Ethyl xanthate

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... 

Other Inorganic Compounds. Alkali—metal and ammonium teUuropentathionates (Te(S203)2), have been prepared. The S2O3 group can be replaced by ethyl xanthate or diethyl dithiocyanate. 

Fig. 1. Solubihty of some commercial xanthates. (—), Sodium isobutyl xanthate (-), sodium ethyl xanthate (—...

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

Further hydrolysis of the carbon disulfide and the trithiocarbonate produces hydrogen sulfide, etc (33). In another study of the decomposition of sodium ethyl xanthate [140-90-9] in flotation solutions, eleven components of breakdown were studied. The dependence of concentration of those components vs time was examined by solving a set of differential equations (34). 

Where no water is present, very pure xanthates form (65). Ethanol reacts slowly with sodium trithiocarbonate to produce sodium 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 most important hazard ia the manufacturiag of xanthates is the use of carbon disulfide (qv) because of its low flash poiat, ignition temperature, and its toxicity. A report on the manufacture of sodium ethyl xanthate at Keimecott Nevada Mines Division discusses the various safety problems and the design of a faciUty (81). A plant layout and a description of the reagent preparations are also given. 

Because of hydrate formation, the sodium salts tend to be difficult to dry. Excess water over that of hydration is beheved to accelerate the decomposition of the xanthate salts. The effect of heat on the dryiag of sodium ethyl xanthate at 50°C has been studied (84) ... 

Xanthate dmms should be kept as cool and dry as possible. Protection from moisture is the most important factor. A combination of moisture and hot weather causes sodium ethyl xanthate to ignite spontaneously (14). 

Pyridazines form complexes with iodine, iodine monochloride, bromine, nickel(II) ethyl xanthate, iron carbonyls, iron carbonyl and triphenylphosphine, boron trihalides, silver salts, mercury(I) salts, iridium and ruthenium salts, chromium carbonyl and transition metals, and pentammine complexes of osmium(II) and osmium(III) (79ACS(A)125). Pyridazine N- oxide and its methyl and phenyl substituted derivatives form copper complexes (78TL1979). 

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°. 

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. 

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