1,1 -dihydroperfluorooctyl acrylate

Although CO2 dissolves many small molecules readily, it is a very poor solvent for most high molecular weight polymers. Currently, only amorphous or low melting fluoropolymers and silicone polymers are known to be very soluble in CO2 (T < 100 °C, P < 400 bar), or C02-philic, while many industrially important polymers are relatively insoluble. In 1992, we reported the successful homogenous free radical polymerization of a C02-philic fluorinated acrylate, 1,1-dihydroperfluorooctyl acrylate (FOA)2. Homogenous polymer synthesis in CO2 is fundamentally limited however, by the extremely low solubility of most polymers at readily accessible conditions. 

Oxidative coupling polymerization in SCCO2 has been demonstrated for the synthesis of poly(2,6-dimethylphenylene oxide) 27. The polymerization of 2,6-dimethylphenol in the presence of oxygen is conducted using CuBr as the catalyst, pyridine and a block copolymer of styrene and 1,1-dihydroperfluorooctyl acrylate (PS- -PFOA) as a stabilizer in SCCO2 (350 bar) at 40 C. The polymerization occurred via a dispersion process and produced the polymer in a 74% yield with high molecular weight (17 000) (Scheme 46). 

DeSimone and co-workers have examined the kinetics of decomposition of the free radical initiator 2,2 -azobis(isobutyronitrile) (AIBN) in SC-CO2 and have also demonstrated the possible synthetic utility of SC-CO2 via the free radical polymerization of 1,1-dihydroperfluorooctyl acrylate (FOA, equation 5) (27,22). 

Poly (1,1 -dihydroperfluorooctyl acrylate) carbon dioxide 1998LUN... 

Homogeneous Solution Polymerization in Supercritical Carbon Dioxide These polymerizations require that the monomer, the initiator and the polymer remain in solution throughout the reaction. Because carbon dioxide is not a very good solvent for majority of polymers, homogeneous solution polymerizations have been limited to either low conversion operations, or to a few special, mostly fluorinated, monomer/polymer cases that display high solubility in carbon dioxide. A well-known example is the polymerization of 1,1 dihydroperfluorooctyl acrylate (FOA) to from poly(FAO)[3, 17]. 

Hsiao Yu Ling, Maury Elise E., DeSimone Joseph M., Mawson Simon, and Johnston Keith P. Dispersion polymerization of methyl methacrylate stabilized with poly (1,1-dihydroperfluorooctyl acrylate) in supercritical carbon dioxide. Macromolecules. 28 no. 24 (1995) 8159-8166. 

Acrylamide (ultra pure electrophoresis grade form Polysciences, Inc.) was used without further purification. Laurylacrylate (6) (Monomer-Polymer Labs) was purified by washing with 1 M NaOH followed by vacuum distillation. The 1,1-dihydroperfluorobutyl acrylate (2) and 1,1-dihydroperfluorooctyl acrylate (3) were purchased from Monomer-Polymer Laboratories and used as received. The fluorine containing surfactants and monomers, 2-(AT-ethylperfluorooctane-sulfoamido)ethylacrylate (4) and -methacrylate (5) technical grade were donated by the 3M Company. The monomers were recrystallized from MeOH. All of the solvents and salts were of reagent grade or ACS grade quality. The AMPS monomer (sodium salt Aldrich) was used as received. 

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