# Efficient Separation of C2H6/C2H4 and C3H8/C2H6/CH4 Light Hydrocarbons Using Robust Porous Polymer Networks for C2H4 and CH4 Purification

## TL;DR

This paper introduces new materials that can efficiently separate light hydrocarbons, offering a better alternative to energy-intensive cryogenic distillation.

## Contribution

The study presents four new porous polymer networks with record selectivity for separating C2H4 and CH4 from hydrocarbon mixtures.

## Key findings

- PPN-35 achieved the highest reported C2H6/C2H4 selectivity of 1.67.
- PPN-45 showed the highest C3H8/C2H6 selectivity of 79.73.
- Breakthrough experiments confirmed >99% purity for both C2H4 and CH4.

## Abstract

The efficient production of ultrahigh-purity C2H4 and CH4, 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 C2H4 from C2H6/C2H4 mixtures
and CH4 from C3H8/C2H6/CH4 mixtures. PPN-35, PPN-45, PPN-55, and PPN-65 exhibit IAST selectivities
of 1.67, 1.43, 1.24, and 1.34 for C2H6/C2H4; 345.33, 199.16, 135.21, and 269.93 for C2H6/CH4; 20.17, 79.73, 31.77, and 15.98
for C3H8/C2H6; and 61907.55,
284358.59, 18175.83, and 19484.73 for C3H8/CH4, 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 C2H6/C2H4 selectivity of 1.67 achieved by PPN-35 is the highest reported for any PPN, and the C2H6/CH4, C3H8/C2H6, and C3H8/CH4 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 C2H4 and CH4. This work paves the way for exploring PPNs for light hydrocarbon
separation.