Facile and Rapid Synthesis of Durable SSZ-13 Catalyst Using Choline Chloride Template for Methanol-to-Olefins Reaction

Xiongchao Lin,Sasha Yang,Xiaojia Li,Yonggang Wang,Caihong Wang

doi:10.3390/catal11101250

Xiongchao Lin, Sasha Yang + Show 3 more

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https://doi.org/10.3390/catal11101250

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Abstract

In the current study, a facile and rapid synthesis approach for a SSZ-13 catalyst using choline chloride (CC) as a template was proposed, and the catalytic performance for the methanol-to-olefins (MTO) reaction was examined. With a proper amount of CC addition (i.e., m(CC)/m(SiO2) = 0.14), uniform and homogeneously distributed cubic SSZ-13 crystals were obtained within 4 h with lower aggregation. The synthesized catalyst demonstrated excellent porous features with a total specific surface area and mesopore volume of 641.71 m2·g−1 and 0.04 cm3·g−1, respectively. The optimized strong and weak acid sites on SSZ-13 were obtained by regulating the m(CC)/m(SiO2) ratio. The less strong acid sites and a larger amount of weak acid sites in the synthesized catalyst were conducive to the catalytic performance of the MTO reaction under a lower reaction temperature (450 °C). The appropriate acidity and well-developed pore structure of synthesized SSZ-13 could also slow down the carbon deposition rate and, thus, significantly improve the catalytic lifetime of the catalyst. The methanol conversion rate and initial selectivity of light olefin using the synthesized catalyst could maintain over 95% and 50%, respectively, and a lifetime of 172 min was achieved. Although the low olefin selectivity of the synthesized SSZ-13 catalyst was slightly lower than that of the purchased one, its desirable features were thought to have good potential for industrial application.

Highlights

IntroductionThe methanol-to-olefins (MTO) reaction has been intensively studied in recent years with a particular focus on the development of highly reactive and durable catalysts [1,2,3]
This study aimed to demonstrate a novel synthesis process for the SSZ-13 zeolite based on the traditional hydrothermal method
The time consumption, high cost, and polluting synthesis process are the key drawThe time consumption, high cost, and polluting synthesis process are the key drawbacks for the industrial utilization of SSZ-13 catalysts in MTO technology

Summary

Introduction

The methanol-to-olefins (MTO) reaction has been intensively studied in recent years with a particular focus on the development of highly reactive and durable catalysts [1,2,3]. Chabazite (CHA) zeolite with a favorable structure is expected to be an ideal candidate for the MTO reaction [4,5]. The ordered crystal structure is quite essential for the preparation of the SSZ-13 zeolite. The costly N, N, N-trimethyl-1-adamantyl ammonium hydroxide (TMADaOH) was used as a template for the synthesis of SSZ-13. The properties of the hierarchical pore SSZ-13 are excellent, its synthesis process is complicated with the inevitable environmental pollution caused by the toxic template precursor TMADaOH. A novel route for rapid and facile synthesis of the SSZ-13 catalyst is crucial and necessary

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Conclusion