Preparation Of Magnetic Catalyst Support With Core-shell Structure And Application For Synthesis Of Diphenyl Carbonate

Diphenyl Carbonate (DPC) is an important raw material for producing generalengineering polycarbonates.There are four main synthetic process to preparation DPC:phosgene method, transesterificaton, decarbonylation of diphenyloxalate and oxidativecarbonylation of phenol, the direct synthesis of oxidative carbonylation of phenol todiphenyl carbonate method has a short reaction process and high atom effiecncy,meanwhile, it is friendly to the environment, thus it has become the hot topic in all overthe world.For the direct synthesis of DPC with oxidative carbonylation, more attention is onthe study of the choice of catalytic system, including homogeneous catalyst andheterogeneous catalyst, less study on the reactor. Most catalytic reaction was occured in afixed bed reactor or slurry bed reactor, it had an uneven mass transfer, meanwhile, thesynthesis reaction of DPC with oxidative carbonylation is an strong exothermic reaction,it is easy to occur local t-emperature runaway and channeling. In order to solve aboveproblems, we attempt to apply the magnetically stabilized bed (MSB). The research workinvolved two points: the one was the design and prepararion of magnetic catalysts, theother would investigated the catalytic activity and optimize the reaction conditionsthrough the reaction of the synthesis of DPC with oxidative carbonylation.In this paper, DPC was synthesized by magnetic catalyst support with core-shellstructure and Pd was used as the active component. The design and preparation of themagnetic core, the method of the coating, metal doping within support, the synthesisprocesses of supports and catalysts were studied. The activity evaluation of catalyst wasbased on the synthesis experiments of DPC. The support and catalysts were invetigatedin XRD, BET, TEM, VSM techniques. The possible catalytic mechanism was discussed.Meanwhile, the reaction conditions was also studied subsequently. The correlativeconclusions were listed as below:(1)Among different sifting and preparation of the magnetic core, Fe3O4@SiO2hadbetter morphology control and magnetism. (2)The optimal calcinations temperature of support was at550℃, and while themolar ration Ce and Mn was1:1, the support present a obvious core-shell structure, thecatalyst Pd/Fe3O4@SiO2@Ce1-xMnxO2had the better activity with a DPC yield of14.4%.(3)The proportion and doping method of CuO had an impact on the activity ofcatalyst. When the9wt%Cu(NO3)·3H2O-was added to the solution-directly, the catalysts-had better catalytic activity with a DPC yield of20.67%, while the supportFe3O4@SiO2@CuO-Ce0.5Mn0.5O2had a specific saturation magnetization of21.5emu/g.The support presented a good paramagnetism and could meet the demands of themagnetically stabilized bed reactor.(4) The reaction time, temperature and pressure had an impact on the yield of DPC.The optimum reaction conditions were reaction temperature100℃, reaction time6h, andtotal pressure6MPa(7%O2). The yield of DPC could reach23.84%...