| 摘要 |
Compsns. useful as catalysts comprise: (a) a zeolite of type L; (b) a metal of Group VIII, pref. Pt; and (c) Ca, Sr or esp. Ba, pref. introduced into the zeolite by ion-exchange. Pref. the majority of the zeolite crystals are larger than 50 nm. A pref. compsn. (I) comprises zeolite L with 1-20 wt.% Ba and 0.1-1.5 wt.% Pt. Pref. at least 80% of the zeolite particles are larger than 100 nm. (I) can be used for reforming, e.g. of straight-run naphtha, in presence of H2: pref. conditions are 430-550 deg , a pressure of 3.5-21 atmospheres, a ratio of H2/hydrocarbon of 2:1 to 6:1, and LHSV 0.1-10. The catalyst is deactivated by S. which must be removed from the feestock, e.g. by hydrofining. The compsns. are useful for reforming, dehydrocyclisation (esp. of C6-C8 paraffins) to aromatics, dealkylation of toluene to benzene, and dehydroisomerisation of alkylcyclopentanes to aromatics. Prod. yields are high: e.g. selectivity of conversion of n-hexane to benzene can be 90%. Catalyst life is adequate, and greater than that of known zeolitic reforming catalysts. |
