Fluorine-rich poly(arylene amine) membranes for the separation of liquid aliphatic compounds

We explored the potential for membrane materials to reduce energy and carbon requirements for the separation of aliphatic hydrocarbon feedstocks and products. We developed a series of fluorine-rich poly(arylene amine) polymer membranes that feature rigid polymer backbones with segregated perfluoroalkyl side chains. This combination imbues the polymers with resistance to dilation induced by hydrocarbon immersion without the loss of solution-based membrane fabrication techniques. These materials exhibit good separation of liquid-phase alkane isomers at ambient temperatures. The integration of these polymeric membranes into fuel and chemical feedstock separation processes was investigated in a series of experiments. Technoeconomic analyses based on these experiments indicate that the best-performing membrane materials can substantially reduce the energy costs and associated carbon emissions of hydrocarbon separations (two to 10 times, depending on product specifications). Membranes with high selectivity for complex hydrocarbon mixtures and high permeability can potentially reduce the energy footprint of the chemical industry. Ren et al. describe the development of a family of aryl amine polymers with pendent fluorocarbon side chains for organic solvent reverse osmosis. The authors synthesized fluorine containing poly(arylene amine) polymers to fabricate supported thin-film composite membranes with a thickness of 0.2 to 0.3 micrometers. The advantage of these membranes is the suppression of swelling, which typically occurs when polymer membranes are exposed to organic solvents. Membranes were tested for a range of hydrocarbon mixtures that mimic the feed in a Fischer-Tropsch process.

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