Tellurium Chloride Hydroxide

Bis[4-hydroxyphenyl] Tellurium Chloride Hydroxide A mixture of 0.38 g (1 mmol) of bis[4-hydroxyphenyl] tellurium dichloride and 20 ml of distilled water is heated under reflux for 30 min. The solid material is filtered off, washed successively with water and water/acetone (4/1, v/v), and dried over phosphorus pentoxide yield 0.33 g (90%) m.p. 190°... 

Diethyl Tellurium Chloride Hydroxide Diethyl tellurium dichloride is added to an excess of aqueous ammonia and the mixture is carefully heated until the tellurium eompound has dissolved. The solution is then concentrated until the product crystallizes. The product is recrystallized from ethanol. 

Triethyl tellurium chloride,2 (CgHg TeCl, is isolated when an ether solution of tellurium tetrachloride is added dropwise to a similar solution of zinc diethyl. It crystallises from alcohol as colourless plates, M.pt. 174° C., readily soluble in alcohol, sparingly soluble in ether. It is deliquescent in air, and with moist silver oxide gives a hydroxide. 

Tri-p-tolyl tellurium iodide1 melts with decomposition at 232° to 233° C., dissolves readily in methyl alcohol or chloroform, less readily in benzene or ether, and is insoluble in water. Tri-p-tolyl tellurium bromide occurs when the iodide or chloride is boiled with silver bromide. It melts at 265° to 266° C. with decomposition, and dissolves in alcohols or chloroform, but is insoluble in benzene or ether. Tri-p-tolyl tellurium chloride is prepared from the bromide in the usual way. It melts at 260° to 261° C. and gives precipitates with the chlorides of mercury, tin and gold, picric acid and platinic chloride. The hydroxide is a resin, melting at about 110° C., and yielding a pier ate, consisting of long prisms, M.pt. 194° to 195° C.a... 

Tellurium, potassium hydroxide, water, phenylacetylene, a trialkylmethylammonium chloride as phase-transfer catalyst, either tin(IJ) chloride or hydrazine hydrate as reducing agent and toluene as the organic solvent upon heating at approximately 100 for six hours produced Z,Z-bis[2-phenylvinyl ditellurium in low yields. Polytelluride radical anions were postulated as intermediates2 3. 

Bis[2-benzoylphcnyl] Ditellurium [Potassium Hydroxide Method]3 To 200 ml of ethanolic potassium hydroxide are added 16.5 g (48 mmol) of 2-benzoylphenyl tellurium chloride and the mixture is heated until the reddish color disappears and potassium chloride precipitates. The mixture is poured into cold water and the ditellurium compound is extracted with chloroform. The extract is dried, evaporated to dryness, and the residue is recrystallized from benzene yield 12.3 g (83%) m.p. 139°. 

Diphenyl Tellurium Hydroxide Iodide1 Diphenyl tellurium chloride (or bromide) hydroxide is dissolved in water and a slight excess of potassium iodide dissolved in water is added. The yellow precipitate is filtered off and recrystallizcd from methanol. For dissolution of the product in methanol, the mixture is heated cautiously on a water bath to prevent the hydroxide iodide from disproportionating to the diiodide and the dihydroxide (or oxide). The pure product has m.p. 215°... 

Diethyl tellurium hydroxide hydrogen carbonate was formed when the corresponding chloride hydroxide was treated with silver carbonate4. 

Dimethyl Tellurium (Potassium Hydroxide-Tin(II) Chloride Method A mixture of 100 g (1.78 mol) potassium hydroxide and 180/m/ dimethyl sulfoxide is heated on a water bath. After addition of lOg (53 mmol) tin(ll) chloride and 60 g (0.47 mol) tellurium powder, the mixture is heated at 120° for 20 h. The mixture is cooled to 40° and 157 g (1.1 mol) methyl iodide are added dropwise over a period of 2 h. The mixture is then heated at 70° for 2 h and then distilled until the condensing vapor reaches a temperature of 100°. The organic layer of the residue is separated from the aqueous layer. The organic layer is dried and distilled at atmospheric pressure yield 97% b.p. 93-94°. 

The use of sulphur dioxide as precipitant was first proposed by Berzelius, but accurate results by this method are only obtainable under special conditions. Complete precipitation does not take place from a strongly acid solution, and in the presence of other metals small amounts of these are liable to be carried down. In the presence of heavy metals such as copper, bismuth and antimony, the following procedure has been recommended 2 The tellurium is oxidised to telluric acid by the addition of ammonium perdisulphate in the presence of potassium hydroxide, excess of perdisulphate being subsequently removed by boiling. The heavy metals present are next removed by means of hydrogen sulphide. The tellurium may then readily be estimated by reduction with hydrogen chloride and precipitation with sulphurous acid. 

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