Prof. Ying-Ming Pan and Hai-Tao Tang research group: advances in research on selective decarbonylation of biomass

datetime: 2019-09-11 views: 55

It is imperative to search for new sources of both transportation fuels and bulk chemicals due to the increasing environmental concerns and urgent shortages of fossil resources.1Biomass-derived sugars are wonderful substitutes for fossil resources due to their structural diversity and abundance.Current strategies for the implementation of biofuels from biomass-derived sugars are mostly directed towards the fermentation of cellulose into bioalcohols or the conversion of biomass-derived sugars into synthesis gas with the subsequent formation of synthetic fuels via a Fischer–Tropsch process.As we all know, biomass-derived sugars are significantly more oxygen rich than those frequently-used chemicals and fuels. Thus, the chemoselective deoxygenation of saccharides is central to the valid utilization of biomass-derived carbohydrate feedstocks.

Porous organic ligands (POLs), a new kind of porous organic polymer (POP) material, can be synthesized through free-radical polymerization routes from the corresponding vinyl-functionalized diphosphine monomers by using an AIBN initiator under solvothermal conditions.Compared with other supports, POLs have attracted attention from many chemists due to their high surface area, large pore volume, hierarchical porosity, superior stability, high efficiency, and excellent selectivity. More importantly, they have been used not only as a solid support but also as a ligand for various metal catalysts.The POLs also can swell in different solvents, and the structure of those swollen polymers could be described as solution. The “quasi-homogeneous” character of metal/POLs makes them have better catalytic activity than the “real homogeneous” catalysts. For example, a series of phosphorus-doped porous organic polymers were used as recyclable catalysts in hydroformylation, isonitrile insertion, and hydrogenation reactions by our group and others. Herein, My laboratory team synthesized a new Pd NP-metalated porous organic ligand (Pd NPs/POL-xantphos)13 as recyclable catalysts for the chemoselective decarbonylation of aldehydes.

This catalyst perfectly overcomes the drawbacks of previously reported methods such as high pressure, low selectivity and the like. Moreover, this heterogeneous catalyst can be reused.. We repeated the decarbonylation of HMF with Pd NPs/POL-xantphos up to 10 times. After each run, the nanocatalyst was recovered via vacuum evaporation and washed sequentially with ethyl acetate, water, and acetone. We were surprised to find that the nanocatalyst could be used for at least 10 runs without losing any catalytic activity. TEM images show that Pd NPs were formed with no notable aggregation after the 10th run