Next Article in Journal
First-Principles-Based Simulation of an Industrial Ethanol Dehydration Reactor
Previous Article in Journal
Propene Adsorption-Chemisorption Behaviors on H-SAPO-34 Zeolite Catalysts at Different Temperatures
Previous Article in Special Issue
A DFT Study of Acetylene Hydrogenation Catalyzed by S-Doped Pd1/g-C3N4
Open AccessArticle

Ag- and Cu-Promoted Mesoporous Ta-SiO2 Catalysts Prepared by Non-Hydrolytic Sol-Gel for the Conversion of Ethanol to Butadiene

1
Institue of Condensed Matter and Nanosciences—Université catholique de Louvain (UCLouvain), Place Louis Pasteur, 1, 1348 Louvain-la-Neuve, Belgium
2
Department of Chemistry, Masaryk University, Kotlarska 2, CZ-61137 Brno, Czech Republic
3
CEITEC MU, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
*
Author to whom correspondence should be addressed.
Catalysts 2019, 9(11), 920; https://doi.org/10.3390/catal9110920
Received: 28 September 2019 / Revised: 29 October 2019 / Accepted: 30 October 2019 / Published: 5 November 2019
(This article belongs to the Special Issue Active Sites in Heterogeneous Catalysis)
The direct catalytic conversion of bioethanol to butadiene, also known as the Lebedev process, is one of the most promising solution to replace the petro-based production of this important bulk chemical. Considering the intricate reaction mechanism—where a combination of acid-catalyzed dehydration reactions and metal-catalyzed dehydrogenation have to take place simultaneously—tailor-made bifunctional catalysts are required. We propose to use non-hydrolytic sol-gel (NHSG) chemistry to prepare mesoporous Ta-SiO2 materials which are further promoted by Ag via impregnation. An acetamide elimination route is presented, starting from silicon tetraacetate and pentakis(dimethylamido)tantalum(V), in the presence of a Pluronic surfactant. The catalysts display advantageous texture, with specific surface area in the 600–1000 m² g−1 range, large pore volume (0.6–1.0 mL g−1), an average pore diameter of 4 nm and only a small contribution from micropores. Using an array of characterization techniques, we show that NHSG allows achieving a high degree of dispersion of tantalum, mainly incorporated as single sites in the silica matrix. The presence of these monomeric TaOx active sites is responsible for the much higher dehydration ability, as compared to the corresponding catalyst prepared by impregnation of Ta onto a pristine silica support. We attempt to optimize the butadiene yield by changing the relative proportion of Ta and Ag and by tuning the space velocity. We also demonstrate that Ag or Cu can be introduced directly in one step, during the NHSG process. Copper doping is shown to be much more efficient than silver doping to guide the reaction towards the production of butadiene. View Full-Text
Keywords: Mesoporous metallosilicate; tantalum oxide; bioethanol; bifunctional catalysts; dehydration; dehydrogenation Mesoporous metallosilicate; tantalum oxide; bioethanol; bifunctional catalysts; dehydration; dehydrogenation
Show Figures

Figure 1

MDPI and ACS Style

Dochain, D.D.; Stýskalík, A.; Debecker, D.P. Ag- and Cu-Promoted Mesoporous Ta-SiO2 Catalysts Prepared by Non-Hydrolytic Sol-Gel for the Conversion of Ethanol to Butadiene. Catalysts 2019, 9, 920.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop