Study On Catalytic Performance Of Metal Tetrakis (P-sulphophenyl) Porphyrins Supported Graphene Oxide For Cyclohexane Oxidation

In this study,the cavity of cytochrome p-450 enzyme was simulated using an oxidized graphene as a support for immobilizing metal tetrakis(p-sulfophenyl)porphyrin and forming a biomimetic catalyst.The metal porphyrin was immobilized onto the graphene oxidize by ?-? interaction and hydrogen bond.The catalytic materials were characterized by various spectroscopic techniques.The catalytic performance of the supported metalloporphyrins for oxidation of cyclohexane was discussed and the possible catalytic reaction mechanism was proposed.The main contents of this study are as follows:Graphene oxide,metal tetra(p-sulfophenyl)porphyrins and the corresponding supported materials were prepared by referring some literaures.The catalyst materials were characterized by UV-Vis,FT-IR,TG,BET,SEM and XPS.A single-factor variable method was used to investigate the optimal catalytic reaction conditions for the catalyst.The catalytic performance of the reused catalysts was investigated.The catalysis of cyclhexane oxidation over the catalysts were compared with those of the graphene oxide and unsupported metalloporphyrins.The catalytic results show that,although the oxidized graphene can catalyze the oxidation of cyclohexane but the ability is at a lower level;and honogeneous metal porphyrin catalyst system can not fully develop the catalytic advantages of metal porphyrins.However,cooperation of two single catalysts can show the best advantages of them,offering higher catalytic benifit of cyclohexane oxidation.The graphene oxide immobilized 0.75 mg CoTPPSO3H could be reused 6 times for the cyclohexane oxidation with an average catalyst turnover numbers of 7.51 ×105.the corresponding MnTPPSO3H could be reused 6 times for the oxidation with an average catalyst turnover numbers of 6.87×105.although the corresponding FeTPPSO3H could be reused 6 times for the cyclohexane oxidation,it could only provide with an average catalyst turnover numbers of 4.94×105.So the catalytic activity order of three catalysts are CoTPPSO3H/GO>MnTPPSO3H/GO>FeTPPSO3H/GO.Based on experimental data and some literatures,it is presumed that oxidation of cyclohexane over metal tetra(p-sulfophenyl)porphyrin may be free radical reaction.