Efficient Separation of C ₂ H ₆ /C ₂ H ₄ and C ₃ H ₈ /C ₂ H ₆ /CH ₄ Light Hydrocarbons Using Robust Porous Polymer Networks for C ₂ H ₄ and CH ₄ Purification

High Resolution Image Download MS PowerPoint Slide The efficient production of ultrahigh-purity C 2 H 4 and CH 4, which are vital feedstocks for industrial processes and alternative energy, is increasingly in demand but remains challenging. Cryogenic distillation has been widely utilized for this purpose; however, it imposes a substantial energy burden. Herein, we report four robust porous polymer networks (PPNs), namely, PPN-35, PPN-45, PPN-55, and PPN-65, for the purification of C 2 H 4 from C 2 H 6 /C 2 H 4 mixtures and CH 4 from C 3 H 8 /C 2 H 6 /CH 4 mixtures. PPN-35, PPN-45, PPN-55, and PPN-65 exhibit IAST selectivities of 1.67, 1.43, 1.24, and 1.34 for C 2 H 6 /C 2 H 4; 345.33, 199.16, 135.21, and 269.93 for C 2 H 6 /CH 4; 20.17, 79.73, 31.77, and 15.98 for C 3 H 8 /C 2 H 6; and 61907.55, 284358.59, 18175.83, and 19484.73 for C 3 H 8 /CH 4, respectively. These values demonstrate that the materials are promising candidates to replace the widely used cryogenic distillation process. To the best of our knowledge, the C 2 H 6 /C 2 H 4 selectivity of 1.67 achieved by PPN-35 is the highest reported for any PPN, and the C 2 H 6 /CH 4, C 3 H 8 /C 2 H 6, and C 3 H 8 /CH 4 selectivities surpassed all those of sorbents reported in the literature. Each of the four PPNs exhibits high adsorption capacities, and their practical usability was validated through breakthrough experiments, yielding >99% purity for both C 2 H 4 and CH 4 . This work paves the way for exploring PPNs for light hydrocarbon separation.