Aromatic Polyethers by Oxidative Coupling

Amines such as diethylamine, morpholine, pyridine, andIV,IV,IV, IV -tetramethylethylene-diamine are used to solubilize the metal salt and increase the pH of the reaction system so as to lower the oxidation potential of the phenol reactant. The polymerization does not proceed if one uses an amine that forms an insoluble metal complex. Some copper-amine catalysts are inactivated by hydrolysis via the water formed as a by-product of polymerization. The presence of a desiccant such as anhydrous magnesium sulfate or 4-A molecular sieve in the reaction mixture prevents this inactivation. Polymerization is terminated by sweeping the reaction system with nitrogen and the catalyst is inactivated and removed by using an aqueous chelating agent. 

The polymer from 2,6-dimethylphenol is the commercial product referred to as poly(p-phenylene oxide) or PPO. The lUPAC name is poly(oxy-2,6-dimethyl-l,4-phenylene). PPO 

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