from first principles PP-I-1

PP-III-114Peculiarities of Ethane Aromatization over Bifunctional Metal-ContainingCatalystVosmerikova L.N. 1 , Zaikovskii V.I. 2 , Vosmerikov A.V. 11 Institute of Petroleum Chemistry SB RAS, Tomsk, Russia2 Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russialkplu@ipc.tsc.ruModern oil refining and petrochemistry heavily rely on the use catalysts, based on syntheticzeolites. In order to develop general approaches to controlling and predicting their catalyticactivity one has to know the mechanisms taking into account the state of every component inthe catalyst system. The purpose of this study is to propose a staged scheme of ethanearomatization based on a detailed analysis of Pt and Ga states, their localization inPt-galloalumosilicates, and the composition of ethane conversion products over this catalystfor different conversion rates.According to the HRTEM data due to the introduction of more than 0.1% of platinum intoGa-AS, the gallium migrates to the outer surface of the zeolite particles, while platinum formsclusters in its channels. In addition, the decrease in the gallium content in the inner space ofthe carrier channels with increasing platinum content was registered by the EDX-analysis.This suggests the degradation of adsorbed Ga-Pt complexes resulting in the Ga displacementfrom the channels to the outer surface of zeolite crystals whereas Pt clusters remains insidethe channels. The reduction of gallium ions results in the formation of amorphous sphericalparticles of metallic Ga on the surface of support.Catalytic studies show that the introduction of platinum into galloalumosilicate leads to theacceleration of ethane dehydrogenation as a key stage in the process of conversion of ethane.The hydride-ion separates from the molecule of ethane to form ethylene with participation ofPt-Ga clusters. The galloalumosilicate supplemented with 0.3% Pt exhibits the highestactivity and selectivity towards the formation of aromatic hydrocarbons from ethane, which isto be due to the increased concentration of platinum in its dispersed state and to the optimizedcomposition and ratio between the catalytic centers of various origins.Thus, a combination of such active metal components as gallium and platinum, on the onehand and interaction of acid sites of the zeolite support on the other ensure high aromatizationefficiency of the catalyst during ethane conversion.274