The fixation of carbon dioxide with epoxides catalyzed by cation-exchanged metal-organic framework

• Published in: Microporous and mesoporous materials Vol. 258; pp. 55 - 61
• Main Authors: Zhang, Xinlu, Chen, Zijuan, Yang, Xiaoqian, Li, Meiyan, Chen, Chao, Zhang, Ning
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.03.2018
• Subjects: Alkali metal; Cation-exchanged; CO2; Cyclic carbonate; Metal-organic frameworks; Cyclic carbonate; Alkali metal; Metal-organic frameworks; CO2; Cation-exchanged
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2017.08.013

Metal-organic frameworks (MOFs) possess high porosity and specific surface area and have been extensively applied in the capture and separation of CO2 from flue gas or natural gas. UTSA-16 is the second highest porous MOF for CO2 capture, which is attributed to its microporous structure with anatase type and the fact that the K+ species located in the channel can interact with CO2 molecule. Herein, a sequence of alkali metal cation-exchanged UTSA-16 (hereinafter denoted as M-UTSA-16, M = Li, Na, K, Rb, Cs) were prepared and evaluated for CO2 capture. The CO2 adsorption isotherms of M-UTSA-16 obtained at 273K and 298K showed that the adsorption capacity for CO2 decreased in the sequence of K+>Na+>Li+>Rb+>Cs+. The series of M-UTSA-16 were used as the catalyst for the transformation of CO2 and epoxide to cyclic carbonate in the absence of co-catalyst. Li-UTSA-16 exhibited the highest efficiency of catalytic activity compared with other M-UTSA-16. The result was inconsistent with the sequence of CO2 adsorption capacity. The further systematic investigation showed that the decreasing order of catalytic activities of M-UTSA-16 was in agreement with the sequence of increasing radius of the exchanged cations as well as the heat of adsorption for CO2 at lower pressure region. A series of M-UTSA-16(M=Li,Na,K,Rb,Cs) possessing analogous structures with various alkali metals by cation-exchanged method exhibited efficiently catalytic performance cycloaddition reaction from CO2 and epoxides in the absence of co-catalyst. [Display omitted] •A sequence of UTSA-16 (denoted as M-UTSA-16, M = Li, Na, K, Rb, Cs) were prepared by cation-exchange.•Li-UTSA-16 exhibited the highest catalytic activity for the transformation of CO2 and epoxide to cyclic carbonate.•The catalytic activities of M-UTSA-16 decreased in the sequence of Li+> Na+>K+>Rb+>Cs+.•The decreasing order of catalytic activities is in agreement with the sequence of increasing radius of the cations.•Li-UTSA-16 can be reused at least five times with no significant loss in activity and selectivity.