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Ag‐Promoted ZrBEA Zeolites Obtained by Post‐Synthetic Modification for Conversion of Ethanol to Butadiene
Author(s) -
Sushkevich Vitaly L.,
Ivanova Irina I.
Publication year - 2016
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201600572
Subject(s) - silanol , catalysis , zeolite , fourier transform infrared spectroscopy , zirconium , 1,3 butadiene , nuclear chemistry , inorganic chemistry , chemistry , adsorption , hydrothermal synthesis , ethanol , materials science , hydrothermal circulation , organic chemistry , chemical engineering , engineering
Abstract 1,3‐Butadiene was synthesized from ethanol using zirconium‐containing zeolite beta (ZrBEA) catalysts doped with 1 wt % silver. The Zr was planted using post‐synthesis modification by dealumination of the parent zeolite followed by treatment with ZrOCl 2 in a DMSO solution. FTIR and NMR spectroscopy were used to investigate the planting process by preparing materials with different Si/Al ratios and crystal sizes. The results showed preferential grafting of Zr to the terminal silanols present on the external surface of the zeolite crystals instead of incorporation of Zr into silanol nests. The grafting yielded highly accessible Zr(OSi) 3 OH open sites with high Lewis acidity, as confirmed by FTIR spectroscopy of adsorbed CO. These sites are shown to be extremely active for the conversion of ethanol to butadiene. Ag/ZrBEA catalysts prepared using the post‐synthesis method showed significant advantages compared with Ag/ZrBEA catalysts synthesized using a conventional hydrothermal procedure. The best catalyst performance in terms of butadiene formation rate (3 μmol g −1 s −1 ) was observed over Ag/Zr(3.5)BEA(75) (containing 3.5 wt % Zr), which had the smallest crystal size and the highest content of Zr open sites of the prepared catalysts.