Potassium ethylate

CH3CH2)2S. a colourless liquid with an ethereal odour when pure usually it has a strong garlic-like odour b.p. 92°C. Prepared by the action of KHS on ethyl chloride or potassium ethyl sulphate. When heated at 400-500°C it forms thiophene. 

Pure ethyl hydrogen sulphate is difficult to prepare, as it is an oily liquid, very soluble in water, and easily hydrolysed. It is therefore usually isolated as the potassium salt, since potassium ethyl sulphate crystallises well from water, and is not readily hydrolysed in neutral or weakly alkaline solution. 

The solution of potassium ethyl sulphate can be concentrated on the water-bath without appreciable hydrolysis, and the sulphate finally crystallised out-... 

Hydrolysis of Potassium Ethyl Sulphate. Dissolve about i g. of the crystals in about 4 ml. of cold distilled water, and divide the solution into two portions, a) To one portion, add barium chloride solution. If pure potassium ethyl sulphate were used, no precipitate should now form, as barium ethyl sulphate is soluble in water. Actually however, almost all samples of potassium ethyl sulphate contain traces of potassium hydrogen sulphate formed by slight hydrolysis of the ethyl compound during the evaporation of its solution, and barium chloride almost invariably gives a faint precipitate of barium sulphate. b) To the second portion, add 2-3 drops of concentrated hydrochloric acid, and boil the mixture gently for about one minute. Cool, add distilled water if necessary until the solution has its former volume, and then add barium chloride as before. A markedly heavier precipitate of barium sulphate separates. The hydrolysis of the potassium ethyl sulphate is hastened considerably by the presence of the free acid Caustic alkalis have a similar, but not quite so rapid an effect. 

Potassium ethyl xanthate Ethyl S-ethyl xanthate... 

Into a 500 ml. round-bottomed flask, fitted with a reflux condenser, place 42 g. of potassium hydroxide pellets and 120 g. (152 ml.) of absolute ethyl alcohol. Heat under reflux for 1 hour. Allow to cool and decant the liquid from the residual solid into another dry 500 ml. flask add 57 g. (45 ml.) of A.R. carbon dtsulphide slowly and with constant shaking. Filter the resulting almost solid mass, after cooling in ice, on a sintered glass funnel at the pump, and wash it with two 25 ml. portions of ether (sp. gr. 0-720), followed by 25 ml. of anhydrous ether. Dry the potassium ethyl xanthate in a vacuum desiccator over silica gel. The yield is 74 g. If desired, it ma be recrystallised from absolute ethyl alcohol, but this is usually unneceasary. 

Place 32 g. of potassium ethyl xanthate (Section 111,166) and 50 ml. of absolute ethyl alcohol in a 500 ml. round-bottomed flask provided with a double surface condenser. Add 32 g. (16-5 ml.) 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 from a 50 ml. Claisen flask. Collect the ethyl S-ethyl xanthate at 196-198°. The yield is 23 g. 

Fig. 1. Effect of particle size on the flotation recovery of a sulfide mineral. Mineral chalcocite [2112-20-9J, CU2S reagent potassium ethyl xanthate,...

X 10 M sodium oleate 1.5 X 10 M sodium oleate 10 M sodium oleate, pH = 8.1 10 Af potassium ethyl xanthate water... 

The initial hydrolysis of the xanthate in aqueous solutions at room temperature is characterized by the following reaction involving potassium ethyl xanthate ... 

For the manufacturiag of potassium ethyl xanthate, 400% excess of alcohol and equimolar quantities of 50 wt % aqueous potassium hydroxide and carbon disulfide were used (77). After 30 min at 40°C, the mixture was vacuum dmm dried. The product was obtained ia near quantitative yield and assayed at 95%. It is claimed that potassium amyl xanthate can be made with almost the same ratio of reactants and 80 wt % caustic potash (78). 

The described method of preparation of w-nitrophenyl disulfide is essentially that of Foss and co-workers and is a modification of that reported by Ekbom. The disulfide has been prepared by reaction of potassium ethyl xanthate with w-nitrobenzenedi-azonium chloride solution, followed by hydrolysis to yield the mercaptan, which is subsequently oxidized with potassium ferro-cyanide or dilute nitric acid to the disulfide. ... 

To a solution of 2a-bromo-5a-cholestan-3-one (7.1 g, 15.2 mmol) in 175 ml dry acetone is added dropwise a solution of potassium ethyl xanthate (2.6 g, 16.2 mmol) in 90 ml acetone. The reaction mixture is stirred at 20° for 12 hr and then evaporated to dryness under vacuum. The resulting solid is treated with 100 ml hexane to dissolve the organic material and the inorganic salts are removed by filtration. The hexane filtrate is concentrated under vacuum and the resulting yellow solid ca. 7.5 g) is crystallized from chloroform-ethanol to give the xanthate (137) as white needles, ca. 5 g mp 114-115°. 

The potassium ethyl sulphate is filtered and washed with a little spirit or methylated spirit. ... 

In the present instance spirit or methylated spirit (purified) will be found an efficient solvent for potassium ethyl sulphate. The following is the mode of piocedure when a volatile or inflammable solvent is used. the substance is placed in a lound flask attached to an upright condenser and heated on the water-bath. The form of apparatus is that already described (see Fig. 

Before filtering an inflammable liquid such as alcohol the flame must be removed. The potassium ethyl sulphate is dried on a plate of unglazed earthenw are or on a thin pad consisting of three or four sheets of filter paper, with another sheet ovdr the ciystals to keep out the dust. On concentrating the mother liquors on the water-bath, a further quantity of ciystals may be obtained. Yield 35—40 giams. The following equations express the chemical reactions which occur ... 

Potassium Leiuene sulphonate, 177 Potassium ethyl sulphate, 50 Potassium methyl sulphate, 50 Preparations, general remarks, 47 Pressure tube, glass, 24, 78 furnace, 24 metal, 227... 

Figure 4.11 Molecular structures of typical crown-ether complexes with alkali metal cations (a) sodium-water-benzo-I5-crown-5 showing pentagonal-pyramidal coordination of Na by 6 oxygen atoms (b) 18-crown-6-potassium-ethyl acetoacetate enolate showing unsymmelrical coordination of K by 8 oxygen atoms and (c) the RbNCS ion pair coordinated by dibenzo-I8-crown-6 to give seven-fold coordination about Rb.

Diazonium xanthates (ArN—NSCSOC2H5) can detonate, and this procedure should be followed carefully to ensure decomposition of the xanthate as it is formed. Under no circumstances should the diazonium solution and the potassium ethyl xanthate be mixed cold and the mixture subsequently heated. A severe detonation has been reported when such a procedure was employed during the preparation of thiocresol. 

It has been observed2 that the dropwise addition of an aqueous solution of potassium ethyl xanthate to a cold (0°) aqueous solution of diazotized orthanilic acid results in the immediate loss of nitrogen when a trace of nickel ion is present in the stirred diazonium solution.3 The catalyst can be added as nickelous chloride or simply by using a nichrome wire stirrer. When no nickel ion is added and a glass stirrer is employed, the diazonium xanthate precipitates and requires heat (32°) to effect decomposition. 

With potassium ethylate the reaction is complete in twelve hours. 

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