Preparation And Application Of L-lysine Functionalized Polyacrylonitrile Fiber

In recent years,organic molecules are acting as excellent catalysts compared to enzymes and metals.Among them,?-amino acids,which are a kind of natural and environmentally friendly organic molecules,are not only used as the nutrients we human need,but also applied to the catalytic field for their unique structures containing both amino and carboxyl groups.For example,they can effectively catalyze Knoevenagel condensation,aldol reaction,Michael addition and so on.However,these catalytic reactions are difficult to avoid using organic solvents,and organic molecules such as amino acids are difficult to recover and reuse.In order to overcome the shortcomings of small molecule catalysis,the researchers used a variety of substances as supporters,loaded the catalytic ingredients successfully onto the supporters to prepare heterogeneous catalysts that are easy to separate and have good reusability.In this thesis,L-lysine functionalized polyacrylonitrile fiber(PAN_LF)was successfully synthesized by using cheap polyacrylonitrile fiber as the carrier and L-lysine was immobilized onto PAN_LF.The functionalized polyacrylonitrile fiber with good weight gain was obtained by optimizing the reaction conditions.The functionalized polyacrylonitrile fiber was characterized by elemental analysis,FT-IR and SEM,respectively.Finally the structure of the fiber catalyst was proposed based on the determination of sodium ions measured by AAS.The L-lysine functionalized polyacrylonitrile fiber was used to catalyze the Knoevenagel condensation.We firstly studied the effect of the buffer solution of different pH on the catalytic activity of the fiber catalyst.The reaction time,temperature and solvent were also discussed.Then we discussed the effect of the surfactant according to the reaction phenomena.Moreover,the effect of the functionalization of the fiber catalyst on the reaction was investigated.Finally,we studied the scope of the substrate,the reusability of the catalyst and compared the catalytic activity with other catalysts.The experimental results show that the catalytic system has unique selectivity with water as the solvent.The reaction conditions are mild,the operation is simple,and the catalyst is easy to separate and has good reusability.