Potassium iodide-ethanol-water

Table I. Isobaric Vapor-Liquid Equilibrium Data for the Potassium Iodide—Ethanol—Water System at x — 0.309 (758 d= 3 torr)...

Alkali AletalIodides. Potassium iodide [7681-11-0] KI, mol wt 166.02, mp 686°C, 76.45% I, forms colorless cubic crystals, which are soluble in water, ethanol, methanol, and acetone. KI is used in animal feeds, catalysts, photographic chemicals, for sanitation, and for radiation treatment of radiation poisoning resulting from nuclear accidents. Potassium iodide is prepared by reaction of potassium hydroxide and iodine, from HI and KHCO, or by electrolytic processes (107,108). The product is purified by crystallization from water (see also Feeds and feed additives Photography). 

Potassium iodide [7681-11-0] M 166.0, pK -8.56 (for HI). Crystd from distilled water (0.5mL/g) by filtering the near-boiling soln and cooling. To minimise oxidation to iodine, the crystn can be carried out under N2 and the salt is dried under vacuum over P2O5 at 70-100°. Before drying, the crystals can be washed with EtOH or with acetone followed by pet ether. Has also been recrystallised from water/ethanol. After 2 recrystns ACS/USP grade had Li and Sb at <0.02 and <0.01 ppm resp. 

As an example consider the exchange reaction between benzyl iodide and free iodide ions, Eq. (3-43).6 Mixing ethanolic solutions of benzyl iodide and radio-labeled potassium iodide started the isotopic exchange. At different times, samples were withdrawn and added to a benzene-water mixture, causing separation into two layers. The aqueous layer contained the iodide ions, and the organic layer contained the benzyl iodide. The activity of 1311 was determined in each layer. 

Dipping solution Dissolve 250 mg potassium iodide in 25 ml water, mix with a solution of 750 mg starch (soluble starch according to Zulkow-sky) in 25 ml water and dilute with 30 ml ethanol (99.5%) [12]. 

Dipping solution Dissolve 2.8 g potassium iodide and 1.4 g soluble starch according to ZuLKowsKY in 70 ml water and dilute with 30 ml absolute ethanol [10]. 

C. Ethylene Dithiotosylate. To 200 ml. of ethanol containing 10-20 mg. of potassium iodide is added 45.3 g. (0.2 mole) of potassium thiotosylate and 18,8 g. of ethylene dibromide. The mixture is refluxed with stirring for 8 hours in the dark and under a nitrogen atmosphere. The solvent is removed, and the resulting white solid is washed with a mixture of 80 ml. of ethanol and 150 ml. of water. After decantation, the solid is washed three times with 50-ml. portions of water and then recrystallized from approximately 150 ml. of ethanol to yield 28.7 g. of crude product, m.p. 72-75°. Three reerystallizations from a mixture of ethyl acetate and ethanol afford 24 g. (60%) of white crystals, m.p. 75-76° (Note 9). 

N-Acetyl-2,5-dimethoxy-4-iodophenylisopropylamine. 5 g of the diazonium salt is prepared as described immediately above and cooled to 0° then added gradually to a solution of 8 g of potassium iodide in 10 ml of water. After reaching room temp the reaction is set until the evolution of nitrogen has stopped. The dark brown viscous semi-solid that will separate is dissolved in ethanol with heat and then eooled. On cooling the title material separates out and is crystallized from ethanol. Yield 1.97 g, mp 167-168°. 

A sample of 50 ml of V, V-di mcth Iformamide was used to swell chloromethy-lated polystyrene (2.37 g 4.42 mmol Cl per g), and after 30 minutes the material was treated with potassium cyanide (52 mmol) and potassium iodide (1.4 mmol). It was then heated to 60°C overnight during which the resin color changed from whitish to brick red. The resin was then washed consecutively with 20 ml portions of /V, -d i met h I for m am i de, /V, V-d i met h I for m am i de / water, water, ethanol, EtOH, and diethyl ether and the product isolated. 

Cadmium nitrate (4H2O) [10022-68-1 ] M 308.5. Crystd from water (0.5ml/g) by cooling in ice-salt. Cadmium potassium iodide [13601-63-3] M 532.2. Crystd from ethanol by partial evapn. 

TO A SOLUTION OF 1 g POTASSIUM IODIDE IN 5 ml WATER ADD IODINE CRYSTALS TO GET DARK BROWN COLOR. ADD 5 ml ETHANOL. ADD 10% NaOH SOLUTION UNTIL COLOR DISAPPEARS. HEAT GENTLY TWO MINUTES. LET COOL. THE YELLOW PRECIPITATE IS IODOFORM—CHI,. 

O-Ethyl A-ethyl dithiocarbonate. Place 32 g (0.2 mol) of potassium O-ethyl dithiocarbonate and 50 ml of absolute ethanol in a 500-ml round-bottomed flask provided with a double surface condenser. Add 32 g (16.5 ml, 0.205 mol) of ethyl iodide. No reaction appears to take place in the cold. Heat on a water bath for 3 hours a reaction sets in within 15 minutes and the yellow reaction mixture becomes white owing to the separation of potassium iodide. Add about 150 ml of water, separate the lower layer and wash it with water. Dry it with anhydrous calcium chloride or anhydrous calcium sulphate and distil collecting O-ethyl S-ethyl dithiocarbonate at 196-198 °C. The yield is 23 g (77%). 

Triiodobenzoic acid. Dissolve 6.8g (0.0175 mol) of 4-amino-3,5-diiodobenzoic acid (Expt 6.60) in 30 ml of cold concentrated sulphuric acid, add a large excess (3.0 g, 0.0435 mol) of powdered sodium nitrite and allow the mixture to stand at 0°C for 2 hours. Treat the cold diazonium solution with a solution of 17.0g (0.12 mol) of potassium iodide in 40 ml of water a dark red precipitate separates. Warm the mixture on a water bath until evolution of nitrogen ceases, and remove any residual iodine with a little sodium metabisulphite. Filter the yellow precipitate of crude 3,4,5-trii-odobenzoic acid, and recrystallise from dilute ethanol. The yield of pure acid, m.p. 289-290 °C, is 6.8 g (78%). 

Mix together 1.0 g of pure 2-naphthol and the theoretical quantity of 50 per cent potassium hydroxide solution, add 0.5 g of the halide, followed by sufficient rectified spirit to produce a clear solution. For alkyl chlorides, the addition of a little potassium iodide is recommended. Heat the mixture under reflux for 15 minutes, and dissolve any potassium halide by the addition of a few drops of water. The 2-naphthyl ether usually crystallises out on cooling if it does not, dilute the solution with 10 per cent sodium hydroxide solution until precipitation occurs. Dissolve the 2-naphthyl ether in the minimum volume of hot ethanol and add the calculated quantity of picric acid dissolved in hot ethanol. The picrate separates out on cooling. Recrystallise it from rectified spirit. 

Alkyl chlorides often react more rapidly (50-60 minutes) upon adding 0.5 g of potassium iodide to the original reaction mixture, followed by sufficient water or ethanol to produce a clear solution at the boiling point. After refluxing, 0.5 g of picric acid is added, etc. 

A mixture of norcodeine hydrochloride (11.48 g, 27.8 mmol), (chloromethyl)cyclopropane (5.14 g, 55.6 mmol), sodium carbonate (14.73 g, 139.0 mmol), and potassium iodide (4.61 g, 27.8 mmol) in ethanol (250 ml) was heated at reflux for 20 hr, cooled, and evaporated in vacuo to dryness. The residue was basified with NH4OH, and extracted with methylene chloride. The extract was washed with water and evaporated in vacuo to dryness. The residue (11.7 g) was chromatographed on silica gel with a eluting solvent system of methanol/ethyl acetate (10/90) to give 17-cyclopropylmethylnorcodeine (10.68 g, 91% yield). 

Niflumic acid is prepared as follows Nicotinic acid, m-trifluoromethylaniline, and potassium iodide are intimately mixed and heated on an oil bath at 140°C. The mixture melts to give a dark red liquid. The temperature of the oil bath is allowed to fall to 100°C and is maintained at this temperature for an hour and a half. The mixture puffs up and forms a yellow crystalline mass. After cooling to ordinary temperature, this mass is ground up in a mortar and extracted several times with small volumes of ether to remove excess m-trifluoromethylaniline. The residue is then washed twice with 10 ml of distilled water to remove m-trifluoromethylaniline hydrochloride and potassium iodide, and finally twice with 10 ml of 95% alcohol to remove colored resinous contaminants. After drying at 100°C, 2-(m-trifluoromethylanilino)nicotinic acid is obtained as pale yellow needles (from 70% ethanol) melting at 204°C (Kofler block). 

Z-K[Co(enta)] 2H20. The diastereoisomer (2.0 g.) is suspended in 15 ml. of water in a mortar. Four grams of potassium iodide is added and the mixture triturated for 4 to.5 minutes. The insoluble iodide d-[Co(en)2(N02)2]I precipitates and is filtered. Eighteen milliliters of ethanol is added slowly to the filtrate with scratching of the sides of the vessel, and the levo salt separates as sparkling violet plates. This is allowed to stand for 3 or 4 minutes. Then more ethanol is gradually added until a total volume of 40 ml. has been added. The crystals are collected and washed with cold ethanol. Recrystallization is usually not necessary, but may be effected by dissolution in 15 ml. of warm water followed by the addition of 40 ml. of ethanol. The crystals obtained are washed with ethanol and acetone and air-dried. The yield is 1.2 g., or, if the whole of the diastereoisomer is used (2.6 g.), 1.5 g., representing a 75% yield. 

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