Hydrocarbon sorption properties of pure silica MCM-22 type zeolite

The adsorption properties of the MWW compositional end member, ITQ-1, have been explored empirically and via computer simulation using n-hexane, 3-met hylpentane, 2,3-dimethylbutane, p-xylene and ethylbenzene as adsorbate prob es. n-Hexane and 3-methlypentane diffuse rapidly and both have a sorption l imit of four molecules per unit cell, three of which are in the large chann el cavities. 2,3-dimethylbutane sorbs more slowly through the 10-ring windo ws; the limiting three molecules per unit cell are all in the large cavitie s. The two aromatics adsorb in both channel systems, with p-xylene diffusin g rapidly and ethylbenzene more slowly but much faster than 2,3-dimethylbut ane. No clear distinction between intra- and extra-crystalline adsorption w as observed. Computer modeling indicated distinctions between the two chann el systems. (C) 2000 Elsevier Science B.V. All rights reserved.