1-丁烯与H2S反应制备仲丁硫醇动力学研究

摘要

P2O5-MoO3/Al2O3 catalyst was prepared by the incipient-wetness impregnation method to catalyze the synthesis reaction of sec-butyl mercaptan from 1-butene and H2S. After eliminating the influence of internal and external diffusion,the intrinsic reaction kinetics of 1-butene and H2S on P2O5-MoO3/Al2O3 catalyst was studied. The effects of reaction temperature,1-butene partial pressure and H2S partial pressure on reaction rate were investigated under the conditions of 120-180 ℃ and 0.2 MPa. The catalytic mechanism of reaction of 1-butene and H2S on the P2O5-MoO3/Al2O3 catalyst was discussed. The intrinsic reaction mechanism of 1-butene and H2S on P2O5-MoO3/Al2O3 catalyst was dual site mechanism. 1-butene and H2S were co-adsorbed on the catalyst surface to react and form sec-butyl mercaptan and the surface reaction step was the rate-limiting step. According to the dual site mechanism the rate of reaction was derived: n AB 2AA BBA (1 )kppr Kp Kp0- ′ = + + n Pre-exponential factor k0=3.3×109,activation energy Ea=60.78 kJ/mol.%以Al2O3为载体，采用等体积浸渍法制备了P2O5-MoO3/Al2O3催化剂。在排除内外扩散影响的条件下，研究了1-丁烯与H2S在P2O5-MoO3/Al2O3催化剂上反应生成仲丁硫醇反应的本征动力学。在反应温度120～180℃、压力0.2 MPa的条件下，考察了反应温度、1-丁烯分压和硫化氢分压对反应速率的影响。对1-丁烯在P2O5-MoO3/Al2O3催化剂上的催化硫化机理进行了探讨。实验结果表明，1-丁烯与H2S在P2O5-MoO3/Al2O3催化剂上的反应机制是1-丁烯与H2S发生共吸附后由表面反应控制的二级催化反应，根据该机理得到反应动力学方程为n　　AB 2AA BBA (1)kppr Kp Kp0-′=++n　　根据实验数据得到其指前因子k0=3.3×109，活化能Ea=60.78 kJ/mol。