Insoluble liquids steam distillation

Insoluble liquids steam distillation The mutual solubility of some liquids is so small that they can be considered substantially insoluble points K and M (Fig. 9.8) are then for all practical purposes on the vertical axes of these diagrams. This is the case for a mixture such as a hydrocarbon and water, for example. If the liquids are completely insoluble, the vapor pressure of either component cannot be influenced by the presence of the other and each exerts its true vapor pressure at the prevailing temperature. When the sum of the separate vapor pressures equals the total pressure, the mixture boils, and the vapor composition is readily computed, assuming the applicability of the simple gas law,... 

Steam-distillation. Many water-insoluble compounds, both solid and liquid, may be readily purified by distillation in a... 

If the organic compound which is being steam-distilled is freely soluble in water, an aqueous solution will ultimately collect in the receiver F, and the compound must then be isolated by ether extraction, etc. Alternatively, a water-insoluble compound, if liquid, will form a separate layer in F, or if solid, will probably ciystallise in the aqueous distillate. When steam-distilling a solid product, it is sometimes found that the distilled material crystallises in E, and may tend to choke up the condenser, in such cases, the water should be run out of the condenser for a few minutes until the solid material has melted and been carried by the steam down into the receiver. 

Class 4 Steam Distillation. Isolating tars, oils, and other liquid compounds insoluble, or slightly soluble, in water at all temperatures. Usually natural products are steam distilled. They do not have to be liquids at room temperatures (e.g., caffeine, a solid, can be isolated from green tea.). 

On the Theory of Steam Distillation.—The ideal case occurs when the substance to be distilled is insoluble, or, more accurately, sparingly soluble in water (examples toluene, bromobenzene, nitrobenzene) so that the vapour pressures of water and the substance do not affect each other, or hardly so. The case of substances which are miscible with water (alcohol, acetic acid) is quite different and involves the more complicated theory of fractional distillation. Let us consider the first case only and take as our example bromobenzene, which boils at 155°. If we warm this liquid with water, its vapour pressure will rise in the manner shown by its own vapour pressure curve and independently of that of water. Ebullition will begin when the sum of the vapour pressures of the two substances has become equal to the prevailing atmospheric pressure. This is the case, as we can find from the vapour pressure curves, at 95-25° under a pressure of 760 mm. 

A simple apparatus for steam distillation is shown in Fig. 2.102. Flask A contains the liquid to be steam distilled it is fitted with the splash-head B which prevents the carry-over of the contents of the flask A into the receiver. To carry out a steam distillation, the solution (or mixture of the solid with a little water) is placed in the flask A, and the apparatus is completely assembled. Steam is passed into flask A, which is itself heated by means of a flame to prevent too rapid an accumulation of water. If the substance crystallises in the condenser and tends to choke it, the water should be run out of the condenser for a few minutes until the solid material has been melted and carried by the steam into the receiver the water should then be cautiously readmitted to the hot condenser. It is best to use a condenser of the double surface type if the rate at which the steam distillation is carried out is rapid if necessary two such condensers connected in series may be used since in most steam distillations best results are obtained when the process of distillation is carried out rapidly. The passage of steam is continued until no appreciable amount of water-insoluble material is... 

Different products are available from jasmine according to the method of extraction. Solvent extraction gives the concrete use of alcohol, followed by filtration of insoluble waxes, on the concrete separates the absolute and an essential oil is produced by steam distillation of the absolute. The absolute is most commonly used in aromatherapy. It is a viscous orange brown liquid... 

Ambrette Seed Oil occurs as a clear yellow to amber liquid with the strong, musky odor of ambrettolide. It is a volatile oil obtained by steam distillation from the partially dried and crushed seeds of the plant Abeltnoschus moschatus Moench, syn. Hibiscus abeltnoschus L. (Fam. Malvaceae). It is refined by solvent extraction to remove fatty acids or by precipitation of the fatty acid salts. It is soluble in most fixed oils and in mineral oil, often with cloudiness, but relatively insoluble in glycerin and in propylene glycol. 

Amyris Oil, West Indian Type, occurs as a clear, pale yellow, viscous liquid having a distinct odor suggestive of sandalwood. It is the volatile oil obtained by steam distillation from the wood of Amyris balsamifera L. (Fam. Rutaceae). It is soluble in most fixed oils and usually in mineral oil. It is soluble in an equal volume of propylene glycol, the solution often becoming opalescent on further dilution. It is practically insoluble in glycerin. 

Basil Oil, Comoros Type, occurs as a light yellow liquid with a spicy odor. It is obtained by steam distillation of the flowering tops or the entire plant of Ocimum basilicum L. (Fam. Lamiaceae). It may be distinguished from other types, such as basil oil, European type, by its camphoraceous odor and physicochemical constants. It is soluble in most fixed oils and, with turbidity, in mineral oil. One milliliter is soluble in 20 mL of propylene glycol with slight haziness, but it is insoluble in glycerin. 

Birch Tar Oil, Rectified, occurs as a clear, dark brown liquid with a strong leather odor. It is the pyroligneous oil obtained by dry distillation of the bark and the wood of Betula pendula Roth and related species of Betula (Fam. Betulaceae) and rectified by steam distillation. It is soluble in most fixed oils, but it is insoluble in glycerin, in mineral oil, and in propylene glycol. 

Celery Seed Oil occurs as a yellow to green-brown liquid with a pleasant, aromatic odor. It is the volatile oil obtained by steam distillation of the fruit or seed of Apium graveolens L. It is soluble in most fixed oils with the formation of a flocculent precipitate, and in mineral oil with turbidity. It is partly soluble in propylene glycol, but it is insoluble in glycerin. 

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