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Chemistry of Fragrance Ingredients Dr. William L. Schreiber Chemlumina LLC Monmouth University Presented at Fairleigh Dickenson University November 7, 2006 To be discussed • • • • • • • What is a perfume? History Natural Ingredients Synthetic Ingredients Chemical Process Examples Research on New Synthetics The Science of Olfaction What Are Perfumes? Mixtures that are created for use in a wide variety of applications: expensive couturier perfumes, cosmetics, personal grooming products, laundry products, household cleaning products, air fresheners, candles, etc., etc., etc.. From a palette of several thousand materials, most of which are manufactured by chemical processing methods. History of Perfumes 5000 BC – Egyptian First Dynasty – earliest evidence 3000 BC – Mesopotamia: extraction pots, early apparatus 1400 BC – Book of Exodus “anointing with oils” 370 BCE – Theophrastus writings on use of oils to make fragrances longer lasting. 800 AD – Alembic distillation apparatus – Jabir ibn Hayyan 1200 AD – Essential oils produced in pharmacies 1600 AD – Quality of many natural extracts established 1860 AD – 1900 AD – First synthetics (naturally occuring materials) First non-natural synthetics (ionones, nitromusks) Alembic Distillation Appratus What are Fragrance Ingredients? • Odorants, Diluents and Fixatives • Naturals and Synthetics • Chemicals having 6 – 18 carbon atoms (mostly), and usually one oxygenated functional group. There are also some multi-functional materials as well as a few sulfur- and nitrogen-containing chemical compound. What are Fragrance Ingredients? alcohols R OH OH phenolics aldehydes R CHO O ketones R R O esters olefins R O O R O mercaptans amines R SH N Performance in Use • Volatility – Function of molecular weight (how many carbons) and chemical type. • Stability – Function of chemical type and use condition (acidity, alkalinity, oxidizing, open, closed). • Odor Threshold and dose/response – Function of chemical structure (molecular shape and chemical type). Natural Ingredients • Mostly of vegetative origin, a few from animal secretions – largely replaced. • Any part of a plant may be used: flowers, fruits, leaves, twigs, roots, wood. • Synthetics have long overtaken naturals in volume of use. • Naturals still very valuable and provide odor reference points for all materials. Types of Naturals Concretes – extracts with solvent removed Absolutes – concretes re-dissolved and filtered to remove waxes, etc. Essential oils – distillates, often with steam Narcisse Concrete Rose Most important constituents: OH OH citronellol linalool O OH b-phenethyl alcohol b-damascenone Jasmine Most important constituents O O COOCH3 cis-jasmone methyl jasmonate N H indole Patchouli Most important constituents: HO HO HO tricyclic sesquiterpene alcohols Sandalwood • Alpha Santalol: OH • Beta Santalol: OH First Synthetics CH3O O O HO O coumarin vanillin NO2 O O2N methyl ionone gamma NO2 musk xylol Synthesis of Vanillin CH3O CH3O OH- HO HO isoeugenol eugenol (from clove oil) CrVI or MnVII CH3O HO O Synthesis of Coumarin CHO + OH salicylaldehyde O O O KOAc acetic anhydride (Perkin condensation) O O Synthesis of Ionones O O O + OH- 2-butanone citral H3PO4 O alpha-irone O "gamma methyl ionone" Terpene Alcohols from -Pinene HCl Cl beta-pinene 3 myrcene sodium acetate OH- H2 OH citronellol OH OAc geranyl acetate Terpene Alcohols from -Pinene OOH O2 H2 alpha-pinene H2 3 OH OH OH geraniol linalool More Products from -Pinene via Myrcene HO HO * CHO CHO (acrolein) Lyral O * O O H+ Iso E Super O CHO + * Diels - Alder Reactions Sandalwood “Molecular Engineering” • Alpha Santalol: OH • Beta Santalol: OH Synthetic Sandalwoods O peracetic acid alpha-pinene CHO ZnCl2 campholenic aldehyde O CHO O O OH OH H2 Sandalore Bacdanol Musks O O O muscone muskalactone O O2N O NO2 musk ketone Galaxolide Galaxolide Synthesis H + t-amylene a-methylstyrene O (propylene oxide) (CH2O)n, H+ O (paraformaldehyde) OH Newer Musk Synthesis O + OH peroxide catalyst O O OH H+ allyl alcohol cyclododecanone H2O2 O O H2 OH O O O O Cu catalyst Muskalactone Globalide Habanolide Research and Development • Analytical – Application of new gc methods (head space with spme) – Use of more sensitive and better computerized instrumentation: gc-ms, nmr, ftir. • Live flowers – above methods used to analyze odors of flowers before picking. • New extraction methods for naturals: supercritical CO2 Synthetic Research Considerations: • Structure – relationship to materials of known value – natural or synthetic • Raw materials • Process (often a combination of all three) Synthetic Research Practical only for largest companies. • Hundreds of materials synthesized each year for evaluation. • In-depth evaluation must include testing in fragrances and in applications. • Decision to develop cannot be taken lightly. Development of New Synthetics • Processes must be very well worked out in laboratory, pilot plant and factory. • Best economics, safety and workplace hygiene. • Testing is required to meet industry safety standards and international PMN requirements for all new chemicals. • Cost to register new ingredients worldwide is well over $300,000. How We Smell Recent Developments • 1991 – Richard Axel and Linda Buck discover a family of genes that appear to be responsible for olfactory receptors. (received Nobel Prize – 2005) • 1998 – Stuart Firestein expresses a receptor from one of those genes and shows it responds to different odorants. • 2000 – Linda Buck shows that odor perception is based on combinatorial interaction of odorants with receptors. A Code in the Nose Combinatorial Detection A B C D E F 1 2 3 Receptors 4 5 6 7 8 9 350 Receptors: 2350 = 2.3X10105 Combinations 10 …. = Unactivated = Activated In Conclusion… • Fragrance ingredients are a complex part of a the even more complex world of perfumes. Understanding what they are, where they come from and what they do Thank you for the opportunity to is the key to making better smelling and participate in your class this better performing fragrances. evening.