Synthesis and Growth Kinetics of Zeolite SSZ-39

SSZ-39, the aluminosilicate anologue of the AEI (AlPO4-18) topology, can be prepared in a straightforward manner using faujasite as an aluminum source.¹ This material shows great promise as a catalyst for deNOx catalysis, and thus a practical, simple, and scalable synthesis is something that would be highly desirable.² A variety of organic SDAs have been shown to afford SSZ-39 at various levels of efficacy, including N,N-dimethyl-3,5-dimethylpiperidinium, the organic SDA employed here. Prior work has shown that not only does this SDA lead to SSZ-39 formation, but has suggested that the isomer identity has a significant effect on growth kinetics.

The work presented here quantifies how the isomer identity impacts crystallization kinetics and how the composition of the parent faujasite used as the aluminum source impacts the synthesis kinetics and yield, and how wide of a gel composition space can be used to make phase pure SSZ-39. Specifically, the presence of the trans isomer is beneficial to the growth kinetics, leading to enhancements in the growth rate in some cases over 40%. The formation of SSZ-39 is also very sensitive to the composition of the faujasite used as an aluminum source as gels with identical compositions but different faujasites do not lead to SSZ-39 formation. Once SSZ-39 begins to form its growth rate appears to be approximately equal to the rate of faujasite dissolution. Finally, the Si/Al ratio of the material is confirmed appears to be influenced by the cis/trans ratio of the SDA. These results provide new insights into the formation of this industrially relevant catalyst that we hope the catalysis community will find useful.

Keywords: SSZ-39, zeolite, growth kinetics

References

1. Maruo, T., Yamanaka, N., Tsunoki, N., Sadakane, M., Sano, T. . ChemLett 43 (2014)

2. Moliner, M., Franch, C., Palomares, E., Grill, M., Corma, A. ChemComm 48 (2012).