Potassium xanthate

Thioacids have a most disagreeable odour and slowly decompose in air. Their boiling points are lower than those of the coiTcsponding oxygen counterparts and they are less soluble in water, but soluble in most organic solvents. An important dithioacid is dithiocarbonic acid (HO—CS2H). Whilst the free acid is unknown, many derivatives have been prepared such as potassium xanthate giving a yellow precipitate of copper xanthate with copper salts ... 

The collector emulsion was more stable when using potassium xanthate instead of sodium xanthate. 

The reagent scheme generally used in these concentrators is presented in Table 19.9. Sodium silicate is used as the common depressant, and also acts as a dispersant together with the soda ash. In the majority of operating plants, Na2S 9H20 is used as the principal activator. Some operating plants in Zambia use NaHS as a sulphidizer. Sodium or potassium xanthates are the principal collectors used, where mercaptans are used as secondary collectors. 

Transformation of 2-deoxysugar derivatives into glycosyl xanthates can be performed by the treatment of O-benzyl-protected hemiacetal derivative with diphe-nylphosphoryl chloride, followed by the reaction with O-ethyl potassium xanthate in the presence of a base (NaOH, PTC reaction or NaH in appropriate organic solvent). High yields and selectivities in such reactions were observed when using sodium hydride in anhydrous THF [401],... 

Potassium 0-(2-propyl) dithiocarbonate can be prepared in the following manner With heating, 42 g (0.75 mol) of potassium hydroxide is dissolved in 400 mL of 2-propanol. The solution is then cooled in an ice bath, and the temperature is kept below 10°C while carbon disulfide (46 mL, 0.75 mol) is added dropwise with stirring. The potassium xanthate is collected by suction filtration and washed with four, 100-mL portions of ether and dried under reduced pressure at ambient temperature yield 111 g (85%). 

Procedure A solution of NH TcO (2 ml) in 0.1 M aqueous ammonia containing Tc ( 10 ppm) is acidified by the addition of 1.5 N HCl (2 ml). To this mixture a 0.5 M freshly prepared aqueous solution of potassium xanthate (1 ml) is added. The mixture is placed in a separatory funnel and mixed by rotating the funnel. Then CCl is added (5 ml) and the mixture is shaken for 20 min. More than 99 % of technetium can be extracted into CCl while rheniiun entirely remains in the aqueous phase. 

Alkyl xanthates (Rxan) of most elements have been known for a long time.1,40 Aryl xanthates have been prepared via potassium xanthate (of 2-substituted phenols only) and thallium aryl xanthates.92... 

Reaction CLV. Action of Potassium Xanthate on Diazonium Compounds with Subsequent Hydrolysis and Oxidation. (E.P., 11865,1892). 

In the presence of potassium hydroxide, cellulose adds to carbon disulfide (Figure 8.4). In this way potassium xanthate A is produced. It is soluble in water, but restores the water-insoluble cellulose upon addition of acid. The primary protonation product is the dithiocarbonic acid O-cellulose ester B. B reacts just like the unstable carbonic acid derivatives in Figure 8.3, namely via a zwitterion (C) and its decomposition into cellulose (a heteroatom nucleophile)... 

A solution of 0.025 mol of sodium or potassium xanthate or dithiocarbamate in 100 ml. of water is added, with stirring, to 3.5 g. of sodium selenopentathionate (0.01 mol) or 4.0 g. of sodium telluropentathionate (0.01 mol) (.synthesis 31) dissolved in 100 ml. of water. The product immediately precipitates, and after being stirred for several minutes, it coagulates, leaving a clear liquid. It is filtered, washed with water and methanol, and dried in vacuo over sulfuric acid. Conditions for crystallization of some of these compounds are outlined in Table I. Selenium ethyl-xanthate, which is an oil, is extracted from the aqueous layer with ether. The ether extract so obtained is dried over anhydrous sodium sulfate, after which the ether is removed by distillation. 

Chlorination of the derivatives (500) with phosphorus oxychloride followed by reaction with ammonia, gives the 2-amino-3-bromopyridines (501). Cyclization of (501 R = 4-pyridyl) was accomplished by heating with ethyl potassium xanthate in l-methyl-2-pyrrolidinone at 160-165 °C to give the thiazolo[4,5-6]pyridine (502 R = 4-pyridyl) in near quantitative yield (Scheme 61) (94JMC248). 

Potassium Xanthate.—C. Schall3 obtained, by the electrolysis of potassium xanthate in aqueous solution and with... 

The spot-test technique, for which the reaction is particularly well adapted, is as follows. Place a drop of the nearly neutral or faintly acid test solution on a spot plate, introduce a minute crystal of potassium xanthate, followed by 2 drops of 2m hydrochloric acid. An intense red-violet colouration is obtained. Sensitivity 0-04 pg Mo. Concentration limit 1 in 250,000. 

Black. Te present. Boil with HC1 to remove dissolved S02 and treat successively with 10 per cent KSCN solution and a little SnCl2 solution. Red colouration, soluble in ether. Mo present. Confirm by potassium xanthate test or by the a-benzoin oxime test. (Section vn.6)... 

May contain undissolved MoS3. Dissolve in concentrated HO and Br2 water, and boil to expel Br2. Test for Mo by the NH4SCN-SnCl2 reaction. May contain As and some of the Mo. Identify As as in Table V. 18 in Section V.12 or by the Gutzeit test (Section III.14). Identify Mo thus acidify a portion of the filtrate with dilute HC1 and add a little solid potassium xanthate. A red-purple colouration confirms Mo. ... 

If the alternative potassium hydroxide method is employed for the separation of Groups IIA and IIB, the KOH extract may contain As, Sb, Sn, Se, Te, and part of the Mo the residue may contain, in addition to HgS, PbS, Bi2S3, CuS, CdS, and PdS, the gold and platinum partly as sulphides and possibly partly in the form of the free metals. Mo is readily identified by the potassium xanthate or a-benzoin oxime test. The Au and Pt will accompany HgS after extraction with dilute nitric acid upon dissolution in aqua regia, Pt may be identified as the dimethylglyoxime complex in the presence of m hydrochloric acid after the Pb, Bi, Cu, and Cd have been removed. 

Potassium xanthate (ethyl potassium xanthate, C2HsO(CS)SK)... 

The potassium xanthate salts of some tertiary alcohols on pyrolysis yield alkenes. The overall yield in this case is often markedly better than those obtained from the corresponding 5-methyl xanthates (the classical Chugaev procedure). 

Larsen EC, Hatcher IF, Adibhatla RM. Effect of tricyclodecan-9-yl potassium xanthate (D609) on phospholipid metabolism and cell death during oxygen-glucose deprivation in PC12 cells. Neuroscience 2007 146 946-961. 

Sodium p-aminophenylarsinate pentahydratc, NH2.CeIl4.AsO(ONa)2. SHjO (82-9 grams), in 200 c.c. of water anti 30 grams of concentrated hydrochloric acid is diazotised at ()" C. and the product slowly poured into a rapidly stirred solution of 20 grams of potassium xanthate, KS.CS.OCaHj, in 420 c.c. of a 10 per cent, solution of hydrated sodium... 

Carboxymethylenethiophenyl-4-arsinicacid,C02H.CH2.S.CgH4. AsO(OH)2.—A diazotised solution of p-aminophenylarsinic acid is added to a solution of potassium xanthate in sodium carbonate at 80 ° C. Sodium hydroxide is then added, and after several hours warming at 90° to 100° C., chloracetic acid and 86 per cent, sodium hydroxide are introduced and tlie solution evaporated to small bulk. The arsinic acid separates on addition of hydrochloric acid. It crystallises from water in pale yellow needles, sintering at 170° C. and melting with decomposition at 187° C. 

In a 1-1. round-bottomed flask equipped with a reflux condenser are placed 157.5 g. (1 mole) of />-chloronitrobenzene, 160 g. (1 mole) of potassium xanthate (Note 1), and 450 ml. of 95% ethanol. This reaction mixture is heated under reflux on a steam bath for 48 hours. The crystalline product, which deposits from solution during the course of the reaction, is collected by filtration, crushed into small particles in a mortar, and washed twice with hot ethanol and once with hot water. The 3neld of />-nitrophenyl sulfide melting at 158-160° is 105-113 g. (76-82%). This product is pure enough for most purposes. Recrystallization from glacial acetic acid (15 ml. per gram) raises the melting point to 160-161°. 

A phosphorus-free striking surface, recommended by Craven, on which any safety-match wilt ignite, is made up as follows —Two parts of a thiocyanate compound, I part of persulphocyanic acid, 0 5 parts of potassium xanthate, 4 parts of antimony sulphide, and as a bindii material, i part of gelatin. 

Osmium complexes, cis- and tnm -Os(S2COR)2(PPh3)2, have been prepared from Os(PPh3)2Br2 and potassium xanthates.228... 

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