A COMPARATIVE-STUDY OF O-4(2-) ZRO2 AND ZEOLITE-BETA AS CATALYSTS FORTHE ISOMERIZATION OF N-BUTANE AND THE ALKYLATION OF ISOBUTANE WITH 2-BUTENE/

The activity, selectivity, and decay behavior of SO42-/ZrO2 (SZ) and z eolite Beta (Hbeta) catalysts are compared for two acid catalyzed dema nding reactions, i.e., the isomerization of n-butane, and the alkylati on of isobutane with 2-butene. The superacidity present in the SZ samp le makes this catalyst active for both reactions at lower temperatures than the zeolite. For the isomerization of n-butane the reaction path way leading to isobutane was seen to be different for both catalysts. A similar decay behavior was observed on the two catalysts, but the SZ sample gave a much higher selectivity to isobutane. For the alkylatio n reaction, the SZ catalyst is much more selective to TMP's than Hbeta at low reaction temperatures. The lower selectivity to TMP's obtained on Beta zeolite is mainly due to the formation of DMH's by dimerizati on of butenes, while undesirable cracking reactions leading to C5-C-7 products occur to a higher extent on the superacid SZ catalyst. The la tter deactivates much faster than the zeolite. The acid strength distr ibution, and hydrogen transfer activity were seen to determine the cha nges in product distribution with time-on-stream obtained on both cata lysts.