Study On The Catalytic Performance Of Amine-modified Sugarcane Bagasse

Catalyst plays an important role in organic synthesis.Especially solid catalysts,which can be reused and separated from products and continuous production easily,have been widely studied in recent years.Bagasse is a promising natural polymer functional material with abundant sources,renewable,degradable and environment-friendly.Its surface contains a large number of active groups,and it is stable in most organic solvents.This is an ideal support for solid catalyst preparation.The design and construction of catalyst based bagasse is of great significance in promoting the high value utilization of bagasse and biomass materials,alleviating the dependence of traditional carrier materials on petrochemical resources,environmental pollution and promoting the sustainable development of society.In this thesis,two types of catalysts,amino functionalized bagasse and amino functionalized bagasse supported nano-palladium,were prepared and applied to various organic synthesis reactions.The specific contents are as follows:?1?Amino functionalized bagasse catalyst?SCB-NH₂?were prepared by two step reaction with 3-chloropropyltrimethoxysilane as coupling agent,ethylenediamine as functionalized reagents.The structure,thermal stability,morphology and elemental composition of the catalyst were characterized by FT-IR,XRD,TG,SEM-EDX and elemental analysis.The catalytic performance of the catalyst in solvent free Knoevengel condensation was investigated.The results showed that the catalyst had high catalytic activity,especially for the Knoevengel reaction of aromatic aldehydes and propyl two nitriles.The reaction time was short,and the target yield reached 85?98%.After simple post-treatment,the catalyst was reused.After 6 cycles,the decrease of the activity was not obvious.?2?The Knoevenagel condensation reaction of benzaldehyde and malononitrile was studied bybatch method and continuous flow method with SCB-NH₂ as a catalyst.On the basis of batch reaction,a column continuous flow reactor was designed.The results show that the catalytic performance of catalyst in continuous flow reaction is better than that in batch reaction.The mixture of benzaldehyde and malononitrile continuously flow through the chromatography column at the flow rate of 1.5mL/min.After 80h,the conversion and selectivity are above 98%and 99%respectively.After 85h,the conversion rate begins to decrease slowly.The product is obtained after simple removal of the solvent,and the purity is more than 99%.Furthermore,the recovered catalyst was characterized by FT-IR,XRD,TG,SEM-EDX and elemental analysis.It was found that the structure of bagasse as catalyst support was stable in the reaction system.While the catalyst activity decreasing was due to the active-NH₂ groups lost.The continuous flow reaction method is easy to be operated,and the catalyst can be separated from the product directly.It is environmental friendly and has a good industrial application prospect.?3?The Knoevenagel condensation reaction of platform chemicals based biomass withmalononitrilewas studied by the batch and continuous flow methods,using SCB-NH₂ as a catalyst.On the basis of the batch reaction,a continuous flow reactor in the HPLC system was designed.Furfural and malononitrile are continuously flowing through the HPLC column packed with catalyst at 0.75 mL/min flow rate.The reaction time kept for 60 h,and the conversion and selectivity are all above 98%.After 70 h,the conversion rate decreases.The product is obtained after simple removal of the solvent,and the purity is more than 99%.This method is easy to industrialize and pollution-free.Furfural and ethanol are all important platform chemicals based biomass,and catalysts are also prepared based on modified bagasse.These are effective methods for high value utilization of bagasse and other materials based biomass.?4?A series of 2-amino-4H-chroene derivatives were prepared by series reaction of aromatic aldehyde,malononitrile and 1-naphthol with SCB-NH₂ as catalyst.Firstly,the effects of catalyst dosage,solvent,reaction time and temperature were investigated with the reaction of benzaldehyde,malononitrile and 1-naphthol as templates.The optimum reaction conditions were obtained,and the yield of target products reached 81%.On this basis,12 different kinds of 2-amino-4H-alkene derivatives were prepared with different substituted aromatic aldehydes.The yield was 75?95%.The catalyst was reused 4 times,and the decrease of the activity was not observed obviously.?5?The catalyst of nano palladiumsupported amino functionalized bagassewas prepared with amino functionalized PdCl2 and bagasse as raw material,95%ethanol as solvent and reducing agent.The catalysts were characterized by SEM-EDX,TEM,XRD,FT-IR,XPS,TG and other methods.The application of the catalyst in the coupling reaction of Suzuki was studied.The results showed that the catalyst can efficiently catalyze the coupling reaction of aryl bromidesand aryl iodides with phenylboronic acid.The yield of target products is 80 to 98%,but the catalytic activity for aryl chlorides is low.After repeated use of the catalyst for 6 times,the decrease of the activity was not obvious.To summarize,amino-functionalized bagass and the related nano-Pd supporting catalysts have the excellent catalytic performance.These studies can provide good preference and ideas for the utilization of biomass resources.