Theoretical Study On Catalytic Oxidations Of Methane To Methanol By Manganese Corrole

Metal corrole complexes are endowed with brilliant catalytic activity and always used to catalyze the oxidations of organic compounds.Methanol,as a desired product for the conversion of methane,has broad application prospect.In order to find a new method for methanol synthesis from methane in one step and provide theoretical basis for the experiment,the catalytic oxidation of methane to methanol was calculated.Simultaneously,the oriented external electric fields（OEEFs）can be used as"invisible catalysts"to regulate chemical reactions,which has been applied in a number of reactions.The influence of catalytic oxidation of methane to methanol by OEEFs were calculated to study its catalytic effect,which provided reference for application research of OEEFs.Herein,calculations was performed using the B3LYP-D3 hybrid functional implemented in Gaussian16 package.Through the study,it is speculated that the reaction contains both Mn-O-O oxidation and Mn（V）-oxo oxidation.Firstly,Mn-O-O corrole with oxidative activity can be obtained by the interaction of Mn-corrole and O₂.The terminal group O of Mn-O-O corrole extracts a hydrogen atom of CH₄,and then through the rebound reaction,hydroxyl group returns to the substrate immediately to obtain CH₃OH and Mn（V）-oxo corrole.Similarly,Mn（V）-oxo corrole also has a good oxidizability.happening spin-flip and then the oxidation reaction proceeds through the potential energy surface of quintet states in the reaction process.Hydrogen was also extracted to form the intermediate of methyl radical（CH₃·）and Mn-OH.After that,it quickly happened rebound reaction and was oxidized to CH₃OH to finish the reaction.The influence of OEEFs on this reaction was studied.By constructing two electric fields,one is biased to the reaction axis direction,the other is perpendicular to the direction of the ring.It was found that the stability of transition states and reactants would change with the direction and field intensity in OEEFs.Activation energy is also influenced by OEEFs,Under the condition of OEEFs<0,activation energy reduces significantly.The perpendicular electric field to the direction of the ring has much stronger catalytic effect than biased axis direction.In this paper,it is shown that both Mn-O-O oxidation and following Mn（V）-oxo were carried out in the reaction of catalytic oxidation of methane to methanol.The addition of OEEFs can regulate the reaction,which is a kind of green catalyst with excellent research value.