Synthesis of nanosized SAPO-34 with the assistance of bifunctional amine and seeds.

Nanosized SAPO-34 with a tunable silica content (acidity) has been synthesized with the assistance of bifunctional amine 1-[2-(2-hydroxyethoxy)ethyl]piperazine (HEEP) or its analog 1-(2-hydroxyethyl)piperazine (HEP), in which the piperazinyl group acting as a co-template prompts the formation of the pure CHA phase, and the hydroxyl/ether groups help inhibit the crystal growth. The resultant nanocrystallines possess a large amount of Si(4Al) species, improve transport properties as confirmed by IGA, and thus exhibit enhanced MTO catalytic performance.