Investigation of crucial synthesis parameters of rich Al-MTT framework zeolite: Toward more determination for synthesis zone of SSZ-32

• A precise synthesis zone of SSZ-32 (Al rich MTT) has been reported.
• Disc-shaped ZSM-5 crystals achieved as co-crystalline phase in high speed rotation.
• The smallest SSZ-32 crystals observed are in the range of 200 nm.
• The maximum Si/Al ratio to produce pure crystalline phase of SSZ-32 was 27.
• Quartz phase was crystallined at Si/Al ratio higher than 27.

Synthesis of zeolite materials using small neutral amines has received more attention recently because of the possibility to produce small crystals and lower price as compared other types of organic structured-directing agents (OSDA). For the first time, a precise synthesis zone of SSZ-32 is reported without seeds. Isobutylamine was applied as an OSDA to synthesize SSZ-32 zeolite (MTT framework). The main synthesis parameters such as rotation speed, synthesis time and Si/Al ratio were carefully investigated. The synthesis process was very sensitive to these studied parameters. The SSZ-32 crystals cannot be synthesized in less than 6 days with rotation speed of 35 rpm in a dynamic crystallization. The Si/Al ratio window was narrow as a ratio higher than 27 yielded to form an amorphous powder and quartz crystals. The smallest crystal size produced using isobutylamine was approximately 200 nm, which will be helpful in the elimination of diffusion limitation in the one-dimensional zeolite.

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