Potassium Acetate Solution Neutral

Add a few drops of acetic acid and a little ammonium or potassium acetate solution to a moderately strong solution of tartaric acid or a neutral tartrate. On stirring with a glass rod, the acid potassium or ammonium tartrate will be precipitated. 

The crude ketal from the Birch reduction is dissolved in a mixture of 700 ml ethyl acetate, 1260 ml absolute ethanol and 31.5 ml water. To this solution is added 198 ml of 0.01 Mp-toluenesulfonic acid in absolute ethanol. (Methanol cannot be substituted for the ethanol nor can denatured ethanol containing methanol be used. In the presence of methanol, the diethyl ketal forms the mixed methyl ethyl ketal at C-17 and this mixed ketal hydrolyzes at a much slower rate than does the diethyl ketal.) The mixture is stirred at room temperature under nitrogen for 10 min and 56 ml of 10% potassium bicarbonate solution is added to neutralize the toluenesulfonic acid. The organic solvents are removed in a rotary vacuum evaporator and water is added as the organic solvents distill. When all of the organic solvents have been distilled, the granular precipitate of 1,4-dihydroestrone 3- methyl ether is collected on a filter and washed well with cold water. The solid is sucked dry and is dissolved in 800 ml of methyl ethyl ketone. To this solution is added 1600 ml of 1 1 methanol-water mixture and the resulting mixture is cooled in an ice bath for 1 hr. The solid is collected, rinsed with cold methanol-water (1 1), air-dried, and finally dried in a vacuum oven at 60° yield, 71.5 g (81 % based on estrone methyl ether actually carried into the Birch reduction as the ketal) mp 139-141°, reported mp 141-141.5°. The material has an enol ether assay of 99%, a residual aromatics content of 0.6% and a 19-norandrost-5(10)-ene-3,17-dione content of 0.5% (from hydrolysis of the 3-enol ether). It contains less than 0.1 % of 17-ol and only a trace of ketal formed by addition of ethanol to the 3-enol ether. 

A solution of 17-cyanoandrosta-5,16-dien-3jS-ol acetate (46 g) and anhydrous potassium acetate (0.46 g) in methylene dichloride (310 ml) is treated with a mixture of 40% peracetic acid (37 ml) and anhydrous potassium acetate (1.84 g) in methylene dichloride (46 ml), the temperature of the solution being maintained below 25°. The mixture is stored at room temperature for 4 hr and then washed successively with water, 5% sodium bicarbonate solution (aqueous sodium bisulfite, 10g/150g water, has been used to decompose excess reagent before workup) and water until neutral. Evaporation of the dried solution and addition of ether gives 24.1 g of 5oc,6a-epoxy-17-cyanoandrost-16-en-3 -ol acetate mp 187-190°. One recrystallization from methanol gives 20.4 g of oxirane melting at 191-194°. 

Reaction (II) could be the neutralization of acetic acid by potassium hydroxide, yielding potassium acetate which can be isolated in the crystalline state. On dissolution in water the K+ cation is only hydrated in solution but does not participate in a protolytic reaction. In this way, the weak base CH3COO is quantitatively introduced into solution in the absence of an equilibrium amount of the conjugate weak acid CH3COOH. Thus... 

After lysis is complete, the next step can entail the addition of a high-salt neutralization solution, such as potassium acetate. This promotes formation of aggregates of genomic DNA and... 

ESI is a condensed phase ionization process and the ions have to be already present in solution. To generate ions, the pH has to be adjusted in such a tvay that ionizable groups are either protonated or deprotonated. In some cases neutral molecules can be analyzed by the formation of adducts tvith ions such as ammonium, sodium, potassium, acetate or silver. 

Sparingly Soluble Sodium and Potassium Salts. 1. Add several drops of a zinc uranyl acetate solution to 0.5 ml of a neutral solution of a sodium salt. Note the colour of the precipitate. Write the equation of the reaction., ... 

Carbon Disulphide.f — Thoroughly mix 50 cc. of benzene with 50 gin. of alcoholic potassium hydroxide solution (11 gm. of potassium hydroxide in 90 gm. of absolute alcohol), and allow the mixture to stand several hours at a temperature of about 20° C. Shake with about 100 cc. of water, remove the aqueous solution from the benzene, neutralize the latter with acetic acid, and add copper-sulphate solution. No precipitate should form. 

A solution of the 2p,3[3-epoxy-5a-androstan-17-one (30.0 g) in ethanol (130 ml), water (15 ml) and liquid ammonia was heated in an autoclave at 150°C for 6 h and the resultant crystalline suspension evaporated to dryness. Water (35 ml) and acetic acid (36 ml) were added and the solution kept at 90°C for 1 h, cooled and excess water added. The precipitated material was filtered off and the filtrate made alkaline with aqueous 10 N potassium hydroxide solution to precipitate a white solid which was filtered off, washed neutral with water, dissolved in methylene chloride, the solution dried (Na2S04) concentrated and ether added to give 2p-hydroxy-3a-amino-5a-androstan-17-one (14.3 g), melting point I92°-195°C. 

The mixture was then poured into water and acidified with hydrochloric acid. The organic material was extracted with chloroform, the chloroform was exaporated, and the residue stirred for one and 1.5 h with dilute potassium hydroxide solution. Acetic acid was added to make the solution almost neutral, but still slightly basic, the mixture was stirred with activated charcoal for about 15 min, filtered, and the filtrate acidified to Congo red with hydrochloric acid. A crystalline product was obtained upon cooling for several hours, and this was collected by filtration and recrystallized from water giving a-ethyl-m-hydroxycinnamic acid. 

Ammonium hydrogen phosphoramidate (11.4 g., 0.1 mole) is dissolved in 20 ml. of 50% potassium hydroxide solution and warmed to 50-60° for 10 minutes to expel ammonia. The solution is cooled to 5-10°, neutralized to pH 6 (Alkacid test paper) with glacial acetic acid, and treated with 1 1. of ethanol to precipitate the potassium salt which is filtered with suction, washed successively with alcohol and ether, and air-dried. Yield is 8.1 g. (60%). Anal. Calcd. for KHP03NH2 N, 10.37 P, 22.93. Found N, 10.4 P, 22.7. 

Potassium chromate in neutral, acetic acid or ammonia solution yellow precipitate of lead chromate... 

Potassium chloride solution When a concentrated neutral solution of a tartrate is treated with a solution of a potassium salt (e.g. potassium chloride or potassium acetate) and then acidified with acetic acid, a colourless crystalline precipitate of potassium hydrogen tartrate, KH.C4H406, is obtained. The precipitate forms slowly in dilute solutions crystallization is induced by vigorous shaking or by rubbing the walls of the vessel with a glass rod. 

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