408 STYRACE^. 



By distilling the resin of benzoin with ten times its weight of zinc 

 dust, Ciarnician (1878) chiefly obtained toluol, C'^H5(CF^). 



Subjected to dry distillation, benzoin affords as chief product 

 Benzoic Acid, CH'^O^, together with empyreumatic products, among 

 which Berthelot has proved the presence (in Siam benzoin) of Styrol 

 (p. 274-). The latter has been obtained in 1874 by Theegarten from 

 Sumatra benzoe by distilling it with water. When the resin is fused 

 with potash, it is partly decomposed and then, according to Hlasiwetz 

 and Barth (18 GO), yields among other products, protocatechuic acid 

 (more than 5 per cent.), C*'H'(OH)'COOH, para-oxybenzoic acid, 

 C''H\OH)COOH, and pyrocatechin, C^R\OB.y\ 



Benzoic acid exists ready-formed in the drug to the extent of 14 to 

 18 per cent.^ Although the acid dissolves in 12 parts of boiling water, 

 the resin in which it is imbedded precludes its complete extraction by 

 this means. It is however easily accomplished by the aid of an alkali, 

 most advantageously by milk of lime, which does not combine with the 

 amorphous resins. 



Benzoin is not manifestly acted on by bisulphide of carbon, but if 

 kept in contact with it for a month or two, very large colourless crystals 

 of benzoic acid make their appearance. Brought into a warm room, the 

 crystals quickly dissolve, but are easil^^ reproduced by exposure to cold. 



Most pharmacopoeias require not the inodorous acid obtained by a 

 wet process, but that afforded by sublimation, which contains a small 

 amount of fragrant empyreumatic products. The resin, when repeatedly 

 su^ected to sublimation, affords as much as 14 per cent, of benzoic acid. 

 It has Jong been known that the opaque white tears of benzoin are less 

 rich m benzoic acid than the transparent brown resin in which they be. 

 -b rom the latter, S. AV. Brown (1833) extracted 18 per cent, of impure 

 acid, but from the former scarcely SJ per cent. We arc by no means sure 

 that such difference is constant. 



, Bitter almond oil, which by oxidation yields benzoic acid, is wantin| 

 m benzoin. Very little volatile oil is in fact to be got ; half a pound of 

 the best Penang benzoin yielded us by distillation with water only a 

 few drops of an_ extremely fragrant oi\\styrol ?). 



i^ emc chloride imparts to an alcoholic solution of benzoin a dark 

 DiownisH green, which is not acquired under the same circumstances bv 

 tae aqueous decoction of the powdered resin. Benzoin dissolves in cold 

 Oil ot vitriol forming a solution of splendid carmine hue, from which 

 ^vater separates crystals of benzoic acid. 



7nin tn fif ¥y*emann in 18G0 discovered in Siam and Penang ben- 

 Z^ q^f Ir"" ^'^^ ^"'^^'^^^ ''^^^f^' an acid of different constitution, whiA 

 fonn^/ they recogmzed as Ginnamic Acid, C''ffO^ AschofF (1861) 

 Ct 1 1 n"" '^""^^ '^ ?^^^^^^'^ ^^"^«in, cinnamic acid only, of which he 

 benzoin ?o-7'"t ' ^""^ ^^ amygdaloid Siam and Penang benzoin only 

 met w tr^?- ^^^^"^?;^ample? of the latter, one of us (F.) has likewise 

 Sid WW ♦r"''? f ^^- ^^ triturating this sort with peroxide of lead 

 to the o^li ' "^f^^'^ ^^^^^ ^ater, tlie%dour of bittei^almond oil, due 



The sit.U " '^ '^^^""^^^ ^^^iJ' i« ^^^olved. , . , 



simultaneous occurrence of benzoic and cinnamic acids, or the 



tempS't J S-e "iht fv"^^- 1^^'^^^ ^*- they have not shown Avith which substance 



present in the fom of . ^"'^ '^ P^^*^y '* is combined in the drug. 



lorm of a compound, but 



