Steam distillation definition

To the cold acid chloride add 175 ml. of pure carbon disulphide, cool in ice, add 30 g, of powdered anhydrous aluminium chloride in one lot, and immediately attach a reflux condenser. When the evolution of hydrogen chloride ceases (about 5 minutes), slowly warm the mixture to the boiling point on a water bath. Reflux for 10 minutes with frequent shaking the reaction is then complete. Cool the reaction mixture to 0°, and decompose the aluminium complex by the cautious addition, with shaking, of 100 g. of crushed ice. Then add 25 ml. of concentrated hydrochloric acid, transfer to a 2 htre round-bottomed flask and steam distil, preferably in the apparatus, depicted in Fig. II, 41, 3 since the a-tetralone is only moderately volatile in steam. The carbon disulphide passes over first, then there is a definite break in the distillation, after whieh the a-tetralone distils completely in about 2 htres of distillate. 

Exceptions to the simple definition of an essential oil are, for example, gadic oil, onion oil, mustard oil, or sweet birch oils, each of which requires enzymatic release of the volatile components before steam distillation. In addition, the physical process of expression, appHed mostly to citms fmits such as orange, lemon, and lime, yields oils that contain from 2—15% nonvolatile material. Some flowers or resinoids obtained by solvent extraction often contain only a small portion of volatile oil, but nevertheless are called essential oils. Several oils are dry-distiUed and also contain a limited amount of volatiles nonetheless they also are labeled essential oils, eg, labdanum oil and balsam oil Pern. The yield of essential oils from plants varies widely. Eor example, nutmegs yield 10—12 wt % of oil, whereas onions yield less than 0.1% after enzymatic development. 

An absolutely scientific definition of the term essential cr volatile oils is hardly possible, but for all practical purposes they may be defined as odoriferous bodies of an oily nature obtained almost exclusively from vegetable sources, generally liquid (sometimes semi-solid or solid) at ordinary temperatures, and volatile without decomposition. This definition must be accepted within the ordinary limitations which are laid down by the common acceptation of the words, which will make themselves apparent in the sequel, and show that no more restricted definition is either advantageous or possible. Many essential oils, for example, are partially decomposed when distilled by themselves, and some even when steam distilled. 

In Preparation 3-8, use is made of a reagent containing 94 % lead tetraacetate and 6 % acetic acid. If the dry, powdered oxidizing agent is used, the reaction solution must be cooled to —40°C or lower before its addition if comparable results are to be obtained. Yields are definitely reduced if the reaction time is prolonged much beyond 10 sec, and if the steam distillation is not completed within a very short time. For this reason this preparation is probably suitable only if small quantities of product are desired. Yields vary from modest to good for the preparation of nitrosobenzene, p-nitrosotoluene, and p-nitroso-chlorobenzene. An attempt to prepare nitrosocyclohexane by this method did not lead to identifiable products. 

Exceptions to the simple definition of an essential oil are, for example, garlic oil, onion oil, mustard oil, or sweet birch oils, each of which requires enzymatic release of the volatile components before steam distillation. In addition, rhe physical process of expression, applied mostly to citrus fruits such as orange, lemon, and lime, yields oils that contain from 2-15% nonvolatile material. 

Essential oil Many definitions exist, referring to the odoriferous and volatile products from natural sources. Usually extracted by expression or steam distillation from a single species, producing an essential oil that corresponds to that species in chemical composition and odour. 

Again, becanse of the potential nnmber of compounds that could exist in a resin mixture, it is difficult to assign a definite strnctnre to any particular resin. However, it is known that the resin colophony (or rosin, the nonvolatile residne from the steam distillation of turpentine) is actually a mixture of resin acids which are derived from the diterpenes. One of the best-known constituents of this mixture is the tricyclic diterpene abietic acid (Figure 3.13). 

Synonyms Amyris balsamifera Amyris balsamifera oil Amyris oil Amyris oil. West Indian type Sandalwood oil Sandalwood oil. West Indian West Indian rosewood oil West Indian sandalwood oil Definition Produced by steam distillation of wood from Amyris balsamifera tree, contg. caryophyllene, cadinene, cadinol Properties Pale-yel. liq. sandalwood odor burning taste sol. in alcohol dens. 0.96 kg/l (20 C) ref. index 1.5035-1.5120(20 C)... 

Definition Oil from steam distillation of Copaifera balsam... 

Definition Oil obtained by steam distillation of leaves from Cinnamomum zeylanicum Properties Lt. to dk. brn. liq., spicy cinnamon, clove odor and taste sol. in oxygenated soivs., fixed oils, propylene glycol, min. oil insol. in glycerin dens. 1.05 kg/l (20 C)... 

Definition Oil from steam distillation of flowering tops and leaves of Salvia sclarea Properties Pale yel. liq., herbaceous odor sol. in fixed oils, min. oil insol. in glycerin, propylene glycol dens. 0.90 kg/l Toxicology LD50 (oral, rat) 5600 mg/kg low toxicity by ing. primary skin irritant TSCA listed... 

Definition Volatile oil obtained by steam distillation of leaves of Eugenia caryophyllus, contg. mostly eugenol... 

Definition Volatile oil from steam distillation of seeds of fennel, Foenicuium vuigane, contg. 50-60% anethole, 20% fenchone, pinene, limonene, dipentene, phellandrene... 

Definition Oil from steam distillation of grasses of Cymbopogon flexosus and Andropogon nardus, contg. citral... 

Definition Volatile oil from steam distillation of fresh Cymbopogon citratus grasses contg. mainly citral... 

Definition Oil derived by steam distillation of herb of Lippia citriodora... 

Definition Volatile oil from steam distillation of fresh root of Levisticum officinale] contains d-a-terpineol, butyl dihydrophthalides, butyl tetrahydrophthalides, coumarin, aldehydes, acetic acid, isovaleric acid... 

Synonyms Fats, nutmeg butter Mace oil Mace oleoresin Macis oil Myristica fragrans Myristica fragrans oil Myristica fragrans oleoresin Nutmeg oil, expressed Definition Volatile oil from steam distillation of dried aril of ripe seed of Myristica fragrans Empirical C7H5CIO... 

Definition Volatile oil from steam distillation of myrrh gum. Commiphora myrrha Properties Lt. brn. to grn. liq. char, odor sol. in fixed oils si. sol. in min. oil insol. in glycerol, propylene glycol... 

Definition Oil derived from steam distillation of the grass, Cymbopogon martini] main constituent is geraniol... 

Definition Volatile oil from steam distillation of Mentha piperita, contg. menthol, and menthyl esters incl. menthyl acetate, and menthone Properties Colorless to pale yel. liq., strong penetrating peppermint odor, pungent taste producing sensation of cold when air is drawn into mouth sol. in 4 vols 90% alcohol very si. sol. in water dens. 0.896-0.908 ref. index 1.460-1.471 (20 C)... 

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