TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The 3C+ hydrocarbon vapor comprises paraffin, olefin, aromatic compound, or halogenated compound, amine, ketone and alcohol. The 2C+ hydrocarbon vapor comprises ethylene. The desired gas is organic compound such as methane and propylene.Preferred Process: The process comprises:(i) separation of hydrogen from gas mixture of hydrogen and 3C+ hydrocarbon vapor;(ii) separation of propane gas from gas mixture of propylene and propane by withdrawing permeate stream enriched in propylene from permeate side and residue stream depleted in propylene form feed side;(iii) separation of nitrogen from gas mixture of nitrogen and 2C+ hydrocarbon vapor by withdrawing permeate stream enriched in nitrogen from permeate side, and residue stream depleted in nitrogen from feed side;(iv) separation of carbon dioxide from gas mixture of carbon dioxide, methane and 3C+ hydrocarbon vapor by withdrawing permeate stream enriched in carbon dioxide from permeate side, and residue stream depleted in carbon dioxide from feed side;(v) separation of methane from gas mixture of methane and 3C+ hydrocarbon vapor by withdrawing permeate stream enriched in methane from permeate side, and residue stream depleted in methane from feed side;(vi) separation of argon from gas mixture of argon and ethylene by withdrawing permeate stream enriched in argon from permeate side, and residue stream depleted in argon from feed side.    TECHNOLOGY FOCUS - POLYMERS - Preferred Polymer: The polymer comprises perfluorinated polymer, fluorinated dioxole monomer, fluorinated dioxolane monomer, fluorinated cyclically polymerizable alkyl ether and/or perfluorinated polyimide. The polymer comprises repeat unit of 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole. The polymer is a polyperfluoro (alkenyl vinyl ether), or a copolymer having repeat units which are copolymerized with repeat units of second fluorinated monomer or tetrafluoroethylene. The polymer has formula (I) or (II).x, y = relative proportions of dioxole and tetrafluoroethylene blocks, such that x+y = 1;n = a positive integer.Preferred Membrane: The separation membrane comprises a composite membrane having gutter layer between support membrane and selective layer. The gutter layer comprises polymer having fluorinated dioxole monomer, or a copolymer of perfluoro-2,2-dimethyl-1,3-dioxole and tetrafluoroethylene. The separation membrane provides pressure-normalized hydrogen flux of at least 200 GPU as measured with pure gas at 25 degreesC. The separation membrane exhibits a mixed-gas selectivity for hydrogen over methane, of at least 10. The separation membrane exhibits mixed-gas selectivity for hydrogen over propane, of at least 50. The residue stream is passed to fuel gas supply. The permeate stream is passed to pressure swing adsorption unit to produce high purity hydrogen stream. The separation membrane exhibits mixed-gas selectivity of propylene over methane, of at least 2.5. The separation membrane exhibits mixed-gas selectivity of nitrogen over methane of at least 2, and nitrogen over ethylene at least 4. The separation membrane exhibits mixed-gas selectivity of carbon dioxide over methane of at least 5, and methane over propane of at least 5. SPECIFIC MATERIALS - The desired gas is hydrogen, nitrogen, oxygen, argon, and carbon dioxide.    EXAMPLE - Asymmetric, microporous poly(vinylidene fluoride), as support membrane was dip-coated in solution of 1 weight% (wt.%) of polyperfluoro(alkenyl vinyl ether) Cytop (RTM) in perfluorinated solvent Fluorinert FC-84 (RTM). The dip-coated membrane was dried at 60 degreesC for 10 minutes. The membrane had selective layer thickness of 0.2-0.5 mum. The finished composite membrane was cut into 12.6 cm2 stamp. The cut sample had nitrogen, hydrogen, argon, carbon dioxide and methane gas fluxes of 34, 620, 56, 300 and 11 GPU respectively. The sample had nitrogen-methane, argon-methane, carbon dioxide-methane, and hydrogen-methane selectivity of 3.2, 5.3, 28 and 59, respectively. Feed gas mixture of 9% argon, 67% methane and 24% ethylene was passed to feed side of sample at 23 degreesC under 165 psia. The pressure-normalized flux of argon-ethylene selectivity was 8.8.