Selective Synthesis Of Secondary Amines Catalyzed By Platinum Nanowires

Catalysis is the foundation of our modern chemical industry, which has been widely applied in medicine, food, chemical engineering and environment protection. However, some problems still need to be solved in current catalysis technology, such as inefficiency, serious corrosion and environment-unfriendly. With the development of the nanotechnology, catalysis faces new challenges and opportunities. Nanoparticles always have smaller diameters and larger surface areas. These unique effects will speed up the reaction rate, raise the reaction efficiency, even make the reaction happens which is hardly carried out before. However, these effects still can lead to many problems, such as aggregation, component loss and recyclable.Nanowires as one of one-dimension nanomaterials have attracted many researchers attention as their highly ordered crystal structures since1990and developed rapidly in the next twenty years. Compared with nanoparticles, nanowires still have higher catalytic activity as they keep small size effect (the diameter is nano scale). Nanowires can be separated from reactions easily as their macro-characteristics like bulk materials (the length is micro scale). When nanowirs were used as the catalysts, no supporter was needed and we can make good use of the active sites of the catalysts.This thesis is on the basis of studying on new nanowires, and select the suitable reaction conditions to get a high activity and selectivity catalytic system. This will be a supplementary for the traditional catalytic systems. The work includes the following three aspects:(1) The ultra-thin Pt nanowires were synthesized with controllable structures, components, and characterized by TEM, XPS, XRD etc.(2) A facile and efficient method for the synthesis of secondary amines through directe reductive amination of aldehydes or ketones with ammonia has been developed using unsupported Pt NWs under mild conditions. The activity of the Pt NWs in different solvents, temperatures and molar ratios of aldehydes to ammonia had been investigated. (3) Hydrogenation of nitriles and catalytic coupling of nitriles with primary amines to form secondary amines have been achived using unsupported Pt NWs under mild conditions. Symmetrical and unsymmetrical secondary amines can be obtained with this catalytic system in good yield.