Quantum Chemistry Study On The Reaction Mechanism Of SO₂ And O₂ In The Catalyze Reaction.

Sulfuric acid industry is an important chemical engineering industry. With the V₂O₅ Catalyst, SO₂ can be catalyzed to produce SO₃. In this paper, we studied on the cluster models of V₂O₅ stable geometries and properties by means of Density Functional Theory (DFT) methods of quantum chemistry, and discussed the reaction mechanism of SO₂ and O₂ . Important information of potential energy surfaces such as structures and intermediate isomers and transition states possible reaction channels, reaction mechanisms and major products were obtained from the theoretical investigations. Some conclusions that were made in the present thesis may be helpful for further theoretical and experimental studies of this kind of reactions. The whole paper consists of five chapters, the main results are summarized as follows:The article introduces some basic principles of quantum: Schrodinger equation and three approximately(the non- theory of relativity approximately; the Born-Oppenheimer approximately; the single electronics approximately)and the Hartree-Fock-Roothaan equation .some calculation methods:(1) Half experience method, such as the AM1, the MINDO/3 and PM3.(2) ab initio method.(3)The DFT method.(4)The MΦller Plesset method.Using Density Functional Theory (DFT) methods , The optimization configurations and frequency analysis of the possible structures of cluster models of V₂O₅ were calculated by using DFT method with LANL2DZ basis set, and gain eight stable structures. Accordingly, we studied on the reaction mechanism of SO₂ and O₂ in the catalyze reaction.The optimization configurations and frequency analysis of the possible structures of SO₂,O₂,SO₃ were calculated by using DFT/B3LYP method with 6-311++G(3df,2p) basis set, the stable models were analyzed with NBO method ,and the relationship between forms and characteristics of them were also discussed.The reaction mechanism of SO₂ and O₂ has been studied by using quantum chemistry calculation methods. The geometries for all the stationary points on the potential energy surfaces were optimized fully, respectively, at the B3LYP/6-311++G(3df,2p) levels, intermediates and transition states were obtained. All the transition states were verified by the IRC calculation and frequency analysis, and single-point energies of all the species were calculated at the QCISD/6-31 lG(2df,p) level. The mechanism of reaction was confirmed and it showed reaction channels, the channel (1 )are the main reaction channels, the energy barrier is 143.56 kJ·mol^-1.