Tailoring Pore Structure and Acidity of Mg‐NiAPO‐11 Molecular Sieves for Enhanced Catalytic Performance in 2‐Butene Skeletal Isomerization

ABSTRACT In the isomerization of 2‐butene, the distribution of acid sites and the pore structure of molecular sieve catalysts play crucial roles in determining reaction selectivity and stability. This study presented a dual‐template strategy to enhance the conversion of 2‐butene to isobutene over Mg‐NiAPO‐11‐CTAB, with cetyltrimethylammonium bromide (CTAB) and dipropylamine (DPA) serving as mesopore and micropore directing agents, respectively. The incorporation of CTAB modified the pore structure and introduced mesoporous contributions, which may facilitate the diffusion of reactants and products. Meanwhile, CTAB altered the apparent acid‐site distribution, with an increased contribution from weak acid sites that may favor isobutene formation. At a CTAB/Al molar ratio of 0.15, the optimized Mg‐NiAPO‐11‐CTAB(0.15) catalyst achieved a 2‑butene conversion of 61.22% and an isobutene yield of 52.04%. Furthermore, the catalyst exhibited excellent long‐term stability, maintaining an isobutene yield of around 52% during a 72 h time‐on‐stream test. Based on response surface methodology, the optimal operating conditions were determined to be 371°C, a weight hourly space velocity of 4.8 h −1 , and a 2‑butene feed volume ratio of 19.5%, yielding 54.07% isobutene. This work outlines an effective pore and acidity engineering approach for zeolite catalysts in selective C4 conversion.