Nickel amine complexes as structure directing agents for aluminophosphate molecular sieves; a new route to supported nickel catalysts
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Colleges, School and Institutes
Open framework aluminophosphates (AlPOs) with the framework types CHA, AFI, AEI, SAS and SAV have been prepared using nickel complexes of linear and macrocyclic polyamines as structure-directing agents: The [Ni(diethylenetriamine)(2)](2+) complex has been used to prepare aluminophosphate-fluoride versions of the CHA and AFI topologies as well as substituted metalloaluminophosphates (MAPOs) and silicoaluminophosphates (SAPOs) with the CHA topology; the nickel complex of the macrocycle 1,4,7,10-tetraazacyclododecane (cyclen) acts as a structure-directing agent for MAPO-18 (AEI topology), and the nickel complexes of 1,4,8,11-tetraazacyclotetradecane (cyclam) and 1,4,8,11-tetramethylcyclam direct the formation of STA-6 (SAS topology) or STA-7 (SAV topology) depending on the inorganic composition and the type of amine added as a cobase to control the synthesis pH. Magnesioaluminophosphate-5 (AFI topology) containing complexed nickel has been prepared using a novel mixed azamacrocycle-quinuclidinium cation as a structure-directing agent. Nickel complex-containing AlPOs and SAPOs with the CHA framework topology have been calcined and used as catalysts for the conversion of butane over the temperature range 375-575 degreesC with a WHSV of 1.8 h(-1). The inclusion of nickel increases the rate of conversion and also changes the composition of the products from the full C1-C4 range to pure methane. This behavior is attributed to the reduction of Ni(II) to finely dispersed supported nickel particles.
|Number of pages||1|
|Journal||Topics in Catalysis|
|Publication status||Published - 1 Jan 2003|
- nickel complexes, microporous aluminophosphates, supported nickel catalysts