Polymerization bromophenols

Halophenols without 2,6-disubstitution do not polymerize under oxidative displacement conditions. Oxidative side reactions at the ortho position may consume the initiator or intermpt the propagation step of the chain process. To prepare poly(phenylene oxide)s from unsubstituted 4-halophenols, it is necessary to employ the more drastic conditions of the Ullmaim ether synthesis. A cuprous chloride—pyridine complex in 1,4-dimethoxybenzene at 200°C converts the sodium salt of 4-bromophenol to poly(phenylene oxide) (1) ... 

However, the recent work on polymerization of salts of 2.6-dichloro-4-bromophenol under anhydrous conditions in the presence of aprotic dipolar solvents apparently gives a linear high molecular weight polymer as judged by the analytical data (see Experimental) and properties of the polymer as summarized in the following tables (26). 

Poly(oxy-1,4-phenylene) is obtained by electrooxidative polymerization of / -bromo-phenol in aqueous NaOH solution. The yield increases when aqueous NaOH is replaced by aqueous KOH or when the reaction is conducted at higher temperature. In contrast, p-chlorophenol electrooxidatively dimerizes to give the biologically and pharmacologically important dioxin, 2,7-dichlorodibenzo[, ][l,4]dioxine254. In an effort to find protective chemical coatings, electrooxidative polymerization of ra-chlorophenol and ra-bromophenol was observed255. 

This sequence explains Price s observations adequately and seems to be required in this particular case. The oxidative elimination of halide ion from salts of phenols does not always follow this course, however. In the peroxide-initiated condensation of the sodium salt of 2,6-dichloro-4-bromophenol (Reaction 23) molecular weight continues to increase with reaction time after the maximum polymer yield is obtained (Figure 5) (8). Furthermore, Hamilton and Blanchard (15) have shown that the dimer of 2,6-dimethyl-4-bromophenol (VIII, n = 2) is polymerized rapidly by the same initiators which are effective with the monomer. Obviously, polymer growth does not occur solely by addition of monomer units in either Reaction 22 or 23 some process leading to polymer—polymer coupling must also be possible. Hamilton and Blanchard explained the formation of polymer from dimer by redistribution between polymeric radicals to form monomer radicals, which then coupled with polymer, as in Reaction 11. Redistribution has indeed been shown to occur under... 

After the stacking gel has polymerized for at least 30 min, the sample comb is removed and the upper and lower reservoir chambers are filled with Electrode Buffer (25 mM Tris-HCl, 192 mM glycine, 0.1% SDS, pH 8.3). The samples are prepared by mixing four parts of sample with one part of 5X Sample Buffer (175 mM Tris-HCl, pH 6.8, 11% SDS, 0.14% bromophenol blue, 55% glycerol, +2 M DTT). The samples are heated at 95°-100° C for 2-5 min. Each sample well is rinsed with Electrode Buffer before applying the samples to individual wells. The gel s electrodes are then connected to the power supply and the gels are run at a constant current of 40 mA per gel until the tracking dye reaches the bottom of the gel ( 4 hr). 

Once the solution is heated to dissolve the agarose, the solution is cooled momentarily and poured into a slab mold fitted at one end with a Teflon or plastic comb. After the solution polymerizes, the comb is removed to create wells into which the desired DNA or RNA samples will be applied. The gel is then transferred to an electrophoresis chamber and is completely covered with the same TAE or TBE buffer that was used to cast the gel. Next, the nucleic acid sample is mixed with a viscous buffer (30% glycerol) containing one or more tracking dyes that will be used to monitor the progress of the electrophoresis. Bromophenol blue dye will migrate at the same rate as a DNA molecule of about 500 base pairs, while xylene cyanole... 

Trade names of two polymeric flame retardants have been reported in the technical literature Fire Guard 7500 (159, Sankyo Organic Chemicals, Co), a functionalized oligocarbonate for ABS prepared from 4,4 -isopropylidenebis(di-bromophenol) and FR 1025, poly(pentabromobenzyl acrylate) (76, Technion) [68]. 

Many reports have focused on the functionalization and derivatization of cyclo-pentadienyl groups bound to iron in ferrocene complexes. As an example, a series of ferrocenyl esters have been prepared via solvent-free reactions of ferrocenoyl fluoride with substituted phenols after microwave heating for just 1 min. " In the case of 4-bromophenol, the YIF was 1.2, but most substrates gave somewhat lower yields than the conventional method. However, the microwave approach did not require the addition of A, A -dimethylaminopyridine that was necessary conventionally. Other reports include a green approach to the acylation of ferrocene using the polymeric sulfonic acid Nation as an acid catalyst " and a one-pot approach to the synthesis of l,5-dioxo-3-substituted[5]ferrocenophanes from l,T-diacetylferrocene and aldehydes via a Claisen-Schmidt reaction. " " ... 

T. Yokozawa and H. Shimura. Condensative chain polymerization. II. Preferential esterification of propagating end group in Pd-catalyzed CO-insertion polycondensation of 4-bromophenols derivatives. J. Polym. ScL, Part A Polym. Chem. 37(14), 2607-2618 (1999). 

A similcu procedure was used for the other polymerizations of VII and either I or IV. In some cases, the bromophenol concentration differed subst intially and the dibutylamine concentration was changed proportionately. 

Highly brominated poly(2,6-dimethyl-l,4-phenylene oxide)s have been prepared by polymerization of bromophenols and by... 

The preparation of bromine-containing polyphenylene oxides by modification of Price s polymerization of bromophenols was described in the preceding paper. An alternate route to these polymers is the direct bromination of polyphenylene oxides. The bromination of poly(2,6-dimethyl-l,4-phenylene oxide) to... 

Furthermore, m-cresol and m-halogenated phenols have been polymerized in aqueous buffer solution only in the presence of 2,6-di-0-methyl-[)-cyclodextrin [90]. In the absence of cyclodextrin, only insoluble materials in very low yields were obtained under aqueous conditions from these phenols [81]. The structure of the host-guest complexes between cyclodextrin and the phenols was characterized by 2D NMR [48,90] and the association constants of the cyclodextrin complexes were determined by the Benesi-Hildebrand method. Firrthermore, 3-fluorophenol, 3-chlorophenol, and 3-bromophenol were successfully polymerized in various aqueous organic solvents such as methanol, acetone, or isopropanol [115]. 

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