Identification of tert-Butyl Cations in Zeolite H-ZSM-5: Evidence from NMR Spectroscopy and DFT Calculations

Weili Dai; Chuanming Wang; Xianfeng Yi; Anmin Zheng; Landong Li; Guangjun Wu; Naijia Guan; Zaiku Xie; Michael Dyballa; Michael Hunger

doi:10.1002/anie.201502748

Identification of tert-Butyl Cations in Zeolite H-ZSM-5: Evidence from NMR Spectroscopy and DFT Calculations

Angew Chem Int Ed Engl. 2015 Jul 20;54(30):8783-6. doi: 10.1002/anie.201502748. Epub 2015 Jun 11.

Authors

Weili Dai¹, Chuanming Wang², Xianfeng Yi³, Anmin Zheng³, Landong Li^{4

5}, Guangjun Wu¹, Naijia Guan^{1

6}, Zaiku Xie⁷, Michael Dyballa⁸, Michael Hunger⁹

Affiliations

¹ Key Laboratory of Advanced Energy Materials Chemistry of the Ministry of Education, Nankai University (P.R. China).
² SINOPEC, Shanghai Research Institute of Petrochemical Technology, Shanghai 201208 (P.R. China).
³ State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (P.R. China).
⁴ Key Laboratory of Advanced Energy Materials Chemistry of the Ministry of Education, Nankai University (P.R. China). lild@nankai.edu.cn.
⁵ Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071 (P.R. China). lild@nankai.edu.cn.
⁶ Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071 (P.R. China).
⁷ SINOPEC, Shanghai Research Institute of Petrochemical Technology, Shanghai 201208 (P.R. China). xzk@sinopec.com.
⁸ Institute of Chemical Technology, University of Stuttgart, Stuttgart 70550 (Germany).
⁹ Institute of Chemical Technology, University of Stuttgart, Stuttgart 70550 (Germany). michael.hunger@itc.uni-stuttgart.de.

PMID: 26096840
DOI: 10.1002/anie.201502748

Abstract

Experimental evidence for the presence of tert-butyl cations, which are important intermediates in acid-catalyzed heterogeneous reactions, on solid acids has still not been provided to date. By combining density functional theory (DFT) calculations with (1)H/(13)C magic-angle-spinning NMR spectroscopy, the tert-butyl cation was successfully identified on zeolite H-ZSM-5 upon conversion of isobutene by capturing this intermediate with ammonia.

Keywords: NMR spectroscopy; adsorption; density functional calculations; heterogeneous catalysis; zeolites.