Synergistic Lewis acid and Pd active sites of metal-organic frameworks for highly efficient carbonylation of methyl nitrite to dimethyl carbonate

• Published in: Inorganic chemistry frontiers Vol. 9; no. 1; pp. 2379 - 2388
• Main Authors: Wu, Han-Ying, Qin, Ye-Yan, Xiao, Yi-Hong, Chen, Jian-Shan, Guo, Rong, Wu, Si-Qi, Zhang, Lei, Zhang, Jian, Yao, Yuan-Gen
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 24.05.2022
• Subjects: Acids; Carbon monoxide; Carbonyls; Catalysts; Composite materials; Electron density; Inorganic chemistry; Lewis acid; Metal-organic frameworks; Palladium; Selectivity; Synergistic effect
• ISSN: 2052-1553; 2052-1545; 2052-1553
• DOI: 10.1039/d2qi00302c

Metal-organic frameworks (MOFs) have recently been applied as versatile platforms for constructing efficient catalysts with improved performance in many fields. Herein, for the first time, we prepare a MOF UiO-66 based catalyst showing the synergistic effect of Lewis acid and Pd( ii ) active sites, and it shows highly efficient methyl nitrite (MN) carbonylation to dimethyl carbonate (DMC). Lewis acid sites were first introduced to UiO-66 by adding different amounts of trifluoroacetic acid (TFA) and activating at different temperatures. Pd( ii ) sites were then supported on UiO-66 x - X to obtain the resulting Pd-UiO-66 x - X ( x , the molar percentage of TFA; X , activation temperature). The Lewis acid sites not only act as the center of CO adsorption, but affect the electron density of Pd( ii ) for the generation of more COOCH 3 * intermediates, resulting in a higher catalytic performance. As a result, the best catalytic performance based on the DMC selectivity based on CO ( S DMC/CO ) near 100%, S DMC/MN up to 67.4%, CO conversion to DMC ( C CO ) as high as 68.4%, and the weight time yield (WTY) of DMC up to 2056 g kg cat −1 h −1 was achieved by the composite material Pd-UiO-66 TFA-0.25 -290. This work provides efficient catalysts for carbonylation of MN to DMC and presents a significant synergistic methodology for improving the catalytic performance of MOF materials. We for the first time systematically investigated a MOF UiO-66 based catalyst showing the synergistic effect of Lewis acid sites and Pd( ii ) for highly efficient methyl nitrite (MN) carbonylation to dimethyl carbonate (DMC).