Research Of Catalytic Hydrodeoxygenation Of Sulfoxides And Aromatic Ketones By Non-noble Metal Catalysts

Catalytic hydrogenation is the essential step in chemical production and scientific research,including the reduction of the unsaturated groups,hydrocracking,hydrodeoxygenation,hydrodesulfurization,etc.,and it has a wide range of applications in various fields.Taking hydrodeoxygenation reaction as an example,traditional method needs to use the noble-metal catalytic systems and the stoichiometric toxic reductants,with the production of waste.Due to the abundant reserves and low prices of non-noble metals,it is of great significance to develop non-noble metal catalytic systems for hydrodeoxygenation reaction.In this paper,two kinds of heterogenous non-noble metal catalysts were prepared,and they were applied to a variety of the hydrodeoxygenation reactions of unsaturated functional groups.The structure,morphology and chemical states were analyzed by characterization methods such as XRD,TEM and XPS,etc.The mechanism of catalytic reaction was revealed by exploring the structure-activity relationship between catalyst structure and catalytic efficiency.Since no toxic reducing agent is used in this catalytic system,the by-product is only water,which is in line with the principle of sustainable development and the concept of green chemistry.The main research contents are as follows:（1）A kind of non-noble and heterogenous nitrogen-doped carbon supported Ni nanoparticle catalyst（Ni/NC-600）was prepared,and was applied to the catalytic dehydrogenative coupling of primary amines and the in-situ hydrodeoxygenation of sulfoxides.Also,the reaction was atomic efficiently.The results showed that:after the reaction which was carried out at 170°C under 10 bar N₂for 15 h in the solvent of n-hexane,the conversion of diphenyl sulfoxide and benzylamine reached>99%,and the products were N-benzylidenebenzylamine and diphenyl sulfide.The developed catalytic system showed good tolerance to other functional group substituted substrates,and the selectivities of different imine and sulfide substrates were greater than 99%.This catalyst showed good stability,and the activity did not decrease significantly after 5 cycles.In this catalytic reaction system,two kinds of high value-added chemicals were obtained（imines and sulfides）,and the molecular hydrogen was derived from the dehydrogenative coupling of primary amines,and was used as the hydrogen source of the hydrodeoxygenation of sulfoxides.No additional hydrogen source was needed in this catalytic system,and the only byproduct was H₂O,which is environmental-friendly.（2）A metal oxide/nanoparticle composite catalyst（Co/Co O-V-350）was prepared by the vacuum pyrolysis method,and showed good activity for the hydrodeoxygenation reaction of ketones.The reaction was carried out for 13 h under100°C,10 bar H₂in the solvent of toluene.The conversion of acetophenone and the selectivity of ethylbenzene could both reach>99%.According to the characterization,abundant oxygen vacancies exist in the catalyst,which can selectively adsorb and active the oxygen atom containing groups,which lead to the concentration of the substrate on the surface of the catalyst.In the meanwhile,the reaction barrier for the cracking of C=O bonds was lowered greatly and the reaction efficiency was increased.In other hands,Co nanoparticles can activate H₂molecular,promoting the hydrodeoxygenation reaction.The catalyst also has high activity for the hydrodeoxygenation reaction of sulfoxide compounds and the reductive coupling reaction between nitro compounds and aldehydes,which can produce sulfide compounds and imine compounds with high selectivity,respectively.The catalyst shows high activity after 5 cycles,which can be used repeatedly.