The Coming Shortage Vanilla and Menthol

By now it is clear that vanillin can be made from lignin, but why is synthetic vanillin needed at all The answer is quite simple there isn t enough natural vanillin to go round. The world currently consumes about 12,000 t of vanillin each year, only 18001 of which is produced in vanilla plants (e.g. Vanilla planifolid). Vanilla originates in Central America, and when Heman Cortes conquered the Aztee Empire, vanilla was already in use to flavor chocolate. Vanilla and cocoa arrived together in Europe in 1528 (— 2.22). 

Another favorite substance for medicine and cosmetics is menthol. It is obtained from a number of heibs, peppermint (Mentha x piperita L.) being the most common source (Fig. 2.13). The peppermint plant contains about 1-3 % essential oil, which can be obtained by a chemical separation method called steam distilla-tiom About half of the oil is menthol and its derivatives, terpenes, and flavonoids. Menthol has a pleasant odor and eooling effect, and these two properties are why 

13 Peppermint (A/ew-tiia X piperitaL.) and the simplified strueture of natural ( )-menthol. (Authors own work and eopyright-free Wikipedia pieture) 

Similarly to vanillin, the menthol needs of the world caimot be met from natural sources. However, the synthesis of menthol is less critical, as menthol-producing plants, unlike vanilla, are easy to grow. Synthetic (-)-menthol, identical to the substance found in natural sources but more demanding to produce than vanillin, accounts for about 30 % of the world production, which is 12,0001 a year. 

It is the existence of the eight menthol isomers that makes the chemical synthesis onerous. In many procedures, more than one isomers form as a final product, and needs to be separated out at the end. These byproducts, the isomers of (-)-menthol, all have cooling and refreshing effects, but none of them is as potent as menthol itself. So the presence of these isomers lowers the quality of the final product. Another option is to look for a chemical reaction that produces (-)-menthol exclusively. This was achieved from meta-cresol by the company Haarman and Reimer, which is also a major vanillin producer, whereas a Japanese chemical company, Takasago, 

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