Preparation And Properties Of NaY Zeolite Modified And Immobilized Iionic Liquid Catalyst

The rapid development of industrial economy brought the rapid increase of CO₂emissions,the cause of the greenhouse effect has become a global attention hotspot.The catalysts catalyze carbon carbonate with carbon dioxide as cycloplus reaction is an atomic economic reaction and meets the requirements of double carbon strategy.However,the ionic liquid limits its further industrial application due to its own phase state and viscosity.Therefore,The search for new supports to prepare efficient immobilized ionic liquid catalysts has attracted the attention of experts and scholars.The main contents of this study are as follows.First,in order to enhance the acidity of the Na Y zeolite and improve the catalytic effect,and through ion exchange process under different reaction temperature Na Y zeolite was modified into HY zeolite,The infrared structure,crystal structure and specific surface area of Na Y zeolite and HY zeolite were tested.The two zeolite catalytic CO₂and propylene oxide huansheng into propylene carbonate,Under the conditions of temperature 110℃,constant pressure of CO₂1.5Mpa,reaction time 2.0h,and dosage of zeolite accounts for 2.0%of propylene oxide by mass,Na Y zeolite and HY zeolite have catalytic effect on the synthesis of Propylene carbonate,however,HY zeolite is more acidic and has a better catalytic effect,epoxy oxide conversion,product selectivity and yield can reach 31.60%,21.98%and 6.95%.Then,N-methimidazole,haloalkane and zinc bromide were mixed by one-step method,and stirred at 80℃for reflux and reacted for 24h to prepare compound salt ionic liquid[BMIM]Br/（Zn Br₂）₂and[He MIM]Cl/（Zn Br₂）₂,Then respectively immobilized onto HY zeolite,the preparation of the immobilized ionic liquid catalysts HY-[BMIM]Br/（Zn Br₂）₂and HY-[He MIM]Cl/（Zn Br₂）₂,The infrared structure,crystal structure and specific surface area of the two catalysts were tested.The catalysts HY-[BMIM]Br/（Zn Br₂）₂and HY-[He MIM]Cl/（Zn Br₂）₂were used to catalyze the synthesis of CO₂and propylene oxide,respectively,to compare the catalytic properties of the two immobilized ionic liquids,The results show that the catalytic effect of HY-[He MIM]Cl/（Zn Br₂）₂is better than that of HY-[BMIM]Br/（Zn Br₂）₂,which is due to the strong acidity of HY molecular sieve,This is due to the strong acidity of HY zeolite,and the hydroxyl group of[He MIM]Cl/（Zn Br₂）₂forms a synergistic catalysis with HY zeolite,which is more conducive to the catalytic reaction,the epoxy propane conversion,selectivity and yield of the product are increased to more than 89%.However,its cycling performance is poor and there is obvious unloading phenomenon.Finally,In order to better solve the problem of component loss,HY-CPTES zeolite is formed from 3-chloropropyl triethoxysilane（CPTES）and HY zeolite.and then reacted with[He MIM]Cl/（Zn Br₂）₂to prepare silane coupling of molecular sieves immobilized ionic liquid catalyst HY-CPTES-[He MIM]Cl/（Zn Br₂）₂,and its infrared structure,crystal structure,specific surface area and other measurements.The catalyst has been used in the kettle catalytic reaction of carbon dioxide and propylene oxide to propylene carbonate.The effects of reaction temperature,reaction pressure and recycling times on catalytic performance have been investigated.The results show that the catalyst is best at 2.0%of propylene oxide mass,pressure of 2.0MPa and temperature of 130℃,epoxy oxide conversion,product selectivity and yield can reach 95.21%,90.34%and 86.01%.The results showed that the conversion rate,selectivity and yield of the double salt ionic liquid catalyst supported by silane molecular sieve could still reach 80.92%,85%and 68.78%after eight cycles.Above all,to some extent,silane coupling agent enhanced solid chemical bond can be immobilized ionic liquid catalyst,improve the stability of catalyst,the easing of immobilized ionic liquid catalyst active component loss phenomenon.