“…Hence, the yield in this step was moderate. Similarly, the dioxolane derivatives have been prepareed from pyruvic acid in a yield about 50% 1 Synthesis of Perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolane 2 Synthesis of Perfluoro-3-methylene-2,4-dioxabicyclo[4.3.0]nonane …”
A new efficient synthetic route was developed for perfluorinated 2-methylene-1,3-dioxolane monomers via a direct fluorination of the hydrocarbon precursors prepared from methyl pyruvate and diols. Perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolane (PMDD) and perfluoro-3-methylene-2,4-dioxabicyclo-[4.3.0]nonane (PMDN) were thus synthesized via this new method, among which PMDN is first reported. The radical polymerizations of those monomers were performed under various conditions. The kinetic results indicated that polymerization rate of PMDD is higher than that of PMDN. Oxygen did not affect the polymerization yield but strongly affected the polymer structure. The polymerization in the presence of oxygen produced a polymer containing unstable units. Hydrogen-containing solvents result in a lower molecular weight polymer. 2,2′-Azobis(isobutyronitrile) cannot initiate the polymerization in a perfluoro solvent or in bulk. Also, photopolymerizations of those monomers were performed in the presence of carbon tetrabromide or carbon tetrachloride, and the mechanism is discussed. The polymer of PMDD has a glass transition temperature at 155°C, and the polymer of PMDN has a glass transition temperature at 161°C. These polymers with high glass transition temperature, low refractive index, low material dispersion, and extraordinary optical transmission from the deep ultraviolet to near-infrared regions may be used as optical fibers, pellicles, or antireflective coating materials.
“…Hence, the yield in this step was moderate. Similarly, the dioxolane derivatives have been prepareed from pyruvic acid in a yield about 50% 1 Synthesis of Perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolane 2 Synthesis of Perfluoro-3-methylene-2,4-dioxabicyclo[4.3.0]nonane …”
A new efficient synthetic route was developed for perfluorinated 2-methylene-1,3-dioxolane monomers via a direct fluorination of the hydrocarbon precursors prepared from methyl pyruvate and diols. Perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolane (PMDD) and perfluoro-3-methylene-2,4-dioxabicyclo-[4.3.0]nonane (PMDN) were thus synthesized via this new method, among which PMDN is first reported. The radical polymerizations of those monomers were performed under various conditions. The kinetic results indicated that polymerization rate of PMDD is higher than that of PMDN. Oxygen did not affect the polymerization yield but strongly affected the polymer structure. The polymerization in the presence of oxygen produced a polymer containing unstable units. Hydrogen-containing solvents result in a lower molecular weight polymer. 2,2′-Azobis(isobutyronitrile) cannot initiate the polymerization in a perfluoro solvent or in bulk. Also, photopolymerizations of those monomers were performed in the presence of carbon tetrabromide or carbon tetrachloride, and the mechanism is discussed. The polymer of PMDD has a glass transition temperature at 155°C, and the polymer of PMDN has a glass transition temperature at 161°C. These polymers with high glass transition temperature, low refractive index, low material dispersion, and extraordinary optical transmission from the deep ultraviolet to near-infrared regions may be used as optical fibers, pellicles, or antireflective coating materials.
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