246 ODOROGRAPHIA. 
days in contact with the most concentrated hydrobromic acid, 
phenylbromo-propionic acid is formed, and this is decomposed by 
sodium-carbonate solution with formation of styrolene. A still 
better yield is obtained when phenyliodopropionic acid, which is 
prepared in a similar manner, is boiled with sodium-carbonate 
solution *. 
The artificial, or synthetically prepared styrolene, which was 
termed by Herzog +, who prepared it by distilling cimnamic acid 
with slaked lime, Cinnamol, also the styrolene obtained artifi- 
cially by Berthelot and other chemists, is optically inactive, whilst 
styrolene obtained by distillation from liquid storax is levo- 
rotatory. This appeared remarkable ; but Van t’?Hoff proved that 
the hydrocarbon obtained from storax contains varying quantities 
of an impurity to which it owes its rotatory power f. 
Styrolene chloride is formed by the direct combination of styro- 
lene with chlorine, but it is difficult to purify, since substitution 
products are instantaneously formed. It is a thick oily liquid 
which decomposes on distillation and is scarcely soluble in water, 
but imparts to it a very characteristic penetrating smell, resem- 
bling those of the oils of lemons and juniper berries. 
Styrolene bromide has the same characteristic smell and taste as 
the chloride. It is best obtained by mixing styrolene with an 
equal volume of chloroform § or with two volumes of ether ||, and 
adding the calculated quantity of bromine to the well-cooled 
liquid. It may also be prepared by adding bromine gradually to 
hot ethylbenzene §], and purifying the product by re-crystallization. 
It erystallizes from alcohol in small plates or broad needles 
melting at 74°-74°°5. 
Cinnamic acid occurs in liquid storax, partly in the free state, 
partly as styracim. The uncombined cinnamic acid is easily ex- 
tracted by boiling the drug in water with carbonate of soda or of 
lime. Cinnamate of soda is thereby formed, and can readily be 
decomposed by acids. By this process from 6 to 12 per cent., and 
* Ann. Chem. Pharm. excy. p. 137. 
+ Compt. Rend. lili. p. 523. 
{ Ber. Deutsch. ix. pp. 5 & 1339, and xi. p. 1260; also Ann. Chem. Pharm, 
exli. p. 378. 
§ Ann. Chem. Pharm. cliy. p. 154. 
|| Ibid. cexvi. p. 288. 
4] Ber. Deutsch. chem. Ges. vi. p. 493, and Bull. Soc. Chim, xxxv. p. 55. 
