Thermodynamic‐Kinetic Synergistic Separation of Light Olefins/Paraffins in Post‐Synthetically Modified Small‐Pore Zeolites

Abstract The search for selective microporous adsorbents in light olefin/paraffin separations presents many challenges in replacing current energy‐intensive cryogenic distillation processes. Here, it is demonstrated that modified acidic intermediate‐silica small‐pore zeolites, for example, the proton form of zeolite rho with a Si/Al ratio of 3.3 (H‐rho), using ammonium fluoride/hydrogen peroxide etching followed by phosphorus loading, can decisively improve ethylene/ethane and propylene/propane separation performances based on the thermodynamic‐kinetic synergistic mechanism. 2.0 (I) and 1.2 (II) weight% phosphorus loadings on etched H‐rho afford steady‐state ethylene and propylene productivities (≥99.5%) of 28.8 and 33.7 L kg ⁻¹ under dynamic breakthrough conditions using equimolar ethylene/ethane and propylene/propane mixtures, respectively. Also, a combination of these two loadings in a dual‐layer configuration of I on top and II on bottom provides a steady‐state propylene productivity (≥99.5%) of 23.5 L kg ⁻¹ and a recovery yield of 81% under the same conditions using an equimolar four‐component (ethylene/ethane/propylene/propane) mixture. This study opens a new avenue for the design and development of zeolite molecular sieves for multicomponent light olefin/paraffin separations.