Study Carbon Species In The MTO Reaction And CeO₂/mesoporous Carbon Materials With¹³C Solid State Nuclear Magnetic Resonance(SSNMR)

Light olefins and imide have a huge influence to human life.The former is mainly used to produce styrene,vinyl chloride,acrylonitrile etc.C=N double bond in the imine is highly electrophilic.Thus nucleophilic reaction can occur effectively.The derivatives produced from imide,have been widely used in the pharmaceutical synthesis,pesticide synthesis,fine chemical industry and other fields.In this study,the carbon species generated in the process of MTO and ceria-carbon composite catalysts for imine synthesis are carefully investigated with 13C solide-state NMR spectroscopy.The main research results are:1?The effects of different Si/Al ratios of the HZSM-5 on the methanol to olefins(MTO)reaction have been studied.Br?nsted acidic sites increase with decreasing Si/Al ratio of the HZSM-5.12CH3OH/13CH3OH switching was used provide the details of the carbon species over a certain period of time on different Si/Al ratios of HZSM-5.The expansion of the five or six membered ring,along with the condensation and alkylation of aromatics,occurs on the aluminum rich HZSM-5 initially,because of more Br?nsted acidic density.However,the activity of alkylation of aromatics is significantly reduced due to carbon deposition.On the contrary,alkylation of aromatics is the main reaction occurring on the HZSM-5 with higher Si/Al ratio.2?A modified hard-template method was used to prepare CeO2/mesoporous carbon catalyst(CeO2/MC).The material shows high conversion efficiency and good selectivity to produce imide for catalytic alcohol amine dehydrogenation/oxidative coupling.By applying 1H?13C CP MAS NMR combined with 1H MAS NMR,the interaction between the mesoporous carbon materials and cerium oxide is investigated.The results show that the OH species on the surface CeO2 interacts with the ester groups of MC.The richer functional groups surrounded CeO2 helps to improve the performance of the catalytic reaction.