Potassium hydroxide extraction

Chemical tests such as acetone extract, chloroform extract, potassium hydroxide extract, free sulphur, total sulphur and combined sulphur are conducted to find out the ingredients admixed with rubber. Most of the physical and chemical tests and their methods are given in standard specification of ASTM, B S and other national and international specifications. 

Fig. 6.—Quantitative, Precipitin Curves of Rat-liver Glycogen with Con A. (O, Potassium hydroxide-extracted glycogen A, trichloroacetic acid-extracted glycogen , water-extracted glycogen. Con A, 48 /xg of nitrogen. After Ref. 369.)...

The general procedure is similar to that described by Gronowitz5 in the preparation of 3-thiophenethiol, the principal differences being the use of tetrahydrofuran-pentane solvent and the omission of a 10% potassium hydroxide extraction before acidification with sulfuric ac id. This omission leads to higher yields of thiol. 

If only 100 ml. separating-funnels are available, the distillate must be divided into two portions and each extracted with ether as described, the final ether extracts being united for drying with potassium hydroxide. 

Transfer the quinoline chlorozincate to a beaker, add a small quantity of water, and then add 10% sodium hydroxide solution until the initial precipitate of zinc hydroxide completely redissolves, and the free quinoline separates. Transfer the mixture to a separating-funnel, wash out the beaker with ether, adding the washings also to the solution in the funnel, and then extract the quinoline twice with ether. Dry the united ethereal extracts by adding an ample quantity of powdered potassium hydroxide and... 

This type of extraction depends upon the use of a reagent which reacts chemically with the compound to be extracted, and is generally employed either to remove small amounts of impurities in an organic compound or to separate the components of a mixture. Examples of such reagents include dilute (5 per cent.) aqueous sodium or potassium hydroxide solution, 5 or 10 per cent, sodium carbonate solution, saturated sodium bicarbonate solution (ca. 5 per cent.), dilute hydrochloric or sulphuric acid, and concentrated sulphuric acid. 

Benzylatnine. Warm an alcoholic suspension of 118-5 g. of finely-powdered benzyl phthalimide with 25 g. of 100 per cent, hydrazine hydrate (CAUTION corrosive liquid) a white, gelatinous precipitate is produced rapidly. Decompose the latter (when its formation appears complete) by heating with excess of hydrochloric acid on a steam bath. Collect the phthalyl hydrazide which separates by suction filtration, and wash it with a little water. Concentrate the filtrate by distillation to remove alcohol, cool, filter from the small amount of precipitated phthalyl hydrazide, render alkaline with excess of sodium hydroxide solution, and extract the liberated benzylamine with ether. Dry the ethereal solution with potassium hydroxide pellets, remove the solvent (compare Fig. //, 13, 4) on a water bath and finally distil the residue. Collect the benzylamine at 185-187° the 3ueld is 50 g. 

If the atophan does not crystallise—this is rarely the case unless pyruvic acid which has been standing for some time is employed—pour the reaction mixture into a solution of 2a g. of potassium hydroxide in 1 litre of water, and extract the resulting solution two or three times with ether. Place the ether extracts in the ETHER RESIDUES bottle. Treat the aqueous layer with 70 ml. of glacial acetic acid with vigorous stirring. Allow to stand for several hours and collect the crude atophan by filtration with suction. 

Saturate the distillate with sodium chloride (ca. 8 g.) and extract four times with 5 ml. portions of ether. Dry the combined ethereal extracts with a little anhydrous potassium carbonate or a few pellets of potassium hydroxide. Remove the ether (Fig. 11,13, 4), using a 20-25 ml. distilling flask. When all... 

Metal carboxylates are ionic and when the molecular weight isn t too high the sodium and potassium salts of carboxylic acids are soluble m water Carboxylic acids therefore may be extracted from ether solutions into aqueous sodium or potassium hydroxide... 

The aromatic ring of alkylphenols imparts an acidic character to the hydroxyl group the piC of unhindered alkylphenols is 10—11 (2). Alkylphenols unsubstituted in the ortho position dissolve in aqueous caustic. As the carbon number of the alkyl chain increases, the solubihty of the alkah phenolate salt in water decreases, but aqueous caustic extractions of alkylphenols from an organic solution can be accomphshed at elevated temperatures. Bulky ortho substituents reduce the solubihty of the alkah phenolate in water. The term cryptophenol has been used to describe this phenomenon. A 35% solution of potassium hydroxide in methanol (Qaisen s alkah) dissolves such hindered phenols (3). 

A 600-mL, three-necked, round-bottomed flask 1s equipped with a mechanical stirrer, a short gas inlet tube, and an efficient reflux condenser fitted with a potassium hydroxide drying tube. The flask is charged with 13.4 g (0.05 mol) of 3-ben2y1-5-(2-hydroxyethyl)-4-methyl-l,3-th1azol1um chloride (Note 11, 72.1 g (1.0 mol) of butyraldehyde (Note 2). 30.3 g (0.3 mol) of triethylamine (Note 2), and 300 raL of absolute ethanol. A slow stream of nitrogen (Note 3) is begun, and the mixture is stirred and heated In an oil bath at 80°C. After 1.5 hr the reaction mixture is cooled to room temperature and concentrated by rotary evaporation. The residual yellow liquid Is poured Into 500 mL of water contained 1n a separatory funnel, and the flask is rinsed with 150 mL of dichloromethane which is then used to extract the aqueous mixture. The aqueous layer is extracted with a second 150-mL portion of... 

According to the literature, the product obtained in this manner may contain ethyl adipate. To remove this, the product is cooled to 0° and run slowly into 600 cc. of 10 per cent potassium hydroxide solution maintained at 0° with ice-salt. Water is added until the salt which separates has dissolved, and the cold alkaline solution is extracted twice with 200-cc. portions of ether. The alkaline solution, kept at 0°, is run slowly into 900 cc. of 10 per cent acetic acid solution with stirring, the temperature remaining below 1° (ice-salt). The oil which separates is taken up in 400 cc. of ether, and the aqueous solution is extracted with four 250-cc. portions of ether. The ether extract is washed twice with cold 7 per cent sodium carbonate solution and dried over sodium sulfate. After removal of the ether the residue is distilled, b.p. 7g-8i°/3 mm. The recovery is only 80-85 per cent, and in a well-conducted preparation the ethyl adipate eliminated amounts to less than one per cent of the total product. Unless the preparation has proceeded poorly the tedious purification ordinarily is best omitted. 

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