Correlation of adsorbent cavity structure with adsorption behavior and interaction of long-chainα-olefin/paraffin on microporous adsorbents  

作　　者：Ruihan Yang Fangyu Zhao Shafqat Ullah Xiao Chen Junxiang Ma Yuan Gao Yujun Wang Guangsheng Luo 

机构地区：[1]State Key Lab of Chemical Engineering,Department of Chemical Engineering,Tsinghua University,Beijing 100084,China [2]Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology,Department of Chemical Engineering,Tsinghua University,Beijing 100084,China [3]Lu’an Chemical Group CO.,LTD.,Changzhi 046299,China

出　　处：《Nano Research》2023年第4期5721-5732,共12页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.21878169 and 21991102);the National Key Research and Development Program of China(No.2019YFA0905100);the Tsinghua University Initiative Scientific Research Program(No.2018Z05JZY010).

摘　　要：Long-chainα-olefins have a high added value as important raw materials for many highly marketable products.Fishcher-Tropsch synthesis products contain ultrahigh-contentα-olefins,which are of great value if the challenging separation ofα-olefin/paraffin is achieved through energy-saving ways,for which adsorption separation is an attractive technology.One of the most significant differences between the adsorption separation of long-chain and light hydrocarbons is the steric hindrance of the molecular chain.Herein,we propose a combination of window size,metal node spacing,and bending degree to quantitatively describe the adsorption cavity structure for the separation of long-chainα-olefin/paraffin.The general cavity structural characteristics of microporous materials with good separation performance for long-chainα-olefin/paraffin are revealed.The selective adsorption of liquid C6 and C_(8)α-olefin/paraffin mixtures on CuBTC(BTC=benzene-1,3,5-tricarboxylate)was studied in detail to reveal the influence of the cavity structure on the adsorption and interaction using a combination of batch adsorption experiments and molecular simulation techniques.CuBTC exhibited 360 and 366 mg/g olefin adsorption capacities for C6 and C8 linearα-olefins,respectively.The adsorption energies were−0.540 and−0.338 eV for C8 linearα-olefin and paraffin,respectively.The contributions of different types of interactions to the overall adsorption energy were quantified to illustrate the adsorption energy difference betweenα-olefin/paraffin and CuBTC.This work provides a new understanding of the long-chain hydrocarbon adsorption behavior different from ethylene/ethane and propylene/propane,which guides the design of adsorbents forα-olefin/paraffin separation.

关 键 词：linearα-olefin adsorption cavity structure metal-organic framework liquid-phase adsorption molecular simulations principal orbital interaction 

分 类 号：O64[理学—物理化学]