苯加氢烷基化制备环己基苯催化剂的研制及其应用

Investigation on Development and Application of Catalysts for Hydroalkylation of Benzene(BZ) to Cyclohexylbenzene(CHB)

摘要:

以β为载体采用等体积浸渍法制备环己基苯双功能复合催化剂。并用X射线粉末衍射(XRD)、氮气吸附脱附(BET)、程序升温脱附(TPD) 及高分辨透射电子显微镜（HR-TEM）对催化剂组分间的协同催化作用进行考察。在固定床反应装置上考察了催化剂稳定性以及对苯转化率和环己基苯选择性的影响。结果表明：在Ni/Hβ双功能催化剂中掺入不同金属助剂可调控催化剂表面的负载组分颗粒大小、活性分散度、B/L酸比例，以及金属催化加氢功能和酸催化烷基化功能的匹配。在4%(w)Ni-0.2%(w)Pd-3%La(w)/Hβ催化剂中，通过固定床反应，在220℃、H2 GHSV为2500 h-1、苯LHSV为2.0 h-1条件下，苯转化率达34.44%，环己基苯选择性为74.67%，催化剂性能在240 h内没有明显下降。

Abstract:

A series of composite bi-functional catalysts, used to hydroalkylation of BZ into CHB, were prepared by incipient wetting method on the carrier of β. The synergistic effects between catalyst components were investigated by using XRD, BET, TPD and HR - TEM characterization methods. The catalytic performance stability of different catalysts was compared in a fixed bed reactor. And the effect of catalyst composition on BZ conversion and CHB selectivity was examined. The results show that: adding different metals as co-catalysts into Ni/Hβ can regulate the loading particle size, active center dispersion, B/L acidic site concentration on the surface of the catalyst, and the matching of metal catalytic hydrogenation and acid catalytic alkylation of the bi-functional catalyst.The catalytic performance of hydrogenation and alkylation is matched well over 4%Ni-0.2%Pd-3%La/Hβ. Accordingly, the conversation of benzene and the selectivity of cyclohexylbenzene can reach 34.44% and 74.67%, respectively, under the conditions of 220℃, H2 GHSV of 2500 h-1 and benzene LHSV of 2.0 h-1 over the catalyst, and the catalytic performance has no obvious decline within 240 hours.