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Strategies for Enhancing the Catalytic Performance of Metal–Organic Frameworks in the Fixation of CO 2 into Cyclic Carbonates
Author(s) -
Taherimehr Masoumeh,
Van de Voorde Ben,
Wee Lik H.,
Martens Johan A.,
De Vos Dirk E.,
Pescarmona Paolo P.
Publication year - 2017
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201601768
Subject(s) - catalysis , metal organic framework , styrene oxide , chemistry , lewis acids and bases , styrene , selectivity , nucleophile , phosphotungstic acid , ionic liquid , heterogeneous catalysis , inorganic chemistry , chemical engineering , organic chemistry , polymer , adsorption , copolymer , engineering
Metal–organic frameworks (MOFs) with accessible Lewis acid sites are finding increasing application in the field of heterogeneous catalysis. However, the structural instability of MOFs when they are exposed to high temperature and/or high pressure often limits their applicability. In this study, two strategies were applied to achieve a MOF catalyst with high stability, activity and selectivity in the reaction of CO 2 with styrene oxide to produce styrene carbonate. In the first approach, a MOF with linkers with high connectivity as MIL‐100(Cr) was studied, leading to promising activity and recyclability in consecutive catalytic runs without loss of activity. In the second strategy, a MOF with linkers with lower connectivity but with encapsulated Keggin phosphotungstic acid (MIL‐101(Cr)[PTA]) was prepared. However, the activity of this catalyst decreased upon reuse as a consequence of deterioration of the MOF. Further investigations were dedicated to the enhancement of the catalytic performance of MIL‐100 and included the variation of the metal centre as well as the type and loading of organic salt acting as nucleophile source. This allowed tuning the nature of the organic halide to the specific porous structure of MIL‐100(Cr) to prevent diffusion limitations. The best catalytic performance was obtained for MIL‐100(Cr) in combination with EMIMBr ionic liquid, which gave very high styrene carbonate yield (94 %) with complete selectivity after 18 h of reaction at mild temperature (60 °C).