SALICYL. 



SALICYLIC GROUP. 



250 



facture of carbonate of soda, of which it contains about 15 per 

 cent. 



SALICYL. [SALICYLIC GROUP.] 



SALICYLAMIDE. [SALICYLIC GROUP.] 



SALICYLIC ACID. [SALICYLIC GROUP.] 



SALICYLIC GROUP. A cluster of chemical substances, compounds 

 or derivatives of the electro-negative radical salicyl (C 14 H 5 O,). The 

 members of this group itself a subdivision of the benzoic series in 

 Gerhardt's arrangement are numerous ; including the odoriferous oil 

 "i meadow-sweet and of winter-green, and the bitter principle of 

 willow-bark. 



Salicyl (C,,H,O 4 ) itself has not yet been isolated. Ag it contains 

 the elements of phenyl (C,.H S ) and carbonic acid (C,0 4 ), and as, more- 

 its compounds are not unfrequently converted into bodies 

 identical with derivatives of phenyl, the salicylic group has sometimes 

 been termed the phenyl-carbonic group. 



'/lide of benz'jyt (C,,H 5 O 4 , C 14 H S 0,), paraialicyt, or tpirlnt, is 

 obtained by acting upon chloride of benzoyl with hydride of salicyl, or 

 from the destructive distillation of salicylide of copper. It is insoluble 

 in water, soluble in alcohol or ether, crystallises in prisms, melts at 

 260, and sublimes at 356 Fahr., and is converted into picric acid on 

 being boiled with nitric acid. 



//-'/,-,./, ,,f lalicyl <C 14 H,0 4 , H); lalicylnta acid ; tpiroiu acid, or 

 esmtial oil nf >/iiraa utmaria. Besides the method of obtaining this 

 body from the flowers of incadow-sweet, as described under ESSKXTIAL 

 OILS, it maybe produced by decomposing salicin under the influence 

 of oxidising agents. According to Buchner, such an operation is simply 

 an imitation of what occurs naturally in the ipinra flowers ; the buds 

 plant contain salicin, and have scarcely any smell ; but, on 



Salicin. 



C M H Oj + C ia II M O 14 



Saligenin. Glucose. 



expanding freely expose their parts to the air, when oxidation of the 

 naliciu goes on, and hydride of salicyl results, giving odour to the 

 Bowcn. The artificial oxidation of salicin is conveniently effected by 

 biehroBttto of potash. To two parts of salicin, two of bichromate of 

 potash, and sixteen of water, in a retort, are added three of oil of 

 vitriol, previously diluted with eight parts of water. After a short 

 time a gentle heat may be applied, when the oil passes over ; twenty- 

 five parts of salicin yielding six of the essence. The salicin for this 

 process need not be pure ; indeed, aqueous extract of willow-bark serves 

 very well. 



When quite pure, hydride of salicyl is a colourless oil, but from 

 contact of air soon acquires a red hue. It has an agreeable aromatic 

 "l"ur, acrid taste, boiling point 360 Fahr., specific gravity M73, 

 rapour density 4'276, and burns with a bright smoky flame. It is 

 somewhat soluble in water, the solution giving a deep violet colour 

 with peraalts of iron. Hydride of salicyl is an acid body : it decomposes 

 the alkaline carbonates with effervescence, and combines with bases 

 generally to form neutral and acid talicylida. The potassium salts 



contain respectively K,C H.O. + 2 Aq. and K,C,,H.O 4 + H,C 14 H,0 4 . 

 CUonMtjtm arid (C,.(H,C1)O.,H), bromwlicylom add (C. (H 

 I'.i .< i.. H), i'xtotalicyloiu acid, and hydride of nitnmlicyl (C U (H,M > \ 

 ' >,. 1 1 1, are respectively produced by the action of chlorine, bromine, 

 .and nitric cid upon hydride of salicyl. They are crystalline 

 uni In, and form crystalline salts with Imncs 



Xalhydramiilc, ialir,//imide, or hydride of aiotalieyl (C 41 H 1 ,N.O. I ) is 

 the product of the action of ammonia upon hydride of salicyl : 



C,,H,0 4 



JSH, = 



6HO 





Hydride of Ammonia. Salhydrunide. u . , 



fieri. 



It crystallises in prisms, is insoluble in water, slightly soluble in cold 

 .il li.il, and more so in hot alcohol. 



Cldontamide (C..H 1 ,CLN,O,), or the hydride of chlorazosalicyl, and 

 bromanmide (C^HjS-Jr.OJ or the hydride of bromazoaalicyl, are 

 formed on acting with ammonia upon the chlorine and bromine 

 derivatives of hydride of salicyl. 



Thi,Milir,J (<-',. H.0,8,), or hydride of sulphosalicyl, is a pulverulent 

 substance, formed on treating salhydramide with sulphuretted hydrogen. 



Rjfttrtm deriralint of hydride of salicyl, and of the preceding 

 "indii of salicyl, result from the action of sulphurous acid upon 

 th.-.r alkaline salts, or of the alkaline bisulphites upon the compounds 

 th'-rn - 1-. -. 



,So/; (C M H,,0 14 ) is a neutral bitter principle contained in the bark 

 >f tli.' various species of willow and poplar (sallow, osier, aspen, AcA 

 It readily crystallises out from a concentrated decoction of the bark, 

 after tannic acid and colouring matter have been removed by hydrated 

 oxide of lead. 



When pure, salicin occurs in white silky crystals, soluble in water or 

 in alcohol, but insoluble in ether or oil of turpentine. It melts at 

 ' Fahr., loses water at 392* Fahr., and at a higher temperature 

 decomposes. Concentrated sulphuric acid communicates a blood red 

 colour to it; the liquid, neutralised with chalk, yields a deliquescent 

 chestnut, brown powder, containing, according to Mulder, ulphurufie 

 arid. Water decomposes the red body formed by sulphuric acid; 

 heat, also, gives rise to the formation of a resinoid body, that has been 

 called by one chemist olirin, by onother rutUin, while a third thinks it 

 to be latirrtin. .Several chlorine derivatives of salicin exist. 



fa/iyrnin (C,.H,O,) and grape sugar result from the action of boiline 

 dilute acids IIJK.II salicin : 



Hence sahcm is one of the glucosides. Saligeniu crystallises in 

 colourless crystals very soluble in boiling Nvater, alcohol, OP 

 ether It is partially volatile ; most oxidising agents convert it into 

 hydride of salicyl, while chlorine gives rise to trichlorophenic acid 



Saliretin (C.^O,) is a product of the action of heat upon sali K enin 

 in closed vessels; it is also produced by prolonged ebullition of 

 sahgemn with dilute acids. It is a white or yellow-coloured resinoid 

 body, mso.uble in water or in ammonia, but soluble in alcohol ether 

 or concentrated acetic acid. 



Ifelicia (2 (C,.H,.0 14 ) + 3aq.) is obtained on digesting salicin in 

 ten times its weight of nitric acid of specific gravity 1-160 for about a 

 day : hydrogen is thus removed from the salicin, water being formed 

 and helicin deposited in acicular crystals. It is inodorous, of slightly 

 'itter taste, very soluble in boiling water or alcohol, but almost 

 insoluble in ether. Chlorine and bromine act upon, and give rise to 

 derivatives of, helicin. 



Helicnidin (C 52 H S4 0. S + 3aq.) seems to be a combination of heliciu 

 and sahcm (C H 3 .O = C H 10 14 + C M H 18 O U ). It is produced 

 i the oxidation of sahcm by nitric acid is incomplete, or when the 

 specific gravity of the acid is less than that above indicated. 



Populin (CtH. f (0 M H.OJO t , + 4aq.). or salicin in which an equiva- 

 lent of hydrogen is replaced by benzoyl, has already been described 



; [POPULIW.] 



Conmarin, a fragrant principle of several plants, seems to be allied 

 to the members of the salicylic group, inasmuch as it yields salicylate 

 of potash when fused with the hydrate of that base. It is further 

 described in a separate article. [COUMARIN.] 



Salicylic acid (HO,C M HLO.l In combination with methyl this 

 acid exists naturally in oil of wintergreen. [ESSKNTIAL OILS.] On 

 boiling the oil for a few minutes with solution of potash, neutralising 

 by hydrochloric acid, and allowing the mixture to cool gradually 

 salicylic acid crystallises out in acicular tufts. Salicylic acid may also' 

 formed by projecting salicin, in small portions at a time, into 

 hydrate of potash fused in a silver basin, the temperature not being 



owed to rise higher than 750 Fahr. On dissolving the mass in 

 water and adding hydrochloric acid, the salicylic acid is precipitated, 

 and may be purified by recryatallisation from boiling water. 



Salicylic acid fuses at 316 Fahr., and at a higher temperature 



bhmes unchanged. It is soluble in alcohol, ether, or oil of turpen- 

 tine. A mixture of peroxide of manganese and sulphuric acid oxidises 

 it to formic acid. By ebullition with nitric acid it is converted first into 

 nitrosalicylic acid and, finally, into picric acid. Distilled with excess 

 of lime it is split up into carbonic and phenic acids. Its solutions 

 give an inky-blue precipitate with persalts of iron, the colour disap- 

 pearing on the addition of hydrochloric acid. 



Salicylic acid decomposes carbonates with effervescence, and forms 

 tnlicylate* that are, for the most part, monobasic and crystalline The 

 potash salt contains (KO,C,.H S O 5 , aq.) ; the double salicylate of cupper 

 andpotatk has the formula KO,C 14 j "j } O s + 4aq. : it crystallises in 

 be.iutiful emerald green plates. 



Salicylic ethert. Although the oil of wintergreen appears to be a 

 definite salicylate of methyl (C,H,O, C 14 H S O 5 ), it nevertheless plays the 

 part of an acid, and from its source has been termed GauUheric acid: 

 it still admits of the replacement of an equivalent of hydrogen by a 

 metal or a radical, yault/urato being formed ; thus : 



Oaulthcratc of iiotMh . . . KO, C, 4 H,(C 1 H.,)O. ; 

 Oaoltherate of methyl . . . C.II.,0. C^^C.Il'.JO. 



But this gaultheric acid or hydrate of methyl-salicyl admits of the 

 substitution of an acid radical for hydrogen, and thus are formed : 



Benzoate of mcthyl-alicyl . . . c i H (C,H,)O, J 

 Cumlnatc of mcthyl.jalicyl . . . c H i( c i H )O I 



Similarly the ethyl-gaultheric acid, or rather hydrate of ethyl-salicyl 

 and the amyl-gaultheric acid, or hydrate of amyl-salicyl, on being acted 

 upon by the chloride of benzoyl yields : 



Benzoate of cthyUalicyl . . . c i4H,(C,H,)O, ) 

 Benzoate of unyl-ralicyl . . . . "i^(C|eH, ,)O S ) 



Chlorine and bromine derivative! of salicylic acid result from the 

 action of chlorine and bromine on salicylic acid. Their formula! are : 



Chloroealicylic acid 

 Bichlorosalicj lie acid 

 Bromosalicylic acid 

 Hibromosalicylic acid 

 Tribromosalicyllc acid 



. c, 4 n, cio. 



C 14 H 4 C1,0. 

 . C 14 H 5 BrO r , 

 . C 14 H 4 Br,0. 

 . C 1 ,H s Br,O b 



