Organic Chemistry Contributing to Flavours and Fragrances
Background - Why is this important?
The flavour and fragrance industry was estimated to be worth $22 bn in 2010
We encounter perfumes, flavours and fragrances in a very large proportion of the products we come into contact with each and every day such as shampoos, cleaning products and personal fragrances.
However, what are often considered by the public to be ‘perfumes’ are in fact complex mixtures of organic molecules, which may come from natural sources or synthetic routes.
What did the organic chemists do?
Hedione which has been isolated from jasmine oil, is now used in almost all fragrances. In perfume composition, hedione has a blending, fixing and enhancing effect on the other components. It is only really active in its (+)-(cis) form. This is when both substituents are on the same side of the carbon carbon double bond. However, since the 1950's a mixture has been used, where the trans-form dominated i.e. both substituents on opposite sides of the bond.
In 1989, Nippon-Zeon developed an isomerisation process to convert the trans-form into the desirable cis-form, although this only gave about 10% cis. It was not until the mid-1990s, that the first asymmetric synthesis of the desired (1R)-cis-Hedione was achieved. The reaction used a Ru-(-)-(R,R)-Et-DuPHOS catalysed asymmetric hydrogenation as the key step to give the desired cis product. This gives the compound with the correct spatial orientation and the recognisable jasmine odour. Other asymmetric routes to Hedione have since been developed.
Chemists now perform structure-activity relationship studies on perfume ingredients, in much the same as in drug discovery e.g. nerol has a rosy smell but on repositioning of one group, the methyl group, it becomes muguet (lily of the valley).
What is the impact?
The total sales volume of the flavour and fragrance industry in 2010 was estimated to be approximately $22 bn. The industry is truly global and is dominated by 6 international companies who account for 65% of the total market: Givaudan, Firmenich, IFF, Symrise, Takasago and Mane SA.
Also of interest
Sarah Houlton tries to entice us into a career in the flavourings and fragrances industry
‘I enjoy a challenge’, Nathan Lawrence, senior research scientist at Schlumberger Research, tells Emma Davies
Contact and Further Information
Dr Anne Horan
Programme Manager, Life Sciences
Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge, CB4 0WF
Tel: 01223 432699