Catalytic N-formylation of amines using CO2 is considered pivotal for the sustainable synthesis of formamides, key chemical feedstocks for synthesizing heterocycles, pharmaceuticals and bioactive molecules. We report a single-site cobalt(II)...
Acetic acid is an industrially important chemical, produced mainly via carbonylation of methanol using precious metal-based homogeneous catalysts. As a low-cost feedstock, methane is commercially transformed to acetic acid via a multistep process involving energy-intensive methane steam reforming, methanol synthesis, and, subsequently, methanol carbonylation. Here, we report a direct single-step conversion of methane to acetic acid using molecular oxygen (O 2 ) as the oxidant under mild conditions over a mono-copper hydroxyl site confined in a porous cerium metal−organic framework (MOF), Ce-UiO-Cu(OH). The Ce-UiO MOF-supported single-site copper hydroxyl catalyst gave exceptionally high acetic acid productivity of 335 mmolg cat −1 in 96% selectivity with a Cu TON up to 400 at 115 °C in water. Our spectroscopic and theoretical studies and controlled experiments reveal that the conversion of methane to acetic acid occurs via oxidative carbonylation, where methane is first activated at the copper hydroxyl site via σ-bond metathesis to afford Cu-methyl species, followed by carbonylation with in situ-generated carbon monoxide and subsequent hydrolysis by water. This work may guide the rational design of heterogeneous abundant metal catalysts for the activation and conversion of methane to acetic acid and other valuable chemicals under mild and environmentally friendly reaction conditions.
Oxidation of alkenes to carbonyls or diols compounds is important in synthesizing fine chemicals and pharmaceutical intermediates. We report the synthesis and characterization of an aluminum metal‐organic framework node‐supported copper(II) chloride (DUT‐5‐CuCl), which is an efficient heterogeneous catalyst for the oxidation of alkenes using H2O2 as an oxidizing agent. Styrene and various substituted styrenes were transformed into the corresponding carbonyl compounds in excellent selectivity and yields. DUT‐5‐CuCl is tolerant with various functional groups and could be recycled and reused at least 5 times in the oxidation of α‐methylstyrene. Unlike the oxidation of styrene derivatives, DUT‐5‐Cu catalyzed oxidation of aliphatic and cyclic alkenes produced 1,2‐diols compounds selectively. The mechanism of the DUT‐5‐Cu catalyzed oxidation of styrene to benzaldehyde was investigated in detail by various experiments such as the determination of reaction intermediates and characterization of the catalyst after catalysis, and computational studies. This work highlights the importance of MOF‐supported earth‐abundant metal catalysts for oxidation reactions to produce fine chemicals.
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