| 摘要 |
Compositions of matter, including: A mixture of at least one oxide of manganese and at least one oxide of a Lanthanum Series metal, preferably lanthanum or cerium, or at least one oxide of niobium. The above compositions are particularly useful as catalytic compositions for the conversion of C3 and C4 hydrocarbons to less saturated hydrocarbons, particularly ethylene and propylene and preferably ethylene. The life of the catalyst for the selective production of ethylene is extended by carrying out the reaction in the presence of steam. The steam substantially increases the active life of the catalytic composition, before regeneration is necessary, as well as significantly increasing the selectivity to ethylene. Limiting the amount of "bound" or "fixed" sulfur in the catalytic composition also improves the catalyst.
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