S-Tetrachloroethane

Reaction XXXV. (b) Condensation of Phthalic Anhydride with Phenols in the presence of Anhydrous Aluminium Chloride, s-tetrachloroethane being used as a Solvent. (B., 52, 2098 53, 826.)—This is an extension of the previous reaction to phenols employment of tetrachloroethane as solvent has enabled satisfactory yields to be obtained. Condensation takes place in the or Ao-position to the hydroxyl group. Thus phenol and phthalic anhydride yield 2-(o-hydroxybenzoyl)-benzoic acid. 

The flask is filled half full with s-tetrachloroethane, and 300 g. of ammonium chloride is added. CavMon Use hood. As a typical chlorinated solvent, this is a toxic material. The mixture is heated to boiling while stirring so as to distill all water into the trap. When the volume of collected water shows no change in an hour s time, the mixture is cooled to about 60°, the trap and condenser are removed, and the condenser is dried and replaced on the flask. To the flask is added 900 g. of phosphorus(V) chloride and the mixture heated to reflux (128 to 143°) for 6 to 20 hours. It is cooled to about 40 to 60° and filtered on a Buchner funnel to remove solids (excess ammonium chloride), which can be rinsed with additional solvent and discarded. 

The product from Run A was found to be completely soluble in s-tetrachloroethane at room temperature, whereas poly(chloro-p-xylyl-ene) is insoluble in this solvent at all temperatures. These marked changes in solubility characteristics are considered excellent evidence for the formation of random copolymers rather than block copolymers or mixtures of homopolymers. 

Synonyms l,l-Dichloro-2,2-dichloroethane Ace-tosal Acetylene tetrachloride Bonoform Cellon Dichloro-2, 2-dichloroethane Ethane, 1,1,2,2-tet-rachloro- TCE (ambiguous) Tetrachloroethane Tetrachloroethane (VAN) Tetrachlorure d acety-lene (French) Westron s-Tetrachloroethane... 

Table 3 gives reaction times at 78.8° observed in solvents of four types. Boiling points and solubilities are included for general interest and in some cases have t bearing on the conduct of the experiment or isolation of the product. Thus tetra> hydrofurane has such pronounced solvent power for the dienone (960 mg./10 ml at 25°) that the reaction can be run at a temperature 13.4° above the boiling point of THF. Other powerful solvents are methylene bromide (888 mg.), bromoforin (876 mg.), and s-tetrachloroethane (760 mg.). For isolation of the adduct it is often necessary merely to cool the suspension, but where necessary a diluent can be added or solvent distilled isolation of adduct in close to quantitative yield seldom presents a problem. 

Preparation. The reagent was first obtained by Liebig2 by the reaction of phosphorus pentachloride and ammonia. At the present time it is prepared from phosphorus pentachloride and ammonium chloride in. s-tetrachloroethane.3... 

SYNONYMS acetylene tetrachloride, tetrachloroethane, symmetrical-tetrachloroethane, s-tetrachloroethane. 

Sodium Pyrene-3-sulfonate. To a cooled solution of 1 equivalent of pyrene in 6 volumes of s-tetrachloroethane there is added dropwise with stirring the calculated amount of chlorosulfonic acid (2 equivalents) dissolved in an equal voliune of s-tetrachloroethane. The temperature is nuuntained at 0 5 during the addition. The mixture is stirred for fifteen... 

When bromine was added slowly to PPO dissolved in s-tetrachloroethane at 140°C polymer 6 with up to 90% benzylic bromination was obtained. (Scheme 3) Reduction with lithium aluminum hydride regenerates the original polymer with the same molecular weight indicating no cleavage reactions took place during the reaction. 

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