METHOD OF SEPARATING CO/N AND CO/CH GAS MIXTURES USING MEMBRANE OF ADDITIVE POLY(N-(3,5-BIS(TRIFLUOROMETHYL)PHENYLNORBORNENE-5,6-DICARBOXYIMIDE) Russian patent published in 2025 - IPC C08F12/20 B01D71/44 C07C7/144 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of separating a CO₂-containing gas mixture selected from CO₂/N₂ and CO₂/CH₄ using a membrane made from additive poly (N-(3,5-bis (trifluoromethyl) phenylnorbornene-5,6-dicarboxyimide). Method of separating CO₂-containing gas mixture selected from CO₂/N₂ and CO₂/CH₄ includes supplying a gas mixture from one side of a selectively permeable membrane made from additive polynorbornene, which includes imide fragments and collecting components penetrating through it from the other side, wherein the additive polynorbornene used is an additive poly(N-3,5-bis(trifluoromethyl)phenylnorbornene-5,6-dicarboxyimide) of structural formula:

characterized by degree of polymerisation 1900, weight average molecular weight M_w=646⋅10³ g/mol and polydispersity index M_w/M_n = 1.2, obtained by polymerisation of monomer - (N-3,5-bis(trifluoromethyl)phenylnorbornene-5,6-dicarboxyimide) in presence of Pd-containing catalyst system consisting of Pd -N-heterocyclic carbene complex - SIMesPd(cinn)Cl and silver hexafluorostibate AgSbF₆, obtained by mixing components of the catalyst system in an organic solvent - methylene chloride in the reaction zone immediately before polymerisation of the monomer at a molar ratio of components in the reaction mass [monomer]:[Pd]:[AgSbF₆] = 1000:1:3; with intensive mixing of reaction mass and polymerisation at 45 °C for 8 hours, precipitation of obtained polymer in methanol, drying in vacuum for 3 hours to constant weight, followed by re-precipitation of the tetrahydrofuran polymer with methanol and drying in a vacuum, the procedure is repeated twice to obtain said additive polynorbornene.

EFFECT: obtaining poly(n-(3,5-bis(trifluoromethyl)phenylnorbornene-5,6-dicarboxyimide)polymer with degree of polymerisation of 1900, with weight average molecular weight M_w=646⋅10³ g/mol and polydispersity index M_w/M_n=1.2, which provides better film-forming properties of the obtained polymer and, as a result, higher permeability and selectivity; wherein an interesting property of this polymer is an increase in selectivity with an increase in permeability; in increasing permeability by CO₂ up to 1370 barrers and selectivity CO₂/N₂ = 32 and CO₂/CH₄ = 29; increase of polymer output to 78%; in increasing efficiency and simplifying the hardware implementation of the proposed method, due to the [monomer]/[Pd] ratio in the disclosed method, which is associated with a decrease in the catalyst consumption and by performing additive polymerisation in air in the absence of argon; providing higher chemical stability, due to the fact that the obtained polymer contains only saturated main chains, which makes it possible to ensure higher chemical stability.

1 cl, 3 dwg, 2 tbl, 3 ex