Synthesis Of Magnetic Catalysts With Core Shell Structure And Their Application In Heck Coupling Reaction

Magnetic nano-catalysts have adwanced advantages compared with other new materials and have widely application prospects in photocatalysis, organic synthesis, environment catalysts, as for their unique magnetic property and nano effect. Specially based on Fe3O4nano particles, nano composite materials with core shell structures, modified by organic or inorganic materials have become one of the excellent candidates for catalyst carrier, its stablabllity and uniform diameter and quasi homogeneous reaction property make it become a hot point research.In this paper we studied the Fe3O4nanoparticles with core-shell as a carrier, and the activity was carried out through the Heck reaction. The preparation of Fe3O4was via modified solvothermal synthesis, and then with soluble starch as carbon source, Fe3O4coated by C was prepared. Through different reduction methods, we load a series of different bimetallic active component. The main research work illustrated as follows:1. C@Fe3O4was synthesized for the first time with soluble starch as carbon source, soluble starch was very common and cheap and has longer carbon chains compared with other carbon source. After carbonized, amount of organic groups was kept on it, which makes it easier for the active component to load onto it. Here we discussed the influences of the reaction time and the concentration of the system on the morphology of the core shell structure, the results shows that when the reaction time was9h, the addition of the soluble starch was5.00g, the as synthesized monodispersed C@Fe3O4has uniform particle size, and the carbon layer was about15-20nm, and has a superparamagnet property.2. A series of M-Pd/C@Fe3O4(M=Cu, Co, Mo, Mn, Zn, Ni) bimetallic catalysts was synthesized via the reduction of diamid hydrate (D), sodium borohydride (B), and hydrogen (H). Their catalytic performance were characterizd and the results show that the catalyst reducted by the borohudride have excellent catalytic activity while its core shell structure kept. The catalyst kept a high catalytic performance under different solvents and different substrates. When Ni and Pd quality ratio of4:1, the activity of catalyst is best. After recycled for6times, the conversion of bromobenzene was above80%and the recovery of the catalyst was above90%.