Laubenheimer (1872) has shown that probably Benzylic Alcohol, C₇H₈O, boiling at 206° C., likewise occurs in Liquid Storax; it has not been found by Miller. The latter chemist also showed that water removes from the drug a little benzoïc acid; he observed moreover a substance similar to caoutchouc among the constituents of liquid styrax.
There is further to be mentioned as having been met with in Liquid Storax a hydrocarbon, C₈H₈, first prepared by Simon in 1839, which exists in the resin as a liquid, and also in a polymeric form as a solid. The former called Styrol, Cinnamene, or Cinnamol, has a sp. gr. of 0·924, and a boiling point of 146° C. It is a colourless, mobile liquid which may be obtained by distilling with water liquid storax, the odour and burning taste of which it possesses. When heated for a considerable time to 100°, or for a shorter period to 200° C., it is converted without change of composition into the colourless, transparent solid Metastyrol, which, unlike styrol, is not soluble in alcohol or ether. It has a sp. gr. of 1·054, and may be cut with a knife. By prolonged heating, it can be converted into its original liquid form.
Styrol is to be regarded as phenylated ethylene; it can be artificially obtained by shaking powdered cinnamic acid with saturated hydrobromic acid, when crystalline hydrobromated cinnamic acid, C₆H₅·CH₂·CHBr·COOH, is formed. One part of the latter, 10 parts of water, and a little more carbonate of sodium than the quantity required for saturation are mixed. The bromhydrocinnamate of sodium partly splits up immediately, even at 0°, according to the following equation
| C₆H₅·CH₂·CHBr·COONa = | ·CO₂ + NaBr + C₆H₅·CH·CH₂. |
| Bromhydrocinnamate of sodium. | Styrol. |
24 parts of bromhydrocinnamic acid, recrystallized from boiling bisulphide of carbon, yield about 7 parts of styrol; no other method affords as much as this.
Styrol has been discovered in Styrax, but is not regularly, and at all events to a minute amount only, found in the drug of the present day. We have no explanation for the strange fact that it was apparently more abundantly met with in former times.
Lastly there has been found in Liquid Storax, by J. H. van t’Hoff (1876), about 0·4 per cent. of an essential oil, probably C₁₀H₁₆O; Miller also pointed out a compound ether of probably the same (alcoholic) substance as occurring in styrax.
By the action of oxidizing agents, as nitric or chromic acids, or peroxide of lead, the cinnamyl compounds are easily reduced, carbonic acid and water being evolved; and at the same time benzoic acid, bitter almond oil, and hydrocyanic acid are produced. These compounds are in fact abundantly evolved when 6 parts of Liquid Storax are gently warmed with 1 p. of caustic soda, and then mixed with 3 p. of permanganate of potassium dissolved in 20 p. of water.
We have examined several samples of Liquid Storax of average quality, and found by exposure of small quantities to the heat of the steam bath, that it lost from 10 to 20 per cent. of water. The remainder treated with alcohol yielded a residue amounting to 13 to 18 per cent., consisting chiefly of fragments of bark and inorganic impurities. The percentage of the drug soluble in alcohol, to which is due its therapeutic value, thus amounts to 56 to 72. This part, as may be inferred from the foregoing statements, consists chiefly of storesin, the various compound ethers above mentioned, of cinnamic acid and of styracin, no doubt in greatly varying proportions.
Commerce—The annual production of Liquid Storax was estimated by Campbell in 1855 as about 490 cwt. for the districts of Giova and Ullá, and 300 cwt. for those of Marmorizza and Isgengak. The drug is exported in barrels to Constantinople, Smyrna, Syra and Alexandria. Some is also packed with a certain proportion of water in goatskins, and sent either by boats or overland to Smyrna, where it is transferred to barrels and shipped mostly to Trieste.