2-苯基环己硫醇在γ-Al2O3和SiO2负载的WS2催化剂上的脱硫反应

合成了2-苯基环己硫醇(2-PCHT);通过等体积浸渍法制备了分别以γ-Al₂O₃和SiO₂作载体的WS₂催化剂，采用X射线衍射(XRD)、N₂物理吸附和透射电镜(TEM)技术对催化剂进行表征。在临氢和非临氢(Ar)条件下研究了2-PCHT在WS₂/ Al₂O₃和WS₂/SiO₂催化剂上的脱硫反应。结果表明：在240 ℃和5.0 MPa H₂条件下，2-PCHT在WS₂催化剂上主要通过β消除、氢解和脱氢3条平行路径脱硫，其中β消除和氢解并重，β消除反应速率快于氢解；非临氢条件下，主要通过β消除、C-S键均裂(或氢解)及脱氢3条平行路径脱硫，并以β消除为主；哌啶对β消除路径的抑制作用最大、对脱氢路径作用次之，但对氢解几乎没有影响，并促进了C-S键均裂；WS₂/ Al₂O₃的反应活性优于WS₂/SiO₂，可能与其活性组分的分散度较高有关；临氢条件下，2-PCHT的反应动力学可以用假一级模型描述；但其在非临氢条件下则不能用简单的幂函数拟合，可能归因于环烷基C-S键断裂机制的复杂性。

Desulfurization of 2-Phenylcyclohexanethiol OverWS2 Catalysts Supported on γ-Al2O3 and SiO2

2-Phenylcyclohexanethiol (2-PCHT) was synthesized. WS₂/Al₂O₃ and WS₂/SiO₂ were prepared by the incipient wetness impregnation, and characterized by X-ray diffraction (XRD), N₂ physical adsorption and transmission electron microscope (TEM). The desulfurizations of 2-PCHT over WS₂ catalysts supported on γ-Al₂O₃ and SiO₂ were investigated in the presence or absence of H₂. At 240 ℃ and under 5.0 MPa H₂, 2-PCHT undergoes desulfurization over the supported WS₂ catalysts via three parallel pathways: β elimination, hydrogenolysis and dehydrogenation. β elimination and hydrogenolysis are the two major pathways, and the reaction velocity in β elimination pathway is much faster than that in the hydrogenolysis pathway. Under Ar atmosphere, the parallel pathways are β elimination, homolytic C-S bond cleavage or hydrogenolysis, and dehydrogenation, withβ elimination serving as the dominate pathway. Piperidine strongly inhibits the β elimination pathway and the dehydrogenation pathway. It does not affect the hydrogenolysis pathway, and facilitates the homolytic C-S bond cleavage pathway. WS₂/Al₂O₃ is superior to WS₂/SiO₂ in the desulfurization of 2-PCHT, which is due to the higher dispersion of active phase. The kinetics of the desulfurization of 2-PCHT under H₂ is reasonably fitted by a pseudo-first-order model, whereas that under Ar cannot be described by the power-law rate expression, suggesting that the desulfurization of 2-PCHT is complex.