Synthesis Of Amide-derived Functional Materials And Their Application In CO₂ Adsorpyions And Conversion

The chemical utilization of CO₂ is a hot topic in current research,and the efficient conversion of CO₂into cyclic carbonate is one of the effective routes to realize CO₂utilization.However,the current catalytic systems are difficult to possess satisfactory features in terms of catalyst activity and separation at the same time.Based on the above issues,we carried out the following research work.（1）A series of squaramide-functional ionic liquids were synthesized,and their structures were characterized by nuclear magnetic resonance（NMR）,fourier transform infrared rpectroscopy（FT-IR）,mass spectrum（MS）and thermogravimetry analysis（TGA）.The cycloaddition of CO₂to propylene oxide was selected as a model reaction to investigate the activity and recycling performance of the catalysts.By studing the influence of catalyst structures and reaction parameters,a 96%propylene carbonate（PC）yield with 99%selectivity was obtained under the conditions of 1.5 MPa CO₂,100 ℃ with 3 mol%catalyst loading for 3 h,and the catalytic activity was not decreased after reusing for six cycles.In addition,the versatility of the catalyst was investigated,and the developed catalyst could efficiently catalyze the coupling of CO₂with different epoxides.Finally,a possible reaction mechanism was proposed according to the experimental results and related characterization.（2）In order to solve difficult separation problem of homogeneous catalyst,a series of novel squaramide-derived periodic mesoporous organosilica（PMO-TAF）were prepared by a hydrothermal self-assembly method.Their structural features were verified by solid-state NMR,SEM,TEM,XRD,FT-IR,TGA and so on.The obtained materials were applied to CO₂adsorption and catalytic conversion.By adjusting the material structures,the PMO-TAF-20 showed excellent CO₂adsorption capacity of1562μmol/g under a low CO₂pressure,and could also afford excellent PC yield（98%）and selectivity（99%）under the conditions of 90 ℃,1.5 MPa,5 wt%catalyst loading for 7 h.In addition,the PMO-TAF-20 was easily separated,and showed excellent catalyst recyclability.After five cycles,no significant decrease of the catalytic activity was observed.Finally,the versatility of the catalyst was investigated by selecting different reaction substrates and a possible reaction mechanism was provided.（3）On the basis of the previous work,the amide and triazine-derived periodic mesoporous organosilica（TUF-PMO）materials were prepared by the hydrothermal self-assembly method and their structures were characterized.The influences of various TUF-PMO structures on CO₂adsorption and conversion performance were studied.The results showed that the TUF-PMO not only exhibited excellent CO₂adsorption performance which could reach 933μmol/g under low pressure conditions,but also showed high efficiency in catalytic performance.The excellent PC yield（98%）and selectivity（99%）were obtained under the conditions of 90 ℃ with 5 wt%TUF-PMO-20 for 4 h,and the catalytic activity was further improved.At the same time,the catalyst was separated by simple filtration and there was no significant reduction in catalytic activity after five cycles.Finally,the possible catalytic reaction mechanism was revealed.