Synthesis Of Zinc Based Ionic Liquids And Catalysis For CO₂ Cycloaddition Reaction

The conversion of CO₂ into cyclic carbonates is one of the important ways to reduce the content of CO₂ in the atmosphere.A large number of non-homogeneous catalysts,supported by porous materials have been developed.Although they can selectively adsorb gas phase molecules,they have a series of problems such as harsh reaction conditions and easy leaching of the supported materials.The development of catalysts for efficient CO₂ fixation under mild conditions is a long-term goal of many researchers.The synergistic effect of Lewis acid-base pair is crucial to the chemically fixed CO₂ cycloaddition reaction.Scientists are committed to the development of catalysts and have not yet thoroughly explored the impact of changes in the content of each component on the performance of catalysts.The Lewis acid-base pair synergy is critical to the chemically fixed CO₂ cycloaddition reaction.To explore the effect of Lewis alkaline site content change on the catalytic activity of catalysts,urea was introduced to zinc-imidazole ionic liquid as the substrate to significantly increase the Lewis base（-NH₂）content and to synthesize Lewis acid/base urea-[（CH₂CH₂OH）Mim]ZnBr₃,as measured by FT-IR,TG and GC.And under mild conditions（80℃,1.5 MPa）,the conversion rate of propylene oxide was higher than 95% after 6 hours of reaction.At the same time,the catalyst in carbon dioxide and other series of epoxide coupling universality in catalytic reaction,catalytic experimental results with existing characterization analysis,put forward reasonable catalytic reaction mechanism.The experimental results show that the introduction of urea provides a large number of Lewis base functional groups（-NH₂）,which can significantly improve the catalytic effect of the reaction between CO₂ and epoxide to synthesize cyclic carbonate.Which is result of that a large number of Lewis alkali active sites enhance the interaction between catalyst and CO₂ molecules,promoting the adsorption and activation process of CO₂.In order to explore the influence of the change in the component content of Lewis acid on the catalytic activity of the catalyst,ZnI₂ was introduced to improve the content of Lewis acid(Zn²⁺)on the basis of ionic liquids derived from urea,and the two-component catalysts of Lewis acid and base were synthesized.Explore and determine the basic experimental conditions and experimental steps.The catalyst in carbon dioxide and other epoxide as a substrate for the applicability of the cycloaddition,different reaction parameters,such as reaction temperature,the amount of carbon dioxide reaction pressure,reaction time,catalyst for UDIL-I-ZnI₂ carbon dioxide and epoxide catalyzed coupling to generate the influence of cyclic carbonate catalytic activity,and possible catalytic reaction mechanism is put forward.The results showed that with the increase of Lewis acid content,the activation rate of epoxides was significantly increased and the reaction temperature was reduced.Satisfactory epoxides conversion rate and catalyst selectivity were still obtained.The PC yield was up to 95% after 6 h reaction at 80℃ and 1.5 MPa.