CONTROLLING SELECTIVITY VIA MOLECULAR ASSEMBLING IN CONFINED SPACES: ALKANES-ALKENES-AROMATICS IN FAU ZEOLITES
Liquid phase adsorption of alkane/alkene/aromatic mixtures in FAU supercages is governed by a combination of enthalpic and entropic effects. Large energetic interactions between specific molecular moieties (e.g. double bond or aromatic ring) and adsorption sites, lead to a preferential adsorption of aromatics compared to alkenes and alkanes.Entropic packing effects on the other hand are shown to be able to clearly outweigh normal tendencies for selectivity based on adsorbate properties (e.g. ＃ C-atoms) and structural properties (e.g. aluminium contents) observed at low coverage. For the first time, it was shown that even in adsorbents or catalysts with relatively large pores, molecular selectivity is achieved at high degree of pore occupancy as a result of the assembly of molecules inside such pores. These selectivity effects, which are not acting at low degree of pore filling, depend in a subtle way on molecular size and shape,functional groups, pore size and geometry (e.g. spherical cage versus tubular pore),cation number and type, presence of solvents and so on. This concept of packing induced selectivity offers perspectives for new separation and catalytic processes.
J.F.DENAYER I.DAEMS G.V.BARON PH.LEFLAIVE A.METHIVIER
Department of Chemical Engineering, Vrije Universiteit Brussel Pleinlaan 2, B-1050 Brussel, Belgium Institut Fran(c)ais du Pétrole - Lyon, BP n°3, 69390 Vernaison, France
国际会议
天津
英文
138-153
2006-05-22（万方平台首次上网日期，不代表论文的发表时间）