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Some catalytic properties of ZSM-5, a new shape-selective zeolite

Journal Article · · J. Catal.; (United States)

The new ZSM-5 zeolite has pore openings which sorb, at room temperature, straight-chain monomethyl-substituted paraffins and monocyclic hydrocarbons and excludes molecules larger than 1,3,5-trimethylbenzene. In the conversion of an equi-weight mixture of n-hexane, 3-methylpentane, and 2,3-dimethylbutane on amorphous silica-alumina, 2,3-dimethylbutane was four times more reactive than n-hexane and twice as reactive as 3-methylpentane; with ZSM-5, n-hexane was converted 8.8 times faster than 3-methylpentane at 375/sup 0/ and at the same rate at 510/sup 0/C, but further temperature increases did not change the conversion ratio to the intrinsic 0.5:1, as apparently the bulkier 3-methylpentane has a lower packing density inside the zeolite. Conversions of a mixture of 19 C/sub 5/-C/sub 7/ hydrocarbons at 35 atm and 315/sup 0/-340/sup 0/C showed the rates of disappearance, by chain length, as: n-C/sub 7/ > n-C/sub 6/ > n-C/sub 5/, and by isomers, as: nC/sub 7/ > 2-methyl-C/sub 6/ > 3-methyl-C-C/sub 6/ > dimethyl-C/sub 5/ > ethyl-C/sub 5/ > n-C/sub 6/ > 2-methyl-C/sub 5/ > 3-methyl-C/sub 5/ > dimethyl-C/sub 4/. The ratio of toluene-to-benzene alkylation rate constants at 315/sup 0/ and 340/sup 0/C and 35 atm was 0.7:1, compared with 1.4:1 on nonshape-selective catalysts. Graphs, tables, and 15 references.

Research Organization:
Mobil Res. Dev. Corp.
OSTI ID:
5714182
Journal Information:
J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 52:3; ISSN JCTLA
Country of Publication:
United States
Language:
English