Organic-Free Synthesis of Zeolite Y with High Si/Al Ratios: Combined Strategy of In Situ Hydroxyl Radical Assistance and Post-Synthesis Treatment

Jianyu Wang; Pusheng Liu; Mercedes Boronat; Pau Ferri; Zhaoguo Xu; Peng Liu; Baojian Shen; Zhendong Wang; Jihong Yu

doi:10.1002/anie.202005715

Organic-Free Synthesis of Zeolite Y with High Si/Al Ratios: Combined Strategy of In Situ Hydroxyl Radical Assistance and Post-Synthesis Treatment

Angew Chem Int Ed Engl. 2020 Sep 21;59(39):17225-17228. doi: 10.1002/anie.202005715. Epub 2020 Aug 13.

Authors

Jianyu Wang¹, Pusheng Liu^{1

2}, Mercedes Boronat³, Pau Ferri³, Zhaoguo Xu¹, Peng Liu⁴, Baojian Shen⁴, Zhendong Wang⁵, Jihong Yu^{1

6}

Affiliations

¹ State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
² Lanzhou Petrochemical Research Center, PetroChina, Lanzhou, 730060, P. R. China.
³ Instituto de Tecnologia Quimica, Universitat Politecnica de Valencia, Consejo Superior de Investigaciones Cientificas, 46022, Valencia, Spain.
⁴ State Key Laboratory of Heavy Oil Processing, The Key Laboratory of Catalysis of CNPC, College of Chemical Engineering, China University of Petroleum, Beijing, 102249, P. R. China.
⁵ Sinopec Shanghai Research Institute of Petrochemical Technology, State Key Laboratory of Green Chemical Engineering and Industrial Catalysis, Shanghai, 201208, P. R. China.
⁶ International Center of Future Science, Jilin University, Changchun, 130012, P. R. China.

PMID: 32558159
DOI: 10.1002/anie.202005715

Abstract

Zeolite Y, with a high SiO₂ /Al₂ O₃ ratio (SAR), plays an important role in fluidized catalytic cracking processes. However, in situ synthesis of zeolite Y with high SARs remains a challenge because of kinetic limitations. Here, zeolite Y with an SAR of 6.35 is synthesized by a hydroxyl radical assisted route. Density-functional theory (DFT) calculations suggest that hydroxyl radicals preferentially enhanced the formation of Si-O-Si bonds, thus leading to an increased SAR. To further increase the SAR, a dealumination process was carried out using citric acid, with a subsequent second-step hydrothermal crystallization, giving an SAR of up to 7.5 while maintaining good crystallinity and high product yield. The resultant zeolite Y shows good performance in cumene cracking. Introduced here is a new strategy for synthesizing high SAR zeolite Y, which is widely used in commercial applications.

Keywords: cracking; density-functional calculations; heterogeneous catalysis; radicals; zeolites.

Abstract

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