Steam distillation Subject

The flask is then heated in an oil bath maintained at a temperature of 190-210° and the mixture subjected to steam distillation. The sulfonate groups are hydrolyzed in this process and the bromophenol passes over as a heavy, colorless or pale yellow oil. In about one hour the distillate is clear. The product is extracted with ether, the ether is removed by distillation from the steam bath, and the residue is distilled at atmospheric pressure (Note 3). The fraction boiling at 194-200° represents practically pure o-bromophenol. The yield is 70-75 g. (40-44 per cent of the theoretical amount) (Note 4). t -Bromophenol is a colorless liquid with a very characteristic odor. It is rather unstable and decomposes on standing, becoming brown or red in color. 

The alkylborane is then oxidized by the addition of 150 ml of a 15% solution of hydrogen peroxide, while the pH of the reaction mixture is maintained at 7-8 by the simultaneous addition of 3 Asodium hydroxide, the process being carried out at ice-bath temperature. The reaction mixture is neutralized and subjected to steam distillation. The distillate is extracted with ether, and the extract is dried over anhydrous magnesium sulfate. After removal of the ether, distillation yields 18.0 g (70%) of n-octanal, bp 83-85733 mm. 

The mixture was poured in water, acidified to pH 1 with dilute hydrochloric acid, heated on the steam bath for 30 minutes and then subjected to steam distillation to remove the organic solvents. The residue was filtered, dried and recystallized several times from ethyl acetate. The A -19-nor-17a-ethinylandrosten-17/3-ol-3-one thus obtained had a MP of 198° to 200°C (in sulfuric acid bath), 200° to 204°C (Kofler). 

Prepare a mixtime of 40 ml. of concentrated nitric acid and 40 ml. of concentrated sulphiu-ic acid as detailed in the previous Section. Introduce 50 g. of findy-powdered naphthalene in small quantities at a time and with vigorous shaking maintain the temperatime at 45-50° and cool in ice water if necessary. When all the naphthalene has been added, warm the mixtime on a water bath at 55-60° for 30-40 minutes or until the smell of naphthalene has disappeared. Pour the mixture into 500 ml. of cold water the nitronaphthalene will sink to the bottom. Decant the liquid. Boil the solid cake with 200 ml. of water for 20 minutes and pour the water away. Transfer the oil to a large flask and subject it to steam distillation (Fig. II, 40, 1) any imattacked naphthalene will thus be removed. Pour the warm contents of the flask into a beaker containing a large volume of water which is vigorously stirred. Filter ofiF the granulated a-nitro-naphthalene at the pump, press it well, and recrystallise it from dilute alcohol. The yield of a-nitronaphthalene, m.p. 61°, is 60 g. 

If difficulty is experienced in separating the organic layer, the entire solution may be subjected to steam distillation. 

Pure xylan is not employed in industry. but crude xylan or pentosans are of industrial importance. Xylan has been proposed as a textile size but is not employed as yet for this purpose.130 Perhaps the largest use of pentosans is in their conversion to furfural, which has many applications and serves as the source of other furan derivatives. At the present time, large quantities of furfural are used in the extractive purification of petroleum products, and recently a large plant has been constructed to convert furfural by a series of reactions to adipic acid and hexamethylene-diamine, basic ingredients in the synthesis of nylon. In commercial furfural manufacture, rough ground corn cobs are subjected to steam distillation in the presence of hydrochloric acid. As mentioned above, direct preferential hydrolysis of the pentosan in cobs or other pentosan-bearing products could be used for the commercial manufacture of D-xylose. 

To a stirred solution of 10 gm (0.040 mole) of m-iodonitrobenzene in 100 ml of ethanol is added 16 gm (0.30 mole) of potassium hydroxide. The mixture is then heated to reflux for 1 hr. After this, the reaction mixture is subjected to steam distillation. The distillation residue is then extracted with boiling benzene. After cooling, the benzene layer is separated and evaporated to dryness. Yield 5.9 gm (60 %), m.p. (after recrystallization from ethanol-benzene) 120°-121°C. 

In an apparatus set up for steam distillation and containing a rapidly stirred solution of 5.0 gm (0.023 mole) of jV-benzoylphenylhydroxylamine (N-phenylbenzohydroxamic acid) in 100 ml of a 1 1 solution of ethanol-acetic acid, cooled to —20°C, is added 11.5 gm (0.024 mole based on 94% purity) of lead tetraacetate in one portion. After approximately 10 sec (when the initial green color just begins to darken), 100 ml of water is added and the brown or black mixture is rapidly subjected to steam distillation. The distillate is collected in a receiver filled with chopped ice. The product is isolated by filtration of the distillate. Finally, it is dried by pressing dry between filter papers to yield 1.4-2.0 gm (56-80%), m.p. 66°-68°C. 

For recovery of material in the mother liquors, the solutions are subjected to steam distillation to remove solvents and... 

The ether extracts are combined the ether is removed by distillation (Note 12), and the dark red tarry residue subjected to steam distillation. Some 40-50 ml. of distillate is collected after solid quinone no longer appears in the condenser (total volume about 150 ml.). 

The suspension is transferred to a 5-1. three-necked round-bottomed flask and subjected to steam distillation until 7-10 1. are collected (Note 10). The toluene layer is removed, and the aqueous layer is extracted with 1 1. of fresh toluene. The combined toluene layers are agitated for 30 minutes with a solution of 26 g. of sodium bisulfite in 500 ml. of water (Note 11). The toluene layer is washed with water, and the solvent is removed at water-pump pressure on the steam bath. The resulting orange liquid weighs 107-120 g. (65-74%) 1.5250-1.5270, and is... 

To a four-necked round-bottomed flask (2.5 litres) equipped with a reflux condenser, mechanical stirrer, thermometer and nitrogen supply, are added anhydrous toluene (200 ml), p-cresol (108 g, 1.0 mol), tin(iv) chloride (26 g, 0.1 mol) (1) and tributylamine (74 g, 0.4 mol). The mixture is stirred for 20 minutes at room temperature, then paraformaldehyde (66 g) is added. The resulting yellowish solution is heated at 100 +0.5 °C for 8 hours. After cooling, the reaction mixture is poured into water (5 litres), acidified to pH 2 with 2 m hydrochloric acid and extracted with ether. The ether extract is washed with saturated sodium chloride solution, dried over anhydrous sodium sulphate and concentrated to leave the crude product, which is subjected to steam distillation. The final product is obtained in 86 per cent yield, m.p. 55-56 °C. 

Preparation of Hydrazine Dihydrochloride from Benzalazine. One hundred and four grams of benzalazine (0.5 mol) is suspended in 400 ml. of water in a 4-1. round-bottom flask, and 80 ml. of concentrated hydrochloric acid added. The suspension is subjected to- steam distillation until no more benzaldehydef comes over in the distillate. 

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