Modification And Catalytic Performance Study Of Catalysts For The Preparation Of Styrene Oxide And Styrene Carbonate

Styrene oxide（SO）and styrene carbonate（SC）are important chemical products,which are both widely used in medicine,chemical engineering,energy,and other fields.However,traditional methods of producing SO and SC are inefficient,and require harsh reaction conditions,producing a large amount of organic wastewater.Therefore,it is of great practical significance to develop a series of highly active and stable heterogeneous catalytic systems for the production of SO and SC efficiently and environment-friendly.It is found that introducing ligands or elements doping are the effective methods to improve the activity of traditional catalysts.Based on it,we adopted a ligand substitution strategy to introduce pyrazine alkyl chain ligands into sodium pentacyanoferrate,and synthesized a series of novel Co Fe Prussian blue analogues（PBA）catalysts containing pentacyanoferrate units for catalytic epoxidation of styrene.The results demonstrate that introducing pyrazine alkyl chain ligands can reduce the crystallinity of the catalyst,improve its hydrophobicity,and regulate its metal valence state.The yield of styrene oxide catalysted by Co Fe-10can reach 70%within 24 hours at 60℃,acheieveing the conversion of styrene to SO effectively.Subsequently,we introduced ligands with C₂ symmetry into the synthesis of Fe Fe PBA.The results indicate that the introduction of C₂ symmetric ligands can effectively maintain the crystallinity of catalysts,and regulate the thermal stability and metal valence of catalysts by changing the type of substituents in the ligands.CH₃-Pyz Fe Fe PBA exhibited excellent catalytic performance,acheieveing 89%yield for styrene carbonate under 100 k Pa CO₂ conditions within 12 hours.Finally,we prepared a sheet-like Co₃O₄ catalyst and synthesized S-Co₃O₄-Ce catalyst by doping Ce element through ion exchange.The results show that the doping of Ce can increase the content of oxygen vacancy and specific surface area of catalyst,thereby improving the catalytic performance.It is obtained the direct conversion of SC from styrene under 12 hours and 100 k Pa CO₂ conditions,with a yield of 40%.