Microporous polymers from superacid catalyzed polymerizations of fluoroketones with p-quaterphenyl: Synthesis, characterization, and gas sorption properties

Novel fluorinated aromatic polymers were obtained by one-pot, metal-free, superacid-catalyzed step-polymerization of trifluoromethylalkyl 1(a-b) and trifluoromethylaryl (1c) ketones with p-quaterphenyl (A). The room temperature polymerizations performed in a mixture of trifluoromethanesulfonic acid (CF3SO3H, TFSA) with methylene chloride gave polymeric particles. Thermogravimetric analysis for the particles revealed insignificant weight loss below 500 °C confirming their polymeric nature. Studies of solid state NMR revealed the incorporation of p-quaterphenyl in the polymer chain. The regioselectivity of polymerizations involving p-quaterphenyl and fluoroketones has been confirmed by the preparation and NMR characterization of soluble copolymers of trifluoroacetophenone (1c) with p-terphenyl/quaterphenyl mixtures. Conformational rigidity and free volume calculations confirm polymers with medium hardness and with free volumes around 0.205–0.221 cm3/g. Scanning electron microscopy show rough surfaces with pore sizes around 20–50 nm. The H2, N2 and CO2 adsorption isotherms show that these polymers may possess intrinsic microporosity making them potential molecular sieves.