Molecular sieving of iso-butene from C4 olefins with simultaneous high 1,3-butadiene and n-butene uptakes
Junhui Liu, Hanting Xiong, Shuai Hua, Xing Liu, Yong Peng, Lingmin Wang, Pengxiang Wang, Zhiwei Zhao, Zhenning Deng, Zhenyu Zhou, Jingwen Chen, Shixia Chen, Zheling Zeng, Shuguang Deng, Jun Wang
Abstract
Abstract Iso-butene (iso-C 4 H 8 ) is an important raw material in chemical industry, whereas its efficient separation remains challenging due to similar molecular properties of C 4 olefins. The ideal adsorbent should possess simultaneous high uptakes for 1,3-butadiene (C 4 H 6 ) and n-butene (n-C 4 H 8 ) counterparts, endowing high efficiency for iso-C 4 H 8 separation in adsorption columns. Herein, a sulfate-pillared adsorbent, SOFOUR-DPDS-Ni (DPDS = 4,4′-dipyridyldisulfide), is reported for the efficient iso-C 4 H 8 separation from binary and ternary C 4 olefin mixtures. The rigidity in pore sizes and shapes of SOFOUR-DPDS-Ni exerts the molecular sieving of iso-C 4 H 8 , while exhibiting high C 4 H 6 and n-C 4 H 8 uptakes. The benchmark Henry’s selectivity for C 4 H 6 /iso-C 4 H 8 (2321.8) and n-C 4 H 8 /iso-C 4 H 8 (233.5) outperforms most reported adsorbents. Computational simulations reveal the strong interactions for C 4 H 6 and n-C 4 H 8 . Furthermore, dynamic breakthrough experiments demonstrate the direct production of high-purity iso-C 4 H 8 (>99.9%) from C 4 H 6 /iso-C 4 H 8 (50/50, v / v ), n-C 4 H 8 /iso-C 4 H 8 (50/50, v / v ), and C 4 H 6 /n-C 4 H 8 /iso-C 4 H 8 (50/15/35, v / v / v ) gas-mixtures.