Fragrance Materials

Several manuals devoted, at least in part, to flavor formulation have been published (52—63), eg, literature from the Fragrance Materials Association of the United States, Washington, D.C. The increasing number of materials available has resulted in the improvement of flavor characteristics and has permitted a closer rendition of natural flavors. Often such materials bear a scant sensory relationship to the tme natural flavor character. When used as a component and judiciously applied, these materials serve a useful purpose in a properly compounded flavor. 

Specifications also appear in other pubHcations, including pubHcations of the Fragrance Materials Association (FMA) of the United States (53,57) (see also Fine chemicals). The FMA specifications include essential oils, natural flavor and fragrance materials, aromatic chemicals, isolates, general tests, spectra, suggested apparatus, and revisions adopted by the FMA. 

Liquid Fabric Softeners. The principal functions of fabric softeners are to minimize the problem of static electricity and to keep fabrics soft (see Antistatic agents). In these laundry additives, the fragrance must reinforce the sense of softness that is the desired result of their use. Most fabric softeners have a pH of about 3.5, which limits the materials that can be used in the fragrances. For example, acetals cannot be used because they break down and cause malodor problems in addition, there is the likelihood of discoloration from Schiff bases, oakmoss extracts, and some specialty chemicals. Testing of fragrance materials in product bases should take place under accelerated aging conditions (eg, 40°C in plastic bottles) to check for odor stabiUty and discoloration. 

Rearrangement of dehydrolinalool (4) using vanadate catalysts produces citral (5), an intermediate for Vitamin A synthesis as well as an important flavor and fragrance material (37). Isomerization of the dehydrolinalyl acetate (6) in the presence of copper salts in acetic acid followed by saponification of the acetate also gives citral (38,39). Further improvement in the catalyst system has greatly improved the yield to 85—90% (40,41). 

Pyrolysis of the i j -pinane produces dihydromyrcene (24) (citroneUene) as the major product in 50—60% yield. Fractionation of the cmde product then gives an 87 wt % dihydromyrcene (57). Dihydromyrceno1 (25) produced from the dihydromyrcene is becoming increasingly important as a fragrance material. It has excellent stabiUty and has a powerhil, fresh, lime-like aroma. Hydration of citroneUene using formic acid has become an important commercial method for producing dihydromyrcenol (58). 

The production of myrcene (7) from P-pinene is important commercially for the synthesis of a wide variety of flavor and fragrance materials. Some of those include nerol and geraniol, citroneUol (27) and citral (5). 

Epoxidation of diliydromyrcenol gives an iatemiediate epoxide that can be hydrogenated to hydroxycitronellol. Treatment of the diol with acid can also give the a-,P-citroneUol and the a-citroneUol can be isomerized to the P-citroneUol (27) (110). The diol, hydroxycitronellol, is also useful for produciag hydroxycitroneUal, a lily-of-the-valley fragrance material. 

Ionones and Methyl Ionones Manufacture. The discovery of ionones and methyhonones was an early example of the need to develop synthetic fragrance materials because of the high cost of natural materials. The aroma of violet flowers was important to perfumery and led to the development of ionones and methyhonones at the end of the nineteenth century. 

Important commercial sesquiterpenes mosdy come from essential oils, for example, cedrene and cedrol from cedarwood oil. Many sesquiterpene hydrocarbons and alcohols are important in perfumery as well as being raw materials for synthesis of new fragrance materials. There are probably over 3000 sesquiterpenes that have been isolated and identified in nature. 

Because PEA is such an important fragrance material this simple, essentially one-step process has been exhaustively studied to optimize reaction conditions and purification procedures. Because of the high reactivity of the iatermediates and the tendency toward polymer formation, critical factors such as throughput, temperature, molar ratios of reactants, addition rates, reactor materials and design, and agitation rate must be carefully balanced to provide an economical product with acceptable odor properties. 

Flavor and Fragrance Materials, Flavors and Extracts Manufacturers Association, 1989. 

Flavor and Fragrance Materials—1991, AHured Publishing Corp., Wheaton, HI., 1991. 

Broekhof NLJM, Hofma J. J., Renes H., Sell C. S. A New Variant of the Diels-Alder Reaction and Its Use in the Synthesis of Fragrance Materials Perfum. Flavor. 1992 77 11-12 14... 

The Research Institute on Fragrance Materials maintains the most comprehensive worldwide source database on fragrance/flavour components including acute aquatic toxicity, biodegradation data, human health issues, for example, carcinogenesis, sensitization. A password is required to access the database. 

Sampling Wastewater Treatment Plants for Fragrance Materials. 92... 

Mechanisms of Fragrance Material Removal During Wastewater Treatment. . 95... 

Keywords Fragrance materials Wastewater treatment Polycyclic musks Nitromusks Abbreviations... 

Fragrance material CAS number MW (g mob1) log ow Ki (L kg-1) Water solubility (mg L-1) Vapor pressure (Pa) Henry s law constant (Pa m3 mol-1) Biodegradability... 

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