Isolating Methods
Soxhletting the root bark of cinnamomum camphora (camphor laurel), or probably parts of other plants (see below) with distilled ethanol, or hexane and chloroform, yields most of the available safrole, and is cheap and effective. The solvents can be evaporated off or reclaimed by distillation.
Dealing with the impurities in the soxhlet extract is another matter. Steam distillation from bulk plant material is also reported to work.
Refinement methods from oil
Cool the oil or the safrole-containing fraction of the oil, to at least -12°C. Safrole will crystallise.
Use fractional distillation, followed by cooling and crystallisation. Regarding the distillation of safrole in mixtures consult Brauer, Ber Schimmel & Co, Jubil?ms-Ausgabe (1929), 153.
Where safrole may be contaminated by oily constituents in an essential oil as in red camphor oil, the method of Ikeda and Takeda (a) may be employed advantageously to determine the safrole by reparation of the addition product with mercuric acetate and sodium chloride in dilute acetone. The precipitate so formed should be filtered in a Gooch funnel and weighed, and used with a correction factor to define the percentage of safrole in the sample. This complex hydroxychloride of safrole [C10H10O2(OH)HgCl] according to Tsukamoto (b) is readily decomposed to regenerate safrole either by sodium sulfide and zinc in potassium hydroxide; or hydrochloric acid. The oxychloride melts at 141-142°C according to Fujita (c).
