Pd-CATALYSED HYDROGENATION OF LIMONENE

摘要

Terpene feedstocks are natural products built up from isoprene units. Many sources of terpenes are thus balsams, natural resins and essential oils, but they are also by-products of lemon and orange juice production, as well as of pulp and paper industries. Some of them, such as (-)-D-pinene and and (+)-limonene are among the more readily available optically active products and therefore used for the synthesis of other optically active products and as reagents for cleaving racemates. Terpenes are very cheap precursors of fragrances, flavors, drugs and agrochemicals. [1] Within the fine chemical industry, they are an important source of intermediates and ingredients for flavours and fragrances. In the perfumery industry, the synthesis of compounds closely related to these natural identical materials led to the discovery of ingredients that are similar in odour, but which are much easier and cheaper to make than their natural counterparts.[2] One of the example is that of jasmine[3]: jasmine absolute (natural) costs $4500- 7000/kg; the natural identical materials-jasmone and methyl jasmine-cost $450-700/kg; and the simpler cyclopentanone derivatives, $15-70/kg. According to Swift [4], the flavour and fragrance industries consume approximately 30000 tons per year of pinene, which are used to produce a diverse range of products. Limonene production is around 30000 tons per year, making it a valuable and renewable feedstock.