Study On Preparation Of Cyclic Carbonate Catalyzed By Synthetic Task-special Ionic Liquids

Ionic liquids are liquid salts at room temperature which are composed by anions and cations. Cycloaddition of carbon dioxide and epoxides are catalyzed by the method based on metal compounds and ionic liquids, which not only make catalysts reusably, but also have great significance for the green chemical engineering.Catalyzed coupling reaction of epoxides by salicylaldehyde-amino acid–Metal in ionic liquids was studied. For optimizing the reaction condition, the influence of several factors on reaction was studied, and then a satisfied reaction condition was obtained in 8 hours at 80℃, 4MPa of carbon dioxide with 30 mmol propylene epoxide, 5 mol% salicylaldehyde-amino acid-cobalt, 2 mol% NBu4I and 1 mL [bmim]PF6. In this condition, the conversion and selection of propylene epoxide and propylene carbonate were 90% and over 99%. The substituted epoxides were all catalyzed to the corresponding carbonates through cycloaddition. But the reusability still needed improved.Salicylaldehyde-diamine-Metal was synthesized by changing metal center and structure of complexes in order to study the influence between catalyzed ability and complexes. The molecular structures were confirmed by FT-IR, TGA, EA and NMR, etc. Salicylaldehyde-o-Phenylenediamine/DMAP was satisfied catalytic system by studying the factors on reactions. The substituted epoxides were all catalyzed to the corresponding carbonates. What's more, the catalytic system can be recycled and reused for four runs without any significant loss of catalytic activity.Metal complexes task-special ionic liquids with ionic liquid tags were synthesized in order to improve the catalytic activity of catalytic system. The molecular structures were confirmed by FT-IR, TGA, EA and NMR, etc. It should be noted that the catalytic ability was greatly improved by these Metal complexes task-special ionic liquids. This catalytic system can be recycled and reused for four runs without any significant loss of catalytic activity.Cycloaddition of epoxides and carbon dioxide were catalyzed efficiently by trihexyl (tetradecyl) phosphonium bromide itself, which used not only as catalyst but also as solvent. The system showed high catalytic activity toward the conventional catalysts. What's more, the addition of Lewis acid ZnX2 highly improved the activities of the quaternary phosphonium salts for the cycloaddition of carbon dioxide and propylene oxide.