THE JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS This edition is published for THE SOCIETY OF COSMETIC CHEMISTS OF GREAT BRITAIN by Pergamon Press, Ltd. Editorial Office: Ashbourne House, Alberon Gardens, London, N.W.11. Publisher's Office: Headington Hill Hall, Oxford ¸ 1965 Society of Cosmetic Chemists of Great Britain 'VOL. XIV APRIL 19133 4 SYNTHETIC PERFUME MATERIALS FROM PINENE M.P. ERNI* .Presented at the Symposium on Perfumery, organised by the Society, at Cheltenham, Glos., on 14th November 1962. Not only research into unknown odorous principals of natural aromatic :materials retains the attention of the per•umer. New manufacturing routes .of well-established staple perfumery chemicals have also recently aroused ,considerable interest. The economic aspect of one of these new processes, 'the synthesis of certain terpene alcohols from •-pinene, is discussed. The l•urity of these pinene derivatives calls for a new assessment of the odour of the rose alcohols and provides the per•umer with scope for originality. TnE ADWNr of new physico-analytical methods, so fertile in the whole field of chemistry, has also made a deep impact on the industry of synthetic aromatics. Research into the finest ramifications of the immense variety of odorous material which nature offers has greatly progressed. New odorous principals have been isolated, their constitutions established and their syntheses carried out. The perfumer follows this work with a keen interest in the hope that it will result in new, commercially available aromatic chemicals, which he may then use to produce new or better olfactive effects. *A. Boake, l•oberts & Co. Ltd., London, F•.17. 3 163

164 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS But the bulk of a perfume compound still consists mainly of well-knowa synthetic aromatics the chemical constitutions of which are firmly estab- lished. These matehals are produced in large quantities, and demand for the production of these chemicals will expand as more and more everyday retail commodities are making use of odour as a means of sales appeal. Perfumers have a tendency to take the manufacturing processes, the sources of raw materials and the quality specification of these staple aromatics very much for granted. Continuous development is also taking place in this field. The interest of the perfumer has lately been focused on such progress since several fundamental new approaches to manufacturing routes have been made. Probably the most ambitious among these new processes has been the synthesis of geraniol/nerol, and of linalol from myrcene. Since geraniol can be converted into citral, citronellol and citrone!!al, this synthesis gives access to a range of important perfume synthetics traditionally isolated froni natural oils. It also furnishes intermediates for manufacturing hydroxy- citronellal, and the ionones. A long list of distinguished names of all those who have contributed to the work on pinene, myrcene and the terpene alcohols could be mentioned, but particular credit should go to two teams who have developed the industhai processes, and brought them into fruition. Looking for new outlets for turpentine, a group of American research chemists under the direction of Bain effected the industrial production of myrcene from t•-pinene. Subsequently, Bain et al, in particular R. L. Webb, successfully carried out the first industrial synthesis of geraniol from •nyrcene. While the Americans were pressing forward with this project, a British team was studying alternative methods for the production of terpene alcohols and they also found the route from myrcene to be the most pro- ficient. Indeed, under the direction of Carroll, British chemists succeeded in synthesising linalol from myrcene. Thus, while following different objectives, the work of the two groups was complementary. From their joint efforts, highly specialised manufacturing techniques have resulted. In 1957, the first rose alcohols appeared on the market. Whereas nerol was offered from the start in a form containing practically no other rose alcohol, the initial qualities of synthetic geraniol and citronellol were mix- tures of different rose alcohols in order to satisfy the majority of users accustomed to the traditional products. Since 1960, however, increasing quantities of the pure individual alcohols have been produced and their regular sale started this year. In 1958 and 1959, linalyl acetate and linalol ex pinene, made their debut, and in 1961 the first batches of hydroxycitronellal and citral ex pinene, came on the market. It is a salient feature of this development that turpentine