Abstract: The molecular sieve SAPO-56 has been synthesized hydrothermally using N,N,N',N' tetramethyl 1,6-dihexane as template. In the Al₂O₃-SiO₂-P₂O₅ medium, phase diagram of SAPO-56 was obtained. Pure phase region of SAPO-56 appeared in the range of 0.5<n(SiO₂)/n(M)<0.7(M=SiO ²+Al₂O+³P₂O₅), 0.15<n(Al₂O₃)/n(M)<0.4 and 0.1<n(P₂O₅)/n(M)<0.3. The effect of template amount on the synthesis of SAPO-56 was also investigated. Provided that other compositions (Si, Al, Pand H₂O) was fixed, it presented pure SAPO-56 crystal in the ratios of n(TMHD)/n(P₂O₅)≥2. The properties of SAPO-56 were characterized by XRD, SEM, TG-DTA, IRand adsorption technique which suggested that SAPO-56 had a good thermal stability and large water adsorption capacity. In the methanol to olefins reaction, SAPO-56 catalyst exhibited a high activity and selectivities to C₂, C₃ olefins.

Key words: SAPO-56, Molecular sieve, Synthesis, Methanol conversion