From Sodium Tellurite

Sodium tellurite dissolved in aqueous sulfuric acid reacted with a methanolic solution of the dithiocarbamic acid to produce the corresponding bis[tris(dithiocarbamato)tellurium] oxide  

Irgolic Organo-tellurium Compounds without a C,Te-Bond 

Bis[tris(iV-niethyl-A -2-hydroxyethyldithiocarbamato)tellurium] Oxide 0.44 g (2 mmol) of sodium tellurite are dissolved in 20 ml of water, 5 ml concentrated sulfuric acid and then 50 mmol of AT-ethyl-lV-2-hydroxyethyldithiocarbamic acid in methanol are added. The mixture is stirred until the red solution deposits yellow crystals. The mixture is filtered, the crystals are washed with water, methanol, and acetone, and dried over anhydrous calcium chloride yield 1.1 g (90%) m.p. 165  

Reactions carried out under similar conditions with dimethyl-, diethyl-, pentamethylene-, bis[2-hydroxycthyl]-, or 3-oxapentamethylenedithiocarbamic acid yielded tellurium tetrakis[dithiocarbamatcs] and not the expected bis[tris(dithiocarbamato)tellurium] oxides.  

The compound is insoluble in all solvents but reacts with hydrohalic acids to form tellurium tris[dithiocarbamate] halides.  

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Tellurium bis[thiolobenzoate] was obtained from sodium tellurite and thiobenzoic acid in strongly acidic medium. The compound was recrystallized from benzene. A single-crystal X-ray structural analyses showed the thiolobenzoate groups to be bidentate2. 

Solutions of sodium tellurite in water1,2 or prepared from tellurium dioxide and aqueous sodium hydroxide3 were acidified with sulfuric acid and treated with freshly prepared solutions of bis[2-hydroxyethyl]dithiocarbamic acid in aqueous methanol. Addition of aqueous solutions of potassium chloride, iodide, or thiocyanate led to the deposition of crystalline tris[bis(2-hydroxyethyl)dithiocarbamate] halides. 

Tellurium Bis[bis(2-hydroxyethyl)dithiocarbamate] Diiodide1 20 ml (2 mmol) of a 0.1 molar aqueous solution of sodium tellurite are acidified with 40 ml of 1 normal sulfuric acid and 40 ml of 20% aqueous methanol containing 20 mmol of bis[2-hydroxyethyl]dithiocarbamic acid are added. A dark-red liquid separates. Aqueous methanol is decanted from the dark-red liquid, 20 ml (12 mmol) of 0.6 molar aqueous potassium iodide are added to the red liquid, and the mixture is stirred for 4 h. The black crystals are collected, washed with water, and dried over sulfuric acid yield 1.48 g (100%) m.p. 140° (dec.)... 

Figure 7.8. A. two-dimensional DAS spectrum of glassy Na2Te409 acquired at a magnetic field of 8.46 T at spinning speeds of 5.5-6.0 kHz and rotor angles of 37.38° and 79.19° to the magnetic field. The maximum of the peak projection onto the isotropic shift axis is taken as the most probable isotropic shift. Note that the shifts are referenced to solid NaCl. B. Variation with glass composition of the most probable isotropic chemical shifts at two magnetic fields deduced from the DAS spectra of sodium tellurite glasses (referenced to solid NaCI). From Tagg et al.

Distillation Methods Distillation methods have been widely used in iodine isotope production. Since iodine may be converted to a volatile form (I2), either wet distillation or dry distillation has been employed. A general distillation procedure for carrier-free purification has been reported earlier by Kahn and Freedman (1954). In a wet distillation method (IAEA, 1966), irradiated Te metal is dissolved in a chromic acid-H2S04 mixture. After complete dissolution, the iodate (IO3) formed is reduced to elemental iodine (I2) with oxalic acid and then distilled off from the solution. The distillate is trapped in alkaline sulfite solution. This solution is then purified by an oxidation-reduction cycle and finally redistilled into dilute alkaline solution. In another wet distillation method, irradiated Te02 is dissolved in NaOH and the sodium tellurite is oxidized with H2O2 in the presence of a catalyst, sodium molybdate. The mixture is then acidified with H2SO4 and the iodine is distilled off and trapped in ice-cold water. 

The higher sulfides of tellurium such as TeS2 and TeSs, are obtained from tellurite solutions by precipitation with hydrogen sulfide or sodium sulfide. Tellurium reacts with concentrated sulfuric acid to form red oxysulfide of the composition, TeSOs. With nitric acid, the metal is oxidized to dioxide, Te02. Oxidation of tellurium with chromic acid or potassium permanganate in nitric acid yields orthotelluric acid (HeTeOe). 

Tellurium occurs chiefly as telluride in gold, silver, copper, lead, and nickel ores in Colorado. California, Ontario, Mexico, and Peru, and infrequently as free tellurium and tellurite (tellurium dioxide, Te02) The anode mud from copper and lead refineries, or the flue dust from roasting telluride gold ores is treated by fusion with sodium nitrate and carbonate and the melt extracted with water. The resulting solution is acidified carefully with H2S04, whereupon tellurium dioxide is precipitated, and die dioxide reduced to free tellurium by heating with carbon. 

To ths radioactive telluric acid, smell amounts of inactive Bo-tellurite, iodide, and sodium iodsts are added as carriers. At suitable Intervals, aliquots, of this sample are taken and the Isomer separation -parfamed. tBia soln. la flrs fread of IU1 (8 day), vhich had grown from the Te, by reducing the lodate present with an equivalent amount of Iodide and extracting the Iodine with CHJla. 

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