Synthesis Of Magnetic Biochar Catalysts And Their Catalytic Performance For Organic Reactions

With the idea of green chemistry is gaining in popularity,looking for a green catalyst support material has become the target of some chemists.Biochar is a high-carbon,fine-particle,porous material obtained by firing biomass raw materials in airtight space with little air.Its wide variety of sources of biomass materials such as wood,animal dung or other crop residues,etc.Biochar is widely used in agriculture and environmental engineering.Biochar can maintain the nutrition of the land and increase the crop yield.It can also be used as a carrier for carbon fixation or remove the heavy metal ions and organic pollutants in water by its excellent adsorption performance.Biochar,as a new green porous material in recent years,has drawn more and more attention for its superior adsorption performance and stability.Taking biochar as carrier,loading different performance catalysts or modifying different active groups and applying it to organic chemical reactions has gradually garnered significant attention.Therefore,this paper uses orange peel to prepare three different types of biocoke catalysts for biomass:Fe₃O₄@OP@SO₃H,Fe₃O₄@OP@Mg,Fe₃O₄@OP@DBU and apply them to the synthesis of pyrazolopyridine derivatives pyrazoloquinoline derivatives and piperidin derivatives as a series of reactions.The properties of these three catalysts were elaborated in detail through a series of characterizations.The catalytic performances and the applicable ranges of the three catalysts under different conditions were fully investigated.An effective process is developed for synthesis of pyrazolopyridine derivatives via one-pot,three-component reaction of pyrazole amine,eosin and?-ketonitrile in ethanol under microwave heating condition catalyzed by Fe₃O₄@OP@SO₃H.The catalyst Fe₃O₄@OP@SO₃H showed high catalytic activity.The reaction time is greatly shortened due to the use of microwave heating,and the post-treatment method was simple and the catalyst recovery was convenient.In the synthesis of pyrazoloquinoline derivatives,this work synthesized pyrazole amine and 2-hydroxy-1,4-naphthoquinone or 4-hydroxycoumarin or 1,3-indan dione.The reaction was also in ethanol under microwave heating condition.The influence of diverse substrates on this reaction was explored and many different types of products were synthesized.In this paper,the catalyst Fe₃O₄@OP@DBU was prepared by the use of an organic base DBU connected to biochar.The scope of application of this type of catalyst has been broadened through the improvement and modification,this type of reaction rate is greatly accelerated,the yield is increased.A series of tetrahydropyranopyridine derivatives,hexahydropyridopyrimidoindazole derivatives,hexahydropyrimidonaphthyridine derivatives,hexahydropyridotriazolopyrimidine derivatives were synthesized by using this catalyst.