From Organo Tellurium Trihalides

Organo tellurium trihalides are converted by aqueous solutions of sodium hydroxide or sodium carbonate or by boiling water to tellurinic acids. 

4-Ethoxybenzenetellurinic Acid To 40 of a 10% aqueous solution of sodium carbonate are added 1.2 g (3.4 mmol) of 4-ethoxyphenyl tellurium trichloride, the mixture is stirred at 20° for 2 h, then filtered. The solid is dried over phosphorus pentoxide in vacuum. The dry product begins to shrink at 200° and decomposes at 235-240°. 

Aryl tellurium trihalides were hydrolyzed with aqueous sodium hydroxide solution. The tellurinic acids were precipitated by acidification of the reaction mixture with acetic, hydrochloric or sulfuric acid.  

4-Hydroxybenzenetellurinic Acid 15 g of 4-hydroxyphenyltellurium trichloride are dissolved in 500 ml of 2 molar aqueous sodium hydroxide solution and the mixture is acidified with 2 normal sulfuric acid. The initially formed precipitate is redissolved by adding sulfuric acid, the solution is allowed to stand for 48 h, the crystalline material is collected, and recrystallized from glacial acetic acid. 

Similarly prepared were 4-ethoxybenzene- and 4-methoxybenzenetellurinic acids.  

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From Organo Tellurium Trihalides and Onium Halides... 

Table 9 Organo Tellurium Trihalides from Equimolar Amounts of Tellurium T etrahalides and Main Group Organomet all ic Com... 

Table 18 Aryl Organo Tellurium Dichlorides or Dibromides from Aryl Tellurium Trihalides and...

Organo tellurium trifluorides, trichlorides, tribromides, and triiodides are known. Aryl tellurium trihalides are generally more stable than alkyl tellurium trihalides. The sensitivity toward atmospheric agents decreases from the trichlorides to the triiodides. Very few organo tellurium trifluorides have been prepared and little is known about their reactivity. The general reactivity of aryl tellurium trihalides decreases from the chlorides to the iodides. 2-Chloroalkyl tellurium trichlorides, products of the addition of tellurium... 

The halogenolysis of dialkyl ditellurium compounds is a convenient method for the preparation of alkyl tellurium trihalides because dialkyl ditellurium compounds are easily accessible through alkylation of disodium ditelluride (p. 258). Diaryl ditellurium compounds generally obtained via reduction of organo tellurium trichlorides (p. 274), serve as starting materials for the syntheses of aryl tellurium tribromides and triiodides (Vol. IX, p. 1156) that are not obtainable from the hydrocarbons and tellurium telrabromide or tetraiodide. 

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