ZSM-5 and ferrierite synthesized by magadiite conversion method in 1, 6-hexamethylenediamine system

• The binary crystallization phase diagram reveals the regular phase transformations.
• Highly crystallized and pure ZSM-5 and ferrierite could be obtained.
• The HMD is used as a structure directing agent in the conversion process.
• The as-synthesized ZSM-5 and ferrierite exhibit well thermal stability.
• The as-made ZSM-5 and ferrierite are exceptional stability towards strong acid.

ZSM-5 and ferrierite have been successfully synthesized by magadiite conversion method using 1, 6-hexamethylenediamine (HMD) as structure directing agent. The binary crystallization phase diagram was obtained by various reactant ratios of H2O/SiO2 and SiO2/Al2O3 and the regular phase transformations were also demonstrated. The optimized reactant HMD/SiO2 ratio was 0.6. The high crystalline ZSM-5 was composed of coffin-shaped crystallite with length of 4 μm where as ferrierite exhibited plate-like crystallite having a diameter of 8 μm. The 13C MAS NMR spectra revealed that the HMD which can be used as a structure directing agent in the conversion process was held tenaciously inside the pores of ZSM-5 and ferrierite. The formula of as-obtained ZSM-5 and ferrierite could be |K2.1(C6H16N2)4.2(H2O)16.9H8.4|[Si85.5Al10.5O192] and |K2.1(C6H16N2)0.9(H2O)6.4H2.2|[Si31.7Al4.3O72] respectively based on the compositional analysis. More over the structure of prepared ZSM-5 and ferrierite were collapsed when the temperature rose up to 1200 °C and 1100 °C respectively; both are exceptionally stable towards strong acid.

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