Study On Synthesis Of Guanidine Ionic Liquid Catalysts And Their Application In Catalytic Henry Reaction

The Henry reaction is a classical and atom economical C-C bondforming reaction in synthetic organic Chemistry,the resultingβ-nitroalcohols are highly valuable synthons for the preparation of usefulintermediates in synthetic organic chemistry. The study of catalysts ofHenry reaction has received attention from researchers However, most ofthese methods suffer from some limitations, such as relatively high catalystloading, long reactive time, and poor recovering and reutilization. To solvethe problem, there is still scope for development of highly effective andreusable catalysts. Based on our former work, we designed and synthesizedtwo novel series of catalysties. a series of silica-supported ionic liquidimmobilized guanidinium salts were developed and applied to Henryreaction. Their catalytic properties have been studied by applicating thesecatalysts in Henry reaction. and on this basis, the recycle of catalysts havebeen studied. A kind of chiral guanidinium salts ionic liquid have beensynthesized, Discusses the stereo selectivity in Henry reaction.1. Guanidinium halide ionic liquids were syhthesized from1,1,3,3-tetramethylguanidine and alkyl halide. The guanidinium-based ionicliquids with different anions were obtained by methathesis reaction of theguanidinium halide ionic liquids. All of the above mentioned compoundswere characterized by1H NMR,13C NMR and Ms. The catalyticperformance of these guanidinium-based ILs were investigated. The resultsshowed that guanidinium acetate ILs provided preferable catalytic activityin Henry reaction. the isolated yield reached93.9%.At last, the catalystscould be easily recovered and reused6times without significant loss ofactivity.2. Supported on the surface of modified silica gels with a monolayer ofcovalently attached ionic liquid have been synthesized and characterized,then explored their catalyze ability and effect in the Henry reaction. Theinfluence of reaction medium, reaction time, the structure of catalyst andthe molar ratio of substrate to catalyst on the catalytic activity have beeninvestigated. The study of recycle of catalyst has been researched on theoptimized conditions.The results have demonstrated that the silica-supported ionic liquid immobilized guanidinium acetate salt hasshown the highest catalytic activity in Henry reaction, the isolated yieldreached93.9%. Moreover, the catalyst can be recovered by simplesolid-liquid separation and reused over six times with unchanged catalyticproperties.3. The chiral guanidinium salts ionic liquid were synthesized with L-tartaric acid,L-menthol used as raw material． Their sructures werecharacterized by MS，IR,1HNMR，and specific rotation． unexpectedly,thechiral β-amino alcohos were found not to be efficiency in asymmetric Henryreaction,the enantiomeric excesses were only5.0％． This application needto be found in further research．...