Preparation And Application Of Nitrile Rubber Hydrogenated Magnetic Catalyst

Hydrogenated nitrile rubber(HNBR)is a highly saturated elastomer by the hydrogenation processing of nitrile rubber.HNBR has better oil resistance than NBR,which has good solvent resistance about fuel oil,lubricating oil,aromatic and so on.The thermostability and chemical resistance of HNBR was be improved,which reduced double carbon bonds through hydrotreating.Meanwhile,HNBR is a kind of rubber with excellent comprehensive performance,which has good performance both of ozone resistance,compressive permanent deformation resistance,high strength,high tear performance and wear resistance.HNBR was obtained by selective hydrogenation of NBR in the industrial solution hydrogenation method with noble metal catalysts..The recovery and utilization of catalysts has always been the research goal of researchers.Ferric oxide particles are unique catalyst carriers because of excellent magnetic(Fe3O4)The magnetic carrier was got by the coating modification of ferric oxide particles,and then the new catalyst can be got by loading the noble metal catalyst.The catalyst can be isolated from the solution through a simple magnetic devices(such as magnets,etc.),which greatly simplified the methods of centrifugal separation.This method not only effectively solved the problem of catalyst recovery,but also optimized the separation method.The preparation of magnetic supported catalyst and selective hydrogenation of NBR were studied.The main research contents of this topic includes the following two aspects:(1)Fe3O4 nanoparticles were generated in situ on multi-walled carbon nanotubes to prepare magnetic carriers for carbon nanotubes.And then rhodium(Rh)nanoparticles loaded on the magnetic carrier catalyst form a new type.of magnetic carbon nanotubes(MWCNTs@Fe3O4@Rh).The structure and morphology of the catalyst were characterized by TEM,XRD and XPS.It can be seen from TEM that the carbon nanotubes are wrapped around Fe3O4nanoparticles with a diameter of 300-400 nm,and the surface was loaded with Rh nanoparticles with a diameter of less than 10nm.The existence of Fe3O4 and Rh particles was also proved by means of XRD and XPS.Meanwhile,the reaction conditions of the catalyst to selective hydrogenation of NBR were investigated.We got the hydrogenation rate of 98.17%of HNBR;and proved that the catalyst of C = C double bond has a good selectivity at 120? 4.0 MPa,for 8 h.The MWCNTs@Fe3O4@Rh catalysts can reach more than 90%hydrogenation,while traditional catalysts have less than 40%after repeated three times.(2)M-SiO2 @ Fe3O4 magnetic carrier was prepared through the procedure,which include Fe3O4 nanoparticles by solvent heat method,silica coating Fe3O4 nanoparticles by the TEOS hydrolyzes under alkaline conditions and APTS modification.The M-SiO2@Fe3O4@Rh catalyst was obtained by adding RhCl3 aqueous solution into dispersed M-SiO2@Fe3O4 magnetic carrier.The hydrolysis mechanism of TEOS and APTS was analyzed and the complexation process of N to Rh ions was described.The structure and morphology of the catalyst were characterized by XRD,TEM,XPS,FT-IR,etc.It can be seen from the TEM that the diameter of Fe3O4 nanoparticles is 300-400 nm,the thickness of the silica layer about 50 nm and the thickness is equal.According to FT-IR and XPS analysis,APTS successfully modified silicon dioxide.The existence of Fe3O4 and Rh particles was also proved by means of XRD and XPS.In addition,the separation effect of catalyst was verified by magnetic separation.We explore the optimal conditions,which achieved the hydrogenation rate of 97.82%of HNBR at 120?,3.0 MPa for 6 h,and to prove that a good selectivity of the catalyst of C=C double bond.The hydrogenation capacity of magnetic catalyst is not lower than that of traditional catalyst after repeated three time,because the unique magnetic properties of the catalyst make separation easy and greatly reduce the separation difficulty.