Preparation, of essential oils

As would be expected with products of such diverse character, the methods employed for the preparation of essential oils vary considerably. Broadly speaking, however, the processes may be divided into three classes—(1) expression, used for orange, lemon, and linui oils (2) distillation, employed for otto of rose, geranium, sandalwood, and many other oils and (3) extraction, including cnfleuraije, by which the volatile oil from the flowers is either first absorbed by a neu-... 

Ukita K, Murakami T. Preparation of essential oils loaded granule by melt granulation. Drug Dev Ind Pharm 1994 20(6) 981 992. 

Basil is another Lamiaceae herb primarily used for culinary purposes and it is grown in subtropical regions all over the world with nearly 150 different species. However, different cultures have traditionally used basil as a means to treat warts, constipation, kidney malfunctions, bronchitis, and sore throats (Javanmardi et al 2003 Vieira and Simon 2000). Evaluations of secondary metabolites in basil have revealed an array of phytochemicals that include monoterpenes, sesquiterpenes, and aromatic compounds (Juliani and Simon 2002). Ethanolic extracts and preparation of essential oils from a variety of basil species were shown to have high antioxidant properties in vitro (Juliani and Simon... 

Emulsions of fatty- and petroleum-based substances, both oils and waxes, of the o/w type are made by using blends of sorbitan fatty esters and their poly(oxyethylene) derivatives. Mixtures of poly(oxyethylene(20)) sorbitan monostearate (Polysorbate 60) and sorbitan monostearate are typical examples of blends used for lotions and creams. Both sorbitan fatty acid esters and their poly(oxyethylene) derivatives are particularly advantageous in cosmetic uses because of their very low skin irritant properties. Sorbitan fatty ester emulsifiers for w/o emulsions of mineral oil are used in hair preparations of both the lotion and cream type. Poly(oxyethylene(20)) sorbitan monolaurate is useflil in shampoo formulations (see Hairpreparations). Poly(oxyethylene) sorbitan surfactants are also used for solubilization of essential oils in the preparation of colognes and after-shave lotions. 

Essential Oils. Volatile oils from plants are referred to as essential oils. The oils can be obtained through steam distillation, solvent extraction, or separation of the oils from pressed fmit. They consist of oxygenated compounds, terpenes, and sesquiterpenes. The primary flavor components of essential oils are oxygenated compounds. Terpenes contain some flavors but are often removed from the essential oil because they are easily oxidized (causiag off-flavors or odors) and are iasoluble. Essential oils are prepared from fmits, herbs, roots, and spices. 

Bodies of an alcholic nature play a very important part in both natural and synthetic perfumery. They are found to a very large extent in essential oils, both in the free state and also in the form of esters. Some that have not so far been recognised as constituents of essential oils, have been found to be so highly odorous, and so useful as perfume materials, that they are prepared artificially, and enter largely into the composition of the synthetic perfumes which to-day are indispensable to the manufacturer of perfumes. It is obvious that those alcohols which are soluble in water, such as methyl and ethyl alcohols, although they may be original constituents of some essential oils, are removed by the ordinary distillation processes, so that they do not, in fact, appear in the essential oil as found in commerce. 

The higher aliphatic alcohols, from octyl alcohol upwards, have-recently been introduced as perfume materials with considerable success. Only one or two of them, such as nonyl and undeeylenic alcohols, have so far been detected as natural constituents of essential oils, but other members of the series are prepared artificially, and are employed in minute quantities in the preparation of perfumes with characteristic, fruity bouquets. These alcohols are greatly diminished in perfume value by traces of impurities. According to H. J. Prins, the first interesting member of the series is octyl alcohol it has a very sweet, rose-like odour, and is especially suitable for giving a rose perfume that pecnliar sweet smell which distinguishes a rose from a rose perfume. This feature of the aliphatic alcohols diminishes in the series from Cg to Cjg. 

This acid, of the formula CgHgCH CHCOOH, occurs in a number of, essential oils in the free state. It is prepared artificially by heating benzal chloride with sodium acetate. It has a sweet odour. It is a crystalline substance, melting at 133° and boiling at 300°. 

CO2 extraction has been prevalent for the isolation of essential oils and other natural lipophilic pigments like carotenoids. Hot water and superheated water extraction methods are used for analytical preparation of polar pigments. The technique is commonly referred to as subcritical water extraction because the practitioners of this approach come from SEE backgrounds. 

Eugenol is a natural product available from a variety of essential oils (cinnamon-tree or pimentos leaves). Its isomerization (Eq. 49) into isoeugenol, the starting material for synthetic vanillin, is rather difficult and proceeds in modest yields under relatively harsh conditions. It can, however, be very efficiently prepared by use of 2.2 molar equivalents of base and catalytic (5 %) amounts of Aliquat in the absence of solvent. 

The patent and proprietary medicines of fixed dose combinations of essential oils with alcohol having percentage higher than 20% proof except preparations given in the Indian Pharmacopoeia. 

Synthesis of (+)- and ( )-Citronellol from the Citronellal Fraction of Essential Oils. (+)-Citronellal is obtained by distillation of Java citronella oil and is hydrogenated to (+)-citronellol in the presence of a catalyst (e.g., Raney nickel). Similarly, (zb)-citronellol is prepared from the ( )-citronellal fraction of Eucalyptus citriodora oil. 

Capillary gas chromatography (GC) using modified cyclodextrins as chiral stationary phases is the preferred method for the separation of volatile enantiomers. Fused-silica capillary columns coated with several alkyl or aryl a-cyclo-dextrin, -cyclodextrin and y-cyclodextrin derivatives are suitable to separate most of the volatile chiral compounds. Multidimensional GC (MDGC)-mass spectrometry (MS) allows the separation of essential oil components on an achiral normal phase column and through heart-cutting techniques, the separated components are led to a chiral column for enantiomeric separation. The mass detector ensures the correct identification of the separated components [73]. Preparative chiral GC is suitable for the isolation of enantiomers [5, 73]. 

Cologne and other Fragrant Waters.—These preparations are mostly solutions of bouquets of essential oils, or extracts, in alcohol, improved by distillation. For common kinds distillation is omitted. 

The number of essential oils which are obtained from flowers, fruits, peel, leaves and secretions of different plants or are prepared synthetically, is very large. Some are, however, of little commercial interest, whilst others are of great importance, especially in certain regions. In the following pages, attention is paid chiefly to the oils of the add fruits (orange, lemon, etc.), the characters of other oils being dealt with in Table XXXIV. 

Camphor has been determined by Baines and Proctor (183) in a number of essential oils and pharmaceutical preparations using gas chromatographic technique. The apparatus employed has a thermal conductivity detector with 1+ in. platinum wire 0.001 in. diameter of nominal resistance 250 Ohms. The wires in the channels being matched to within 0.1 Ohm. The bridge current was 200 mA and the output recorded on a 2.5 mV recorder. 2% ethylbenzene was added to the standards and samples as an internal standard. The operating conditions were as... 

The bark of C. cassia is a tonic, stomachic and carminative. The bark is useful in inflammation, headache and piles. C. cassia bark and its essential oil are used in various medicinal preparations. The essential oil from the stem bark and cinnamaldehyde regulates the triggering of hepatic drug-metabolizing enzymes by the formation of a glutathione-conjugate (Choi et al., 2001). The bark exhibits promising anticancerous and antitumour activities. 

The substances that are used to transport the essential oils into the body are called carriers. Carriers include a range of substances such as the air when inhaling, water in a bath and all the lotions, creams, shampoos and other products that are used to apply preparations containing essential oils to the skin. 

MSDS - Material Safety Data Sheets (now usually referred to as SDS, Safety Data Sheets) Suppliers, manufacturers and importers who make up the chain of supply of essential oils to the aromatherapist, and ultimately the client, are responsible for drawing up the MSDS. Each time an oil is repackaged or relabelled, a MSDS should be prepared and relevant additional... 

Citrus oil dominates this class of essential oil. It is obtained by the cold press method with the exception of lime oil, which is also prepared by steam distillation of essential oil separated during the production of juice.106,107 Aside from bergamot, these oils are primarily monoterpene hydrocarbon mixtures of which (if)-limonene (3) is usually the dominant compound. Since odor contribution of this monoterpene compound is low, it is often removed by distillation or repeated solvent extraction. The resulting oil rich in odor-active compounds is called terpeneless oil and is used extensively. In the case of bergamot and lemon oils, psoralen derivates like bergaptene (64) causing photosensitivity are problematic, and those for fragrance use are rectified to remove it (Table 8). 

Phenylethyl alcohol is prepared by reduction of ethyl phenyl-acetate with sodium in absolute alcohol by hydrogenation of phenylacetaldehyde in the presence of a nickel catalyst or by addition of ethylene oxide or ethylene chlorohydrin to phenylmagnesium bromide, followed by hydrolysis. Phenylethyl alcohol also occurs naturally in a number of essential oils, especially rose oil. 

Huang L-H, Qin T-F, and Ohira Tatsuro (2004) Studies on preparations and analysis of essential oil from Chinese fir. Journal of Forestry Research, 75(1) 80-2 Hudson MS and Henrrksson ST (1956) The oscillation pressure method of wood impregnation. Forest Products Journal, 6(10) 381-6 Hughes C (1982) The natural durability of untreated timbers. What s New in Forest Research No. 112. New Zealand Ministry of Forestry, Forest Research Institute, Rotorua Humphrey PE and Bolton AJ (1989) The hot pressing of dry-formed wood-hased composites. Part 2 A simulation model for heat and moisture transfer, and typical results. Holzforschung, 43 T) 199-206... 

Supercritical fluid extraction has been applied to plants and food samples with different objectives. Regarding plants, it has been applied for the extraction of active compounds used in the elaboration of pharmaceutical preparations or for the extraction of essential oils, widely used in the pharmaceutical industry as well. In the former case, SFE has been used as a suitable tool for the monitoring of dosage levels of drugs administrated to animals through their feeds and also for the extraction of active compounds from food, thus allowing characterization of some properties of the food such as the vitamin content. 

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