Study On Light-Driven 2-phenoxyacetophenone Derivative Transfer Hydrogenation And Primary Amine Self-Condensation

As an aromatic ring-shaped biomolecule,lignin can be degraded to obtain high-value-added chemicals and fuels.However,its complex structure,different types of chemical bonds and rich content,which has the disadvantage of being difficult to degrade.To solve this problem,the researchers proposed to use the lignin β-O-4 ketone model synthesized by other means as the research object to expand the degradation of lignin.However,most of the existing research methods adopt metal catalysis and other cracking methods which are not conducive to the development of environment.Because of their special structure,amines can be used as important components of various functional organic molecules.In particular,secondary amines,as intermediates of various reactions,use a large number of reducing substances in the synthesis process,resulting in environmental pollution.In view of the problems of the above two reactions,this paper proposes that under the optical drive,Firstly,transfer hydrogenation of β-O-4 model was achieved with water as H-transfer reagent in the absence of catalyst.Secondly,in the presence of semiconductor catalyst,the synthesis of secondary amine is completed with water as the pushing agent.Both reactions are light-driven,and water is the necessary material for the reaction.It not only reflects the advantages of mild reaction conditions,clean,efficient and environmentally friendly of lightdriven technology,but also uses water as H-transfer reagent or propelling agent,effectively improving the application range of water in the field of chemistry.The main conclusions are as follows:（1）In terms of β-O4 model pyrolysis,the chemical synthesis of 2-phenoxyacetophenone and its derivatives was used as β-O-4 ketone model,and the reduction hydrolysis was carried out.Hydrolysation of 2-phenoxyacetophenone and its derivatives was achieved by using water as Htransfer test under light and no catalyst.Optimize the variable solvent,water content,time,etc.The optimal reaction conditions were as follows:0.5 mmol 2-phenoxyacetophenone,0.2 mL water,2 mL isopropylbenzene,room temperature,30 h.Under the optimal conditions,2-phenoxyacetophenone derivatives can be well hydrogenated into aromatic alcohols and ketones.Water was identified as the only H-transfer reagent by isotope labeling.The hypothesized mechanism is free radical reaction.（2）The target product of primary amine self-condensation reaction is secondary amine.Semiconductor catalyst is used in secondary amine synthesis.In this paper,Pd/g-C₃N₄ is used as semiconductor catalyst,X-ray diffraction,transmission electron microscope projection,UV-diffuse reflection spectrum and Mott-Schottky curve are used to characterize the structure of semiconductor catalyst and draw the energy band spectrum.The variables involved in the reaction,solvent,catalyst type and content and quality,water content,time were optimized.The optimal conditions were as follows:0.5 mmol benzylamine,15 mg 3%Pd/g-C₃N₄,3 mL 1,4-dioxane,5 mL water,reaction for 10 h to get the optimal normalized yield of 99%.The applicability of different substrates shows that the method has good universality.