An oxygenate conversion catalyst useful in the conversion of oxygenates
such as methanol to olefinic products may be improved by the use of a
catalyst combination based on a molecular sieve in combination with a
co-catalyst comprising a mixed metal oxide composition which has
oxidation/reduction functionality under the conditions of the conversion.
This metal oxide co-catalyst component will comprise a mixed oxide of one
or more, preferably at least two, transition metals, usually of Series 4,
5 or 6 of the Periodic Table, with the metals of Series 4 being
preferred, as an essential component of the mixed oxide composition. The
preferred transition metals are those of Groups 5, especially titanium
and vanadium, Group 6, especially chromium or molybdenum, Group 7,
especially manganese and Group 8, especially cobalt or nickel. Other
metal oxides may also be present. The preferred molecular sieve
components in these catalysts are the high silica zeolites and the SAPOs,
especially the small pore SAPOs (8-membered rings), such as SAPO-34.
These catalyst combinations exhibit reduced coke selectivity have the
potential of achieving extended catalyst life. In addition, these
catalysts have the capability of selectively converting the hydrogen
produced during the conversion to liquid products, mainly water, reducing
the demand on reactor volume and product handling.