Synthesis of ATN‐Type FeAPO‐39 Molecular Sieves without Solvent using the Additional Structure‐Directing Effect of the Iron Source.

ATN‐type FeAPO‐39 molecular sieves with high iron content has been successfully synthesized under non‐solvent conditions, which is the first example of iron‐incorporated aluminophosphate with the ATN‐zeotype structure. The optimum synthetic conditions of this material were refined. It was found that the following synthetic conditions, i.e. a low P2O5/Al2O3 ratio, a high DPA/Al2O3 ratio (DPA: di‐n‐propylamine) and an elevated crystallization temperature, seemed to be more favorable for the non‐solvent synthesis of ATN phase. The composition and structural characteristics of resultant relatively pure FeAPO‐39 molecular sieves were intensively studied by XRD, FT‐IR, TG‐DTA, CHN elemental analysis, ICP‐AES, SEM, TEM, N2 physisorption, UV/Vis diffuse reflectance spectroscopy and Mössbauer spectroscopy analyses. The iron content and zeolite yield of FeAPO‐39 material were found to be as high as 5.56 wt.‐% and 82.6 %, respectively. The results of FT‐IR, TG‐DTA and CHN elemental analysis indicate that DPA molecules may co‐direct the synthesis of ATN zeolites along with additional structure‐directing agent NH4+ ions resulting from iron source. Owing to the specific structure‐directing role provided by iron source, the synthetic strategy presented here may find a potential application in the non‐solvent synthesis of other aluminosilicate and aluminophosphate zeolites with novel frameworks. The incorporation of iron into the framework of ATN‐zeotype structure was achieved in non‐solvent system. DPA molecules and additional NH4+ ions resulting from iron compound act as the SDA. [ABSTRACT FROM AUTHOR]