二甲基二硫醚对Ni/Al_2O_3催化剂加氢性能的影响

Study of poisoning effect of dimethyl disulfide on Ni /Al_2O_3 catalyst for hydrogenation

考察了二甲基二硫醚(CH3SSCH3)对Ni/Al2O3催化剂上苯、环己烯和苯乙烯加氢活性的影响,并采用BET、XRD、H2-TPR、XPS、SEM和EA等手段对催化剂进行表征。实验结果表明,在CH3SSCH3存在下,Ni/Al2O3催化剂对苯和环己烯加氢迅速失活,且环己烯加氢对CH3SSCH3的耐硫性要略强于苯加氢,而苯乙烯中共轭烯烃的加氢转化率则维持100%长时间不变。CH3SSCH3的影响顺序为芳环>单烯烃>共轭烯烃。此外,通过设计实验研究了CH3SSCH3对催化剂的毒化机理,发现CH3SSCH3分子首先吸附在催化剂的表面,并发生氢解生成甲烷随尾气逸出,故CH3SSCH3分子中碳对催化剂的失活影响较小,而留下的硫原子则与镍活性组分发生相互作用,毒化催化剂。

Poisoning effect of dimethyl disulfide （CH3SSCH3 ） on NifA1203 catalysts for hydrogenation of benzene, cyclohexene and styrene was studied. The structures and properties of the catalysts were investigated by means of BET, XRD, H2-TPR, XPS, SEM and EA. Results indicated that with the existence of CH3 SSCH3, Ni/Al2O3 catalysts quickly deactivated for benzene and cyclohexene hydrogenation, while the activity for styrene hydrogenation remained well. The sulfur tolerance of Ni/A1203 catalysts for cyclobexene hydrogenation was little better than that of benzene hydrogenation. The conversion of conjugated double bond of styrene can keep 100% for a long time. For hydrogenation reactions, the poisoning effects of CH3SSCH3 over NifA1203 were in the order of aromatic nucleus〉monoene〉conjugated alkene. In addition, poisoning mechanism of CH3 SSCH3 for Ni/Al2O3 catalyst was also discussed. CH3SSCH3 molecules were firstly adsorbed on the surface of catalyst and then dissociated to CH4 under the function of hydrogen and catalyst. It is concluded that the toxicity of carbon in CHaSSCH3 for catalysts is neglectful and remaining sulfur is the dominant poisoning factor by the interaction with active component.