The Desulfurization Of 2-phenylcyclohexanethiol Over Sulfide Catalysts

In this dissertation,Ni-Mo-S,Co-Mo-S and Ni-W-S catalysts supported by different carriers?commercial alumina c-Al₂O₃,alumina Al₂O₃,silicon dioxide SiO₂?were synthesized by the equal volume stepwise impregnation method.An organic sulfur-containing compound2-phenylcyclohexanethiol?2-PCHT?was synthesized.Using 2-PCHT as the reactant,the C-S bond cleavage mechanism on the transition metal sulfide catalysts was explored to understand the cleavage mode of the alkyl C-S bond in the hydrogenated intermediates of aromatic heterocyclic sulfur compounds.Piperidine was added to the reactants to investigate the effect of nitrogenous compounds on the catalytic performance.The conversion of 2-PCHT under argon atmosphere is relatively high,indicating that the alkyl C-S bond is easy to break under non-hydrogen conditions.2-PCHT has two reaction paths under non-hydrogen conditions.The first path is?-elimination,which is the main path,and the second path is ring-closing reaction.The products of 2-PCHT include:?-elimination products phenylcyclohexenes?PCHEs?;ring-closing products tetrahydro-dibenzothiophene?THDBT?and hexahydro-dibenzothiophene?HHDBT?;1-PCHE dehydrogenation and hydrogenation products biphenyl?BP?and cyclohexyl benzene?CHB?;1-PCHE isomerization product cyclopenten-ylmethyl-benzene?CPEMB?.Piperidine has an inhibitory effect on the?-elimination and the ring-closing pathway of the 2-PCHT desulfurization reaction.Comparing the three types of catalysts,it can be found that the desulfurization ability and dehydrogenation ability of the Ni-W-S catalyst are weaker than the Ni-Mo-S and Co-Mo-S catalysts.Comparing with Co-Mo-S and Ni-Mo-S,the catalytic effect of Co-Mo-S on c-Al₂O₃and Al₂O₃ is better.On the SiO₂ carrier,the catalytic effect of Ni-Mo-S is better.The dehydrogenation activity of the catalyst supported on the SiO₂ carrier is better than that of the Al₂O₃ carrier.