Synthesis of cyclic carbonates from CO2 catalyzed by porous ionic polymers containing phenol pyridine
Phenolated pyridine-based porous ionic polymer(Py-PiP&OH)was synthesized from one step Friedel-Crafts alkylation reaction of 1,4-bis(bromomethyl)benzene,4-phenylpyridine and 2,3-dinaphthol,and characterized by FTIR,XPS,SEM,XRD and TGA.The catalyst obtained were evaluated by N2 and CO2 adsorption-desorption,respectively,for its pore parameters and CO2 adsorption properties,followed by analyses on its catalytic activity,optimal reaction conditions and recycling stability for catalysis on the cycloaddition reaction between epichlorohydrin(ECH)and CO2.The substrate universality of Py-PiP&OH for cycloaddition reaction of epoxide and CO2 was further investigated.The results showed that Py-PiP&OH exhibited a microporous structure with abundant phenolic hydroxyl groups,pyridinium ionic liquid units.The catalyst showed a specific surface area of 155.4 m2/g,and an adsorption capacity for CO2 of 37.1 cm3/g at 273 K and 0.1 MPa.Under the optimal reaction conditions of 25 mg Py-PiP&OH,3.0 mmol ECH,0.05 mL N,N-dimethylformamide,initial CO2 pressure 1.0 MPa,reaction temperature 100℃,reaction time 12 h,the ECH conversion was 99.7%,while the yield of 4-(chloromethyl)-1,3-dioxolan-2-one was 96.3%.Py-PiP&OH could be reused for 5 times without significant loss in catalytic activity and selectivity.When simulated exhaust gas(15%CO2+85%N2,volume fraction)was used as CO2 source,the yield of 4-(chloromethyl)-1,3-dioxolan-2-one could still reach 90.3%at 100℃and 3.0 MPa for 24 h.Moreover,Py-PiP&OH displayed good universality in catalyzing reactions of propylene oxide,propylene oxide bromopropane,1,2-butane epoxide,1,2-hexane epoxide,1,2-octane epoxide,allyl glycidyl ether,phenylethane epoxide with CO2.
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