Disulfide-containing polymers polymerization

These tellurium-containing polymers were checked for their catalytic activity in the ep-oxidation of olefins1 and as oxidizing agents2. The polymeric 4-methoxyphenyl tellurium oxide did not react with amines, amides, alcohols, or phenols, but oxidized hydroquin-ones to quinones, thiols to disulfides, thioketones to ketones, thioesters to esters, and thiobenzamides in organic solvents to cyanobenzenes and in acetic acid to 2,5-diaryl-4,l,3-thiadiazoles2. 

Tobolsky, A. V. and W. J. MacKnight, Polymeric Sulfur and Related Polymers , Interscience, New York, 1965. A survey of the polymers containing polysulfide linkages rather than monosulfide and disulfide linkages Polym. Rev., vol. 13). 

Sulfur is an interesting atom because of the specific characteristics of the simple substance and compounds containing sulfur. Further, their functions are indispensable for current technologies. Studies on sulfur compounds are valuable not only in chemistry but also in biochemistry as well. Many cyclic monomers containing sulfur such as cyclic disulfides, thiiranes, thietanes, and arene dithiols were reported to form cyclic polymers by the ring-opening polymerization. The natural source of cyclic polymers is believed to be liquid, elemental sulfur [177-179]. 

From the analyses of NMR and electron-spray ionization mass (ESI-MS) spectroscopy, the polymers obtained from the polymerization of cyclic disulfides were found to be a cyclic structure [202], The cyclic structure consisting of poly(DT) is assumed to be formed by a backbiting reaction of propagating species [203]. Thermal and mechanical properties of the polymers, and decomposition behaviors of the polymers demonstrate that the polymers obtained from thermal polymerization of cyclic disulfides include a polycatenane structure. From polymerization of cyclic disulfides in the presence of cyclic polyethylene oxide), a polycatenane consisting of two different cyclic polymers was obtained [199]. Thus, poly(DT) contains spatial entanglements of cyclic polymers with each other (a polycatenane structure was presumed) (Fig. 61). 

After equilibration liquid sulfur contains a certain concentration of polymeric molecules (Soo) at all temperatures. This polymer can be isolated and determined by quenching the melt at very low temperatures, extracting the smaller molecules immediately by pure carbon disulfide at 20 °C, and drying the residue of S in a vacuum. Extraction and drying should be done with exclusion of light and nucleophiles and avoiding higher temperatures which would initiate the conversion of the polymer to cyclo-Ss. The content of jx-sulfur thus obtained depends on the purity of the melt. In addition, it has to be obeyed that the r-sulfur present in the quenched melt is unstable at 20 °C and partly polymerizes to S for which reason the extraction has to be done without any delay if the true polymer content of the melt is to be determined. If, on the other hand, simply S is to be prepared it is possible to in-... 

Similarly bis (3,5-dimethyl phenyl) disulfides yielded the corresponding polymer 209b in the absence of acid. In both cases it is suggested that ArSS+(Ar)SAr, formed in the reaction, effects electrophilic aromatic substitution by acting as an ArS+ donor. This same polymerization process can also be achieved by photooxidation of bis (3,5-dimethylphenyl) disulfide in the presence of 2,3-dicyanonaphthalene as sensitizer in acetonitrile containing trifluoro-acetic acid [486]. 

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