Styrax Resinoid

#### Styrax Resinoid. Natural (crude) styrax is so impure that it cannot be used directly in perfumes. It contains substantial amounts of water, and it is a heterogeneous mass which cannot be dispensed without thorough and troublesome stirring. Therefore, only cleaned products, e.g. resinoids, are used in perfumes. A summary of the conventional methods for production of cleaned styrax is given under the monograph **Styrax**. Benzene extraction leads to a true resinoid, free from water and producing a dark olive to brownish colored, very viscous liquid, hardy pourable at room temperature. The resinoid is clearly soluble in most perfume materials, but causes turbidity with alcohol. Direct alcohol extraction leads to a so-called resin-absolute. Water must be removed in order to complete the solution in alcohol. Hot extraction causes severe changes in the composition of the extract (formation of ethyl cinnamate, etc.) while cold extraction and low-temperature evaporation leads to a true-to-nature alcoholic extract of styrax. The alcoholic extract is somewhat darker than the benzene extract, but this depends also upon the quality and type of the styrax. Alcohol extraction of the benzene resinoid leads to a true **Absolute**** ****of**** ****Styrax**. This product is alcohol-soluble, comparatively pale in color, and truly representative of the natural raw material in odor. Petroleum ether extraction yields a pale olive or greenish-brown colored resinoid in a slightly lower yield, but with a sweeter, more balsamic odor. It is available as a "neutralized" (purified) extract, the acids having been removed from the petroleum ether solution by alkali washing prior to evaporation. Benzene extracts are sometimes treated in a similar way. Acetone is now rarely used for extraction of styrax. Like ethyl alcohol, it is miscible with water, and before it can be evaporated without loss of odorous components, the acetone extract must be dried. Direct "extraction" with high-boiling solvents (which are not removed from the "extract"), e. g. diethyl phthalate yields a viscous, diluted extract of styrax, clear and comparatively pale in color, pourable and handy for use. Extraction tests prior to diethyl phthalate addition will tell the manufacturer exactly how much diethyl phthalate he must add to obtain, e.g. a 50% styrax resinoid solution in the diethyl phthalate. Such resinoids should, of course, be duly labelled "**Styrax Resinoid**, 50% solution in D.E.P." and not, as it is often the case: **"Styrax** **"**** **(brand name for this company's resinoids). There is unfortunately no standard prescription for the production of styrax resinoid (or other resinoids), and it is left to the manufacturer's discretion to produce—and to the perfumer's experience to evaluate these products.