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One‐Pot Synthesis of Zeolitic Strong Solid Bases: A Family of Alkaline‐Earth Metal‐Containing Silicalite‐1
Author(s) -
Zhou Yu,
Jin Yanhua,
Wang Meng,
Zhang Wei,
Xie Jingyan,
Gu Jing,
Wen Haimeng,
Wang Jun,
Peng Luming
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501894
Subject(s) - knoevenagel condensation , chemistry , alkaline earth metal , catalysis , inorganic chemistry , magic angle spinning , nmr spectra database , sorption , adsorption , metal , hydrolysis , selectivity , organic chemistry , nuclear magnetic resonance spectroscopy , spectral line , physics , astronomy
Fabricating stable strong basic sites in well‐preserved crystallized zeolitic frameworks still remains a difficult issue. Here, we reported a family of MFI‐type metallosilicate zeolites, AeS‐1 (Ae: alkaline‐earth metal ions of Mg, Ca, Sr or Ba; S‐1: silicalite‐1) through a direct one‐pot hydrothermal method involving the acidic co‐hydrolysis/condensation of the silica precursor with the Ae salts. Step‐by‐step full characterizations were designed and conducted for in‐depth discussion of the Ae status in AeS‐1. Strong basicity ( H _≈22.5–26.5) was detected in AeS‐1. The basicity was further confirmed by CO 2 sorption measurements, 13 C NMR spectra of chloroform‐adsorbed samples, and 1 H→ 13 C and 1 H→ 29 Si cross‐polarization magic‐angle spinning NMR spectra of ethyl cyanoacetate‐adsorbed samples. The results of Knoevenagel condensations demonstrated the excellent solid base catalysis of AeS‐1, which showed high activity, reusability, and shape‐selectivity, all of which are explained by Ae‐derived zeolitic intracrystalline strong basic sites.