505
(10-membered ring), and large (12-membered ring) pore systems [8]. Some extralarge pore topology, with more than 12-membered ring (14–18) pore openings, also
exists [8]. Among the small-pore SAPO molecular sieves, SAPO-34, possessing
chabazite (CHA) topology is most widely explored in methanol-to-olefin (MTO)
reaction [9, 10]. It has mild acidic strength, with three-dimensional 8-ring channels
having a pore diameter of 0.38 nm and ellipsoidal cages of 0.67 nm × 1 nm [10].
Such kind of CHA topology generally arises at high crystallization temperatures.
Small Pore
Temperature : 200 °C
Temperature : 160 - 200 °C
Duration : 24 - 48 h
Duration : 20 - 48 h
Temperature : 150 - 200 °C
Duration : 24 - 144 h
Temperature : 130 - 150 °C
Duration : 4 - 215 h
Extra Large Pore
Large Pore
Medium Pore
Precursors of
Si + Al + P
SDA: DPA, DIPA,
SDA: TEAOH, DPA,
Isopropylamine Morpholie,
TEA, DEA, Piperidine
SDA: DPA, TEA, Cyclohexylamine,
N,N dimethylbenzylamine
SDA: DPA, TEOA, TBAOH,
TIPOA, Cyclohexylamine
Fig. 1 Synthesis conditions of various framework silicoaluminophosphate molecular sieves
Recent Developments on Clean Fuels over SAPO-Type Catalysts