Preparation And Characterization Of L-proline Immobilized On Solid Materials And Its Application In Asymmetric Mannich Reaction

This thesis was focused on two sections.In the first section,we studied immobilization of L-proline on SBA-15 and its application in asymmetric mannich Reaction.The novel Pro/SBA-15 catalyst was prepared with SBA-15 zeolite as the support to immobilize L-proline derivatives(Pro),which was synthesized from 4-h ydroxy-L-proline.The Pro/SBA-15 catalyst was characterized by X-ray diffraction, N₂ adsorption-desorption,scanning election microscopy,thermogravimetry and infrared spectroscopy.The catalytic performance of the catalyst was measured in asymmetric Mannich reaction.The results indicated that the mesoporous structure of SBA-15 was not affected by the immobilization,however,the pore diameter, pore volume and BET surface area were decreased.The Pro/SBA-15 catalyst had higher catalytic activity and enantioselectivity.Using 4-nitrobenzaldehyde as the reactant,the Mannich reaction product was obtained with high yield(80%)and moderate enantioselectivity(ee=60%).The supported catalyst could be easily separated from the reaction system and reused repetitively without lost activity and enantioselectivity at least for four times.In the second section,we studied synthesis of Pro/FDU catalyst by supported 4-hydroxy-L-proline on FDU phenolic resins.The catalyst was tried to be prepared in four different methods.The Pro/FDU catalyst(Cat-2)which gained from the second method was characterized by X-ray diffraction,N₂ adsorption-desorption. The catalyst was then investigated in asymmetric Mannich reaction and got the equivalent isolated yield with that of Pro/SBA-15 catalyst,but the enantioselectivity was unsatisfied.There is still a lot of work to do in the synthesis of Pro/FDU catalyst.