The Application Of Alcoholamine And Guanidine Catalysts In The Conversion Of Carbon Dioxide Into Quinazolinedione And Cyclic Carbonate

Carbon dioxide chemistry is a research hot topic in chemistry and environmental science.The utilization of CO2 as a feedstock to make chemicals and materials meets the requirement of sustainable development.On the other hand,the transformation of chemically stable CO2 represents a grand challenge in the research of catalysis.Various catalysts were developed for CO2 conversion.Among them,organic base and ionic liquids are efficient and frequently-used catalysts in these reactions.Organic base can catalyze various reactions.Ionic liquids can act as both the catalysts and the solvents in organic reactions for their excellent solubility and tunable properties according to the needs of the reactions.Herein,three catalyst systems,including organic base and ionic liquids,were developed which used in the CO2 chemical transformation for the preparation of quinazolinediones and cyclic carbonates.The concrete research content is as follows:1)Diethanolamine(DEA)was found to be an efficient organic base catalyst for the reaction of CO2 with 2-aminobenzonitrile in water.The reaction proceeded at 100? under 1 MPa CO2 pressure for 12 hours and excellent yield was obtained.Water plays a critical part in the reaction.DEA shows superior catalytic activity resulting from the synergistic effect of hydroxyl and amine groups.According to the result of experimentation,a plausible reaction mechanism has being speculated and evaluated by DFT,FT-IR and 1H NMR spectra.2)Five guanidine-based ionic liquids with different alkyl groups were synthesized by using tetramethylguanidine as a feedstock.It was found that these ionic liquids could act as both the solvent and the catalyst in the reaction of CO2 and 2-aminobenzonitriles to produce quinazoline-2,4(1H,3H)-diones.Ionic liquid with longest substituent groups was the most efficient catalyst in.this reaction.Using[BTMG]OAc as the catalyst,the reaction proceeded at 80 ? under 0.5 MPa CO2 pressure in 24 hours and high isolated yields(up to 90%)was obtained.The Ionic liquid could be reused at least five times without considerable loss in yield.3)We designed a novel hydroxyl-rich ionic liquid based on diethanolamine and served as efficient catalyst in the cycloaddition of CP2 with various epoxides.The reaction proceeded at 120? under 1 MPa CO2 pressure in 3 h.The optimal conditions result in the formation of cyclic carbonate in 99%yields.The hydroxyl groups activated epoxide and showed the synergistic effect with bromine ion in ring-open of epoxide.