摘要：为了研究固硫反应中CaS与SO₂的反应机理,采用密度泛函理论中的B3LYP方法,在6-311G++(d,p)水平上优化得到反应物、中间体、过渡态和产物的稳定构型和相应的能量值。结果表明:CaS与SO₂反应时,先络合生成具有链状的中间体IM₁,随后经过S原子与O原子成键,生成过渡态TS;TS经过分子重排和能量重新排布生成中间体IM₂、IM₃、IM₄,最后生成产物CaSO₄和硫单质;由中间体IM₄到产物P₁的过程能垒最大,说明该步骤是反应的速率控制步骤。

关键词：固硫反应；反应机理；密度泛函理论；量子化学

Abstract： To study the reaction mechanism between CaS and SO₂ in desulfurization reaction， stable molecular configurations of reactants， intermediates， transition state， and products were optimized at the 6-311G++ （d，p） level， using the B3LYP method in density functional theory， and the corresponding energy values of them were obtained. The results show that the reaction of SO₂ and CaS forms chain intermediate IM1 firstly， then transient state TS is generated by S and O atoms forming chemical bond. Intermediates IM_2,IM₃ and IM₄ are generated through molecular rearrangement and energy configuration of TS， product CaSO₄and sulfur are finally generated. The energy barrier of intermediate IM₄ to product P₁ is the greatest， which shows that it is the rate-determining step. 

Keywords: desulfurization reaction； reaction mechanism； density functional theory； quantum chemistry