Synthesis of EU‐1/ZSM‐48 Co‐Crystalline Zeolites from High‐Silica EU‐1 Seeds: Tailoring Phase Proportions and Promoting Long Crystalline‐Phase Stability. Issue 25 (17th April 2018)

• Record Type: Journal Article
• Authors: Zhang, Yafei; Liu, Yasheng; Sun, Liyuan; Zhang, Luoming; Xu, Jun; Deng, Feng; Gong, Yanjun
• Is Part Of: Chemistry. Volume 24:Issue 25(2018)
• Page Start: 6595
• Page End: 6605
• Publication Date: 2018-04-17
• Subjects: catalytic cracking -- composite zeolites -- crystal growth -- synthetic methods -- zeolites; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201705805
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A facile, specific, seed‐assisted strategy for the synthesis of EU‐1/ZSM‐48 co‐crystalline zeolites in the presence of hexamethonium ions (HM 2+ ) has been developed. EU‐1/ZSM‐48 co‐crystalline zeolites with various phase proportions, with EU‐1 in the range of 25 wt %–86 wt %, were obtained by adding high‐silica EU‐1 seeds (SiO2 /Al2 O3 ratio of 300) and adjusting the synthesis parameters. Not only can the phase proportions of EU‐1/ZSM‐48 co‐crystalline zeolites be controlled, but also the stability period for co‐crystallization of the two phases can be extended through varying the amount of EU‐1 seeds and the HM 2+ template. Moreover, with the increase of the EU‐1 proportion in the EU‐1/ZSM‐48 co‐crystalline, the framework SiO2 /Al2 O3 ratios of EU‐1 phase promotes steadily. Major differences in acidity and textural properties of the EU‐1/ZSM‐48 co‐crystalline zeolites (Coz) were found with varying phase proportions, due to their distinct topological structures, crystal morphology and asymmetry between the EU‐1 and ZSM‐48 phases. For instance, the EU‐1/ZSM‐48 zeolite containing 75 wt % of EU‐1 (Coz‐75) possesses specific acidity and mesoporous characteristics, showing an excellent catalytic activity and stability in n ‐hexane cracking reaction. Compared to EU‐1, ZSM‐48, and a mechanical mix of the two zeolites (Mix‐75), Coz‐75 resulted in the highest hexane conversion and yields of light olefins, with a propylene yield, in particular, up to 38.3 wt %, which is 6.3 % more than that of the Mix‐75 sample. Abstract : Composites zeolites : A series of EU‐1/ZSM‐48 co‐crystalline zeolites with a long crystallization stability can be obtained with a high‐silica seeded method. This article discusses the influences of the different synthesized factors and the synthesis process. The EU‐1/ZSM‐48 co‐crystalline zeolite also displays great performance in the n ‐hexane catalytic cracking reaction.