Preparation Of Nitrogen-rich Organic Polymer PCTs And Their Catalytic CO₂ Cycloaddition Reactio

Although the increase of CO₂ emissions poses a threat to the environment year by year,CO₂ is also a cheap and abundant renewable C1 resource as the main greenhouse gas.Therefore,in recent years,the focus of CO₂ research has gradually shifted from adsorption and removal to conversion and utilization.Among many conversion and utilization methods,the cycloaddition reaction of CO₂ and epoxide has received so much attention.First of all,the reaction has 100%atomic economy and conforms to the concept of green chemistry.Secondly,cyclic carbonate which produced by cycloaddition reaction has been used in many fields such as electrolytes and non-toxic solvents.Therefore,the conversion of CO₂ into cyclic carbonate has good prospects.However,due to the inert nature of CO₂,how to develop efficient catalysts has become the focus of the cycloaddition field.In recent years,hydrogen bond donor（HBD）structures（such as-OH,-NH₂,-COOH,etc.）have attracted attention due to their role in polarizing epoxide and promoting ring opening reactions.And nitrogen rich organic polymers with a large number of hydrogen bond donor structures are gradually entering the researchers’field of vision.In this paper,Nitrogen-rich organic polymer poly（chloride triazole）（PCTs）was synthesized by an one-step method as metal-halogen-free heterogeneous catalyst for the solvent-free CO₂ cycloaddition.PCTs had abundant nitrogen sites and hydrogen bond donors,exhibited great activity for the cycloaddition of CO₂ and epichlorohydrin,and achieved 99.6%yield of chloropropene carbonate under the conditions of 110℃,6 h,0.5 MPa CO₂.The activation of epoxides and CO₂ by hydrogen bond donor and nitrogen sites was further explained by density functional theory（DFT）calculations.In summary,this study showed that nitrogen-rich organic polymer is a versatile platform for CO₂ cycloaddition,and this paper provides a reference for the design of CO₂cycloaddition catalysts.