School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China;School of Chemistry and Chemical Engineering,Queen's University Belfast,Belfast,BT9 SAG,UK;Eco-Efficient Products and Processes Laboratory (E2P2L),UM13464 CNRS-Solvay,Shanghai 201108,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China;Laboratory for Membrane Materials and Separation Technologies,Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China
Abstract:
The aerobic oxidation of monoalcohols and diols to acetals is an important academic and industrial challenge for the production of fine chemicals and intermediates. The existing methods usually rely on a two-step process in which alcohols are first oxidized to aldehydes over metal catalysts (Ru, Pt, Pd) and then acetalized using acids. Due to the instability of aldehydes, how to avoid over-oxidation to their respective carboxylic acids and esters is a long-standing challenge. For this reason, certain non-conjugated dialdehydes have never been successfully produced from diol oxidation. Hereby we report a Ru@metal-organic framework (MOF) tandem catalyst containing ultra-fine Ru nanoparticles (< 2 nm) for direct alcohol to acetal conversion of monoalcohol and diols with no formation of carboxylic acids. Mechanistic study reveals that the presence of Lewis acid sites in the MOF work in concert with Ru active sites to promptly convert aldehydes to acetals thereby effectively suppressing the formation of over-oxidation byproducts.
