Heteroatoms Modification Bio-based Carbon And Relevant Applications In Cyclohexane Oxidation

In recent years,metal-free carbon-based catalysts are one of the most active research directions in nanomaterials and catalysis.The advantage that nanocarbon catalysts have over metal catalysts include high efficiency,environmental compatibility and corrosion resistance.Its performance is superior to traditional catalysts in many fields.Today,graphite-based carbon materials,activated carbon,CNTs,mesoporous carbon,and free-metal dropped carbon have a good catalytic effect in liquid-phase oxidation reactions.With the development of green chemistry and fine resources,Synthesis of novel free-metal doped bio-carbon materials and magnetic bio-based carbon materials with biomass have become a new hot spot in the field of catalysis.Therefore,the study on exploring the application of carbon materials in the liquid phase oxidation reaction is of great theoretical and practical significance.In this case,a series of bio-based carbon materials were prepared by using biomass as a carbon source,study its application in the selective oxidation of cyclohexane.The main contents discussed were as follows:(1)Using cellulose as a carbon source,urea and KOH were used to control its structure,and nitrogen-containing carbon nanosheets were prepared by changing the carbonization temperature.The optimum preparation conditions of nitrogen-containing carbon materials were as follows:1 g cellulose,0.12 g urea,0.88 g KOH and 800 ? calcination temperature.Catalyst CKU-800-1:0.12 was used to optimize the cyclohexane oxidation reaction.The amount of TBHP was 8 mol%of cyclohexane,the reaction temperature was 90 ?,the amount of catalyst was 30 mg,and the cyclohexane oxidation reaction was performed for 19 h.The conversion of cyclohexane and the selectivity of KA oil were as high as 7.1%and 100%.Under the optimal reaction conditions of cyclohexane,the content of nitrogen in the nitrogen-containing nanosheets was adjusted by adjusting the urea content.When the mass ratio of cellulose to urea was 1:0.5,the conversion of cyclohexane increased to 9.1%.The catalyst could be reused for 3 times dramatic deactivation.The application of CKU-800-1:0.5 to different alkane oxidation has a better catalytic effect under mild conditions.(2)Bamboo powder as carbon source,using KOH and ferrocene to regulate its structure,by changing the type of graphitized iron source,carbonization temperature,the amount of KOH and other methods to mix the graphitized structure of the material.The optimal preparation conditions of magnetic carbon material:1 g bamboo powder,0.5 g ferrocene,0.88 g KOH and 900 ? calcination temperature.When the magnetic carbon material is modified by melamine and triphenylphosphine,the degree of defect increases with the addition of melamine formaldehyde and triphenylphosphine,and the conversion rate of cyclohexane decreases.Optimum catalyst CBK-Fe-900-1:0.88 cyclohexane oxidation optimization,the amount of TBHP in the substrate cyclohexane 4 mol%,the reaction temperature is 90 ?,the amount of catalyst is 50 mg,cyclohexane oxidation.When the reaction was conducted for 19 h,the conversion of cyclohexane and the selectivity of KA oil was high as 9.1%and 100%.The catalyst was reused for 5 times without significant loss of catalytic activity,however,deactivation was observed after the catalyst was reused for 6 times.