Clear layer

Place 35 ml. of water in the separatory funnel and run it into the vigoroiisly stirred reaction mixture at such a rate that rapid refluxing occurs. Follow this by a cold solution of 15-5 ml. of concentrated sulphuric acid in 135 ml. of water. Two practically clear layers will now be present in the flask. Decant as much as possible of the ethereal layer A) into a 500 ml. round-bottomed flask. Transfer the remainder, including the aqueous layer, into a separatory funnel wash the residual solid with two 10 ml. portions of ether and combine these washings with the liquid in the separatory funnel. Separate the ethereal portion and combine it with (A). Distil off the ether through an efficient fraction-... 

A theoretical or equihbrium stage is a device or combination of devices that accomplishes the effect of intimately mixing two immiscible liquids until equilibrium concentrations are reached, then physically separating the two phases into clear layers. Crosscurrent extraction (Fig. 15-4) is a cascade, or series of stages, in which the raffinate R from one extraction stage is contacted with additional fresh solvent S in a subsequent stage. 

The viscous magnesium compound formed is cautiously decomposed with dilute acetic acid (75 cc. in 300 cc. of water), the flask being cooled under the tap. Two clear layers are formed, and after separation, the aqueous layer is extracted with 100 cc. of ether, the combined ethereal solution is washed with water and dried with sodium sulfate, and the ether is distilled on the steam bath. The residue is distilled vmder reduced pressure. After a small fore-run the temperature rapidly rises to 130 at 10 mm. when the pure tricarbethoxymethane begins to distil. The yield of material collected over a five-degree interval is 204-215 g. (88-93 per cent of the theoretical amount). The product solidifies at 25°. The melting point of the pure substance is 28-29°. 

A solution of 12.5 g (0.088 mole) of l,4-dioxaspiro[4.5]decane (Chapter 7, Section IX) in 200 ml of anhydrous ether is added to the stirred mixture at a rate so as to maintain a gentle reflux. (Cooling in an ice bath is advisable.) The reaction mixture is then refluxed for 3 hours on a steam bath. Excess hydride is carefully destroyed by the dropwise addition of water (1-2 ml) to the ice-cooled vessel until hydrogen is no longer evolved. Sulfuric acid (100 ml of 10% solution) is now added followed by 40 ml of water, resulting in the formation of two clear layers. The ether layer is separated and the aqueous layer extracted with three 20-ml portions of ether. The combined ethereal extracts are washed with saturated sodium bicarbonate solution followed by saturated sodium chloride solution. The ethereal solution is dried over anhydrous potassium carbonate (20-24 hours), filtered, and concentrated by distillation at atmospheric pressure. The residue is distilled under reduced pressure affording 2-cyclohexyloxy-ethanol as a colorless liquid, bp 96-98°/ 3 mm, 1.4600-1.4610, in about 85% yield. 

If an emulsion has formed, it may be broken by acidifying with hydrochloric acid, whereupon two clear layers are obtained. The benzene solution may be dried and then fractionated or preferably, it may be steam distilled. In the latter case it is transferred to a r-1. Claisen flask, the flask is set in an oil bath (Note 3) and the benzene distilled. Steam is then passed in, and after the last of the benzene is removed, the p-bromodi-phenyl distils with the steam. The temperature of the oil bath is held at 170° in order to hasten the distillation. The product solidifies in the condenser and receiving flask. There is obtained 23-24 g. of -bromodiphenyl which melts at 85-86.5°. 

Clear/impact copolymers, 26 538-540 Clearing layer, in Polaroid SX-70 film, 29 305... 

SYNTHESIS To a vigorously stirred suspension of 18.6 g of 5-bromobourbonal in 100 mLCRjClj there was added 14.2 g methyl iodide, l.Ogdecyltriethylammonium iodide, and 120 mL 5% NaOH. The color was a deep amber, and within 1 min the top phase set up to a solid. This was largely dispersed with the addition of another 50 mL of water. The reaction was allowed to stir for 2 days. The lower phase was washed with H20, and saved. The upper phase was treated with another 100 mL CH2C12, 50 mL of 25% NaOH, another g of decyltriethylammonium iodide, and an additional 50 mL of methyl iodide. The formed solids dispersed by themselves in a few h to produce two relatively clear layers. Stirring was continued for an additional 3 days. The lower phase was separated, washed with H20, and combined with the earlier extract. The solvent was removed under vacuum to give 20.3 g of an amber oil that was distilled at 120-133 °C at 0.4 mm/Hg to yield 15.6 g of 3-bromo-4-methoxy-... 

The slightly moist (cis)-l-[D-3-(benzoylthio)-2-methyl-l-oxopropyl]-4-(phenylthio)-L-proline dicyclohexylamine salt is stirred for 2.5 h in a mixture of 300 ml of ethyl acetate and 200 ml of 10% potassium bisulfate. Two clear layers form. The aqueous layer is extracted with two 200 ml portions of ethyl acetate and the combined organic layers are dried (MgS04). The solvent is removed to yield 10.1 g of foamy solid (cis)-l-[D-3-(benzoylthio)-2-methyl-l-oxopropyl]-4-(phenylthio)-L-proline melting point 42-44°C. 

This N-carbobenzyloxy-cis-4-phenylthio-L-proline cyclohexylamine salt is suspended in 25 ml of ethyl acetate, stirred, and treated with 25 ml of 1 N hydrochloric acid. When two clear layers are obtained, they are separated and the aqueous phase is extracted with additional ethyl acetate (3x25 ml). The combined organic layers are dried (MgS04) and the solvent evaporated to give... 

This l-[D-3-(acetylthio)-2-methyl-l-oxopropyl]-cis-4-phenylthio-L-proline dicyclohexylamine salt is treated with 30 ml of 10% potassium bisulfate and extracted into ethyl acetate, cooled in an ice bath and treating portionwise with 60 ml of 10% potassium bisulfate. The clear layers are separated and the aqueous portion extracted with 60 ml of ethyl acetate (2 times). The organic phases are combined, dried (MgS04), filtered and the solvent is evaporated to give 2.0 g (59%) of glass-like l-[D-3-(acetylthio)-2-methyl-l-oxopropyl]-cis-... 

Overlay Paper. Overlay paper is a-cellulose paper of high purity, with substance weight in the range 20 to 80 g m-2. An essential feature is the refractive index, which is virtually identical with that of melamine-formaldehyde resin hence, after lamination—when all the fibres of the paper are wetted and consolidated with resin devoid of air—the overlay becomes transparent. It forms a durable, hard, clear layer to protect the decorative print layer below. 

A solution of phenylmagnesium bromide is prepared from magnesium (0.54 g, 22 mmol) and bromobenzene (2.20 ml, 21 mmol) in diethyl ether (20 ml). The solution is stirred under reflux as a solution of chalcone (1,3-diphenylpropenone) (2.0 g, 10 mmol) in diethyl ether (15 ml) is added dropwise. The mixture is stirred under reflux for 5 min after the addition is complete, and then allowed to cool. 6M-Hydrochloric acid is added dropwise until two clear layers form. The layers are separated and the aqueous layer is extracted with ether (10 ml). The organic layers are combined, dried (MgS04), and the solvent is evaporated. The residue is recrystallized from methanol (20 ml), to give 1,2,2-triphenylpropan-l-one (1.97 g, 69%), m.p. 92-94°. 

The epidermis consists of five principal layers and is an area of both intense biochemical activity and differentiation. These layers are the stratum comeum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The stratum corneum (horny layer) is the uppermost layer of the epidermis and the skin. The stratum corneum is composed of dead keratinocytes, which are called corneocytes, and has an abundance of keratin and lipid structures [8], The stratum comeum is considered the rate-limiting barrier for the diffusion of chemical compounds across the skin. The stratum lucidum (clear layer) is composed of two to three layers of dead flattened keratinocytes which appear translucent under a microscope and are present only in thick glabrous skin. 

D) Linoleic Acid.—The ester is dissolved in 200 cc. of a 5 per cent alcoholic (Note 21) solution of sodium hydroxide in a 400-cc. beaker and is allowed to saponify overnight at room temperature. The resulting jelly is dissolved in 200 cc. of warm water, and a slow stream of carbon dioxide is introduced, beneath the surface of the liquid, while it is acidified with 50 cc. of dilute sulfuric acid (1 1 by volume). The stream of carbon dioxide is maintained throughout the subsequent operations. The linoleic acid rises to the surface as a clear layer. The water layer is siphoned off the acid is washed once with hot water and then dried over anhydrous sodium sulfate and preserved under carbon dioxide. The yield is 10-12 g. of material having a melting point of —8° to —9° C. (Note 22). 

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