Polymerization by oxidative coupling. IV. Polymerization of 4‐bromo‐ and 4‐chloro‐2,6‐dimethylphenol and preparation and decomposition of the silver and copper salts of certain other phenols

Abstract

In the present paper it has been shown that the 4‐halo‐2,6‐dimethylphenols can be polymerized to high molecular weight poly‐2,6‐dimethylphenylene ethers by the action of cupric ions, providing pyridine is also present. This reaction requires a stoichiometric amount of cupric ions and probably proceeds through complexed phenoxy radicals. Although the polymerization cannot be initiated by catalytic quantities of cupric ions, the same cupric salts which are active in the stoichiometric reaction will initiate the polymerization of the 4‐halo‐2,6‐dimethylphenols in basic solution. Here too, the products are high molecular weight polyarylethers and this reaction probably involves the displacement of halide ions by phenoxy radicals. The presumed di‐2,4,6‐trihalophenolate–bispyridine–copper(II) complexes were prepared and characterized. These complexes were decomposed under a variety of conditions, yielding polyhalophenylene ethers, which are highly branched as evidenced by their low intrinsic viscosities. Moreover, they are also terminated, probably through dioxin formation, since they show little or no residual hydroxyl in the infrared. Similarly, the polyhalophenylene ethers prepared by decomposition of the silver salts are also branched and terminated. In this connection, however, silver 4‐chloro‐ and silver 4‐bromo‐2,6‐dimethylphenolates were prepared and decomposed to a poly‐2,6‐dimethylphenylene ether of molecular weight 1800–2200 possessing one halogen and one hydroxyl per polymer chain. The infrared spectrum of this polymer, with the exception of the hydroxyl region, agrees in detail with the infrared spectrum of high molecular weight poly‐2,6‐dimethylphenylene ether prepared by oxidation of 2,6‐dimethylphenol and thus provides a proof for the gross structure of the polymer. Finally, it was found that the blue to blue‐green solutions produced from the decomposition of certain of the copper complexes and the silver salts, respectively, are diamagnetic. This finding mitigates against the participation of phenoxy radicals as the active species in these polymerizations.

Poly(dibromophenylene oxide)s Through Atom Transfer Radical Rearrangement Polymerization of Various Transition Metal Complexes

“…Table 1. MS data for Ni(TBP) 2 (NMIZ) 2 and Cu(TBP) 2 (NMIZ) 2 (The acceptable error limit in data evaluation is ± 2 units).…”

“…A sharp exothermic peak at 116.88 • C and two endothermic peaks at 171.95 • C and 205.83 • C were observed in DSC thermograms of Cu(TBP) 2 (NMIZ) 2 ( Figure 2(a)). Co(TBP) 2 (NMIZ) 2 complexes (Figure 2(b)) showed a sharp exothermic peak at 132.5 • C and an endothermic peak at 184.53 • C ,whereas Ni(TBP) 2 (NMIZ) 2 (Figure 2(c)) showed a single sharp exothermic peak at 143.93 • C. The exothermic peaks are attributed to the new bond formation during polymerization. This vision was previously supported by DSC-IR study (16) which showed the polymer formation at the peak temperature and the increase in the % conversions during polymerization beyond the exothermic peak temperatures.…”

“…Solid state thermal polymerization of Cu(TBP) 2 (NMIZ) 2 , Co(TBP) 2 (NMIZ) 2 and Ni(TBP) 2 (NMIZ) 2 complexes were performed under two different conditions. In the first condition, time kept constant at 3 h and temperature varied between 100 • C to 250 • C. Under the second condition, the temperature was kept constant at maximum conversion temperature and the time varied from 3 to 48 h. The calculated yields for the polymerizations were based on the initial weight of the complexes; since the ligand and metal do not incorporate into the polymer, the results may appear to be low in value.…”

“…The original synthesis was achieved by Hunter and his colleagues through the ethyl iodide-induced decomposition of anhydrous silver 2,4,6 trihalophenoxide (1). In 1962 Blanchard et al (2) showed the possibility to polymerize 4-halo-2,6-dimethylphenols into high molecular weight poly(2,6-dimethylphenylene ether)s by the action of cupric ions, providing pyridine is also present. It was observed that this reaction requires a stoichiometric amount of cupric ions and proceeds through the pyridine complexes of cupric phenolates.…”

Hypochlorous acid-activated carbon: an oxidizing agent capable of producing hydroxylated polychlorinated biphenyls.

“…Reactive free radicals on the carbon surface, produced by its oxidation with chlorine, presumably interact with 2,4-dichlorophenol to generate 2,4-dichlorophenoxy radicals by hydrogen abstraction (14). Trichlorodihydroxybiphenyls may be forned by C-C coupling of a 2,4-dichlorophenol molecule and a 2,4-dichlorophenoxy radical, with displacement of a chlorine atom (15). Tetrachloro analogs would be produced if the C-C coupling occurred at unsubstituted ring positions.…”