Reducing Amination Of Biomass-based Oxygenates To Produce Nitrogen-containing Functional Molecules

Biomass is the most abundant renewable organic carbon resource on Earth.The use of biomass resources instead of the depletion of fossil resources to produce important chemicals,fuels and functional materials has become a hot global issue.At the same time,the conversion and utilization of biomass has the attribute of"net zero carbon emission",which is one of the important ways to achieve the strategic goal of"carbon neutrality".Based on this,this thesis focuses on the design and screening efficient catalytic systems for the conversion of renewable biomass carbon resources,and the selective conversion of biomass-based oxygenates to produce nitrogen containing functional molecules.The main research contents and novel points are as follows:（1）The direct reduction amination of aromatic ethers（including the typical lignin model compounds）and morpholines was studied using commercial Pd/C as catalyst.The effects of reaction temperature,dosage of catalyst,molar ratio of ether to morpholine,hydrogen pressure and other factors on the reaction were systematically investigated.It was found that Pd/C can catalyze the reduction amination of various aromatic ethers to produce 4-cyclohexylmorpholines without employing any acidic additives.A mechanism study revealed that the desired product was formed via cyclohexanone as the intermediate.（2）The reduction amination reaction of lignin-derived guaiacol with organic amines was studied using commercial Pd/C catalyst.The effects of reaction temperature,molar ratio of guaiacol to amine,dosage of catalyst and other conditions on the reaction were investigated.It was found that Pd/C can catalyze the reduction amination of various guaiacol analogues with different amines to synthesize alkoxy-functionalized cyclohexylamine.The mechanism study showed that the reaction was proceeded by forming 2-methoxycyclohexanone as an intermediate.（3）Nitrogen-doped carbon-supported Co-based catalyst Co@C-N（x）（where x is the pyrolysis temperature）were prepared by the pyrolysis of the metal-organic framework ZIF-67 at different temperatures,which were used as the catalyst to study the reduction amination reaction of carbonyl compounds.It was found that the pyrolysis temperature had a great influence on the activity of catalyst.Co@C-N（800）could efficiently catalyze the reductive amination of various aldehydes/ketones to synthesize the corresponding primary amines with high yields at 35 ^oC.Systematic analysis revealed that the excellent catalytic activity of the catalyst Co@C-N（800）results from the synergistic effect of metallic Co particles and Co-N_x sites.（4）Supported cobalt nanocatalytic material were prepared by in-situ growth an d pyrolysis,using cobalt（II）acetate tetrahydrate and 1,10-phenanthroline as raw materials,for the amination of ketones（especially aromatic ketones）.It was found that the pyrolysis temperature had a significant effect on the catalytic performance of the prepared Co-based catalyst,while the supports had little effect.Among them,Co-Ph@Si O₂（900）prepared at 900 ^oC had the high catalytic activity,which can efficiently catalyze the reduction amination of aromatic ketones at 100 ^oC with a relatively short reaction time（8 h）.Systematic analysis showed that the high activity of Co-Ph@Si O₂（900）is due to the high electronegativity of the metallic Co species and the strong Lewis acidity of the Co-N_x species.