Potassium hydroxide salts, extraction

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). 

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. 

Either the iodo carbamate (96) or the iodo amine salt (94) from above can be converted to the aziridine by refluxing about 2.5 g of the respective product in 100 ml of ethanol which contains 10 ml of water and 10 g of potassium hydroxide for ca. 2 hr. The aziridine is then isolated by pouring the basic reaction mixture into 250 ml water and extracting with 200 ml ether. The ether extract is washed several times with water and dried (MgS04). Evaporation of the ether on a steam bath yields 2j5,3j5-iminocholestane (95, 25-95 %) as a clear oil which solidifies on standing mp 103-105°. This aziridine is not easily crystallized. 

This crude product is dissolved in 100 ml of dilute hydrochloric acid, the acid solution is extracted with ether, and the aqueous layer is made basic with sodium hydroxide solution (3N) in the presence of ether (approximately 250 ml). The ether layer Is separated, dried over potassium hydroxide and evaporated to a white solid. Additional purification by repeating the formation of the hydrochloric acid salt and reprecipitation of the base is carried out. When purified in this manner, followed by drying at 80°C in vacuo over phosphorus pentoxide, 2-chloro-11-(4-methyl-1-piperazinyl)dibenz[b,f] [1,4]oxazepine, li/IP 109° to 111°C, is obtained. 

The reaction mixture is removed and about half of the liquid evaporated, an oil separating during the process. The mixture is acidified with concentrated hydrochloric acid and extracted with two 100 cc portions of ether. The extracts, which contain the 5-phenyl-5-(2-thienyOhydantoin, are combined and the combined ether extracts are shaken with two 25 cc portions of 5% potassium hydroxide solution. The alkaline solution, which dissolves the 5-phenvl-5-(2-thienvl)hydantoin to form the potassium salt thereof, is acidifed with hydrochloric acid and heated to expel ether. 

The choice of alkali was more difficult. In Leblanc s time, the alkali was generally a carbonate (C03) or hydroxide (OH) of potassium or sodium extracted from the ashes of salt-rich plants. For example, northerners made an odoriferous soft soap by burning wood and boiling its ashes with animal fat or fish oil. In Spain, Marseilles, Genoa, and Venice, hard Castile soap was made by boiling olive oil with the ashes of seaweed and shore plants. 

The temperature of the potassium hydroxide solution should not he above 35° when used. The submitters report the isolation of 15-20 g. (9-12%) of potassium 1-nitropropylnitronate from the cooled extract. The checkers, having been advised that this product is a hazardous explosive, discarded the warm alkaline extract. If 1,1-dinitropropane is not desired (its preparation has been described 2), it is recommended that it be extracted as its more soluble sodium salt by washing the green oil with sodium hydroxide solution rather than potassium hydroxide solution. 

C. Hydrolysia. Into a three-necked, 5-L, round-bottomed flask equipped with a mechanical stirrer, thermometer, and 500-mL addition funnel with gas Inlet Is placed the above concentrate and 2 L of methanol. The solution is cooled to -5° to 0°C by means of an ice-salt bath. A precooled (0°C) solution containing 220 g of 87.5% potassium hydroxide in 400 raL of water is added dropwise at such a rate as to keep the reaction temperature below 10°C. The reaction mixture is stirred for an additional 2 hr at 0°C and for 1 hr at room temperature prior to the addition of 100 mL of glacial acetic acid. Solid sodium carbonate Is added to bring the pH to 8 and the solution Is filtered through Cellte. Concentration of the filtrate at 35°C and reduced pressure affords about 1 L of a dark liquid. The liquid is diluted with 2 L of water and extracted with petroleum ether (6 x 600 ml). The combined extracts are washed with aqueous sodium thiosulfate solution (800 mL) and dried (magnesium sulfate). Concentration at 30°C affords a clear red liquid (occasionally a yellow solid) which is almost pure internal diester (Note 12). 

Conventional polyether polyol technology involves alkoxylation of the starters with PO and EO using an alkali metal hydroxide catalyst such as potassium hydroxide. The catalyst can be neutralized and the neutral salt can be left in the final polyol, or optionally the catalyst can be extracted by washing with water or by deposition on an ion exchange medium. In recent years, a new catalyst technology has become widely adopted within the polyols industry, using zinc hexacyano-cobaltate (double metal cyanide catalyst, or DMC), which runs at very high... 

Carboxylic acids often have been identified by means of paper chromatography Clarke and Bazill (10) have extracted plasticizers from polyvinyl chloride first with ether and then with methanol. Subsequently the extracts were saponified with alcoholic potassium hydroxide, and the precipitated potassium salts were isolated and converted into free acids. These, in alcoholic solution, were then applied to paper and chromatographed ascendingly with a mixture of butanol, pyridine, water, and ammonia the migration period was about six hours. A number of additional color tests facilitated identification of unknown acids. 

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