Addition Polyalkylnorbornenes: A Promising New Class of Si‐Free Membrane Materials for Hydrocarbons Separation

Nanoporous glassy polymers are perspective materials for the fabrication of gas separation membranes, especially for the application of gaseous hydrocarbon separation. However, the drawback of such materials is the pronounced physical aging resulting in the dramatic drop of gas transport properties due to relaxation of high‐free‐volume fraction in time. Herein, a novel and readily available group of such glassy polymers is reported based on 5‐alkylnorbornenes. These polymers are easily synthesized from dicyclopentadiene and α‐olefins by Diels‐Alder reaction and vinyl (addition) polymerization of the formed cycloadducts in the presence of ([(η3‐C3H5)PdCl]2/PCy3/Na+[B(3,5‐(CF3)2C6H3)4]− catalyst. The obtained polymers display low‐fraction free volume, stable gas permeability over time, and possess a unique feature for the glassy polymers—solubility controlled permeation of hydrocarbons and enhanced C4H10/CH4 selectivity. Readily available glassy addition polyalkylnorbornenes are a new group of glassy polymers capable of efficiently separating hydrocarbons. These polymers, being low free‐volume and Si‐free, unexpectedly possess solubility‐controlled permeation of hydrocarbons (i.e., they are characterized by higher permeability of heavier components of a mixture).