yields oxamide, and allylic alcohol :

Allyl oxalate.

Allylic alcohol.

Oxamide.

(C,H,),C,O + 2 HẠN = 2 €H HĐ + (HẠN),€0.

2

Ꮎ

Allylic alcohol is metameric with acetone, and with propylic aldehyd, but it differs from them in properties. It is lighter than water, in which it is soluble in all proportions: its vapour is inflammable, and burns with a luminous flame. When treated with potassium, hydrogen is evolved, and potassium-allyl-alcohol (ЄHKO) is obtained in the form of a gelatinous mass.

Allylic alcohol when mixed with sulphuric acid unites with it, and forms allyl-sulphuric acid (HЄ,H,SO), which corresponds with the ethyl-sulphuric. It is the vinic acid of the scries.

3

(1471) Allyl Oxide; Allylic Ether [(Є ̧H.),]; Boils between 185° (85° C.) and 190°.-When the compound of potassium with allylic alcohol is mixed with allyl iodide, violent action occurs; potassic iodide is formed, and allylic ether is produced, by a decom