Influence of the nitric acid treatment on Al removal, framework composition and acidity of BEA zeolite investigated by XRD, FTIR and NMR

Baran, Rafał; Millot, Yannick; Onfroy, Thomas; Krafft, Jean‐Marc; Dźwigaj, Stanisław

doi:10.1016/j.micromeso.2012.06.055

Cited by 110 publications

(82 citation statements)

References 40 publications

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“…The crystalline structure was preserved during the acid treatments, which is in agreement with the literature for HNO 3 -treated beta materials [83,[85][86][87][88][89]. The SSIE process did not lead to measurable changes in the crystalline structure of the materials deAl-betan.…”

Section: Characterisation Of the Modified Zeolite Beta Materialssupporting

confidence: 90%

One-pot conversion of furfural to useful bio-products in the presence of a Sn,Al-containing zeolite beta catalyst prepared via post-synthesis routes

Antunes

Lima

Neves

et al. 2015

Journal of Catalysis

137

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Aiming at the valorisation of furfural (Fur) via sustainable routes based on process intensification and heterogeneous catalysis, the one-pot conversion of this renewable platform chemical to useful bio-products, namely furfuryl alkyl ethers (FEs), levulinate esters (LEs), levulinic acid (LA), angelica lactones (AnLs) and -valerolactone (GVL), was investigated using a single heterogeneous catalyst, in 2-butanol, at 120 ºC. Various chemical 2 reactions are involved in this process, which requires catalysts with active sites for acid and reduction chemistry. For this purpose, it was explored for the first time the catalytic potentialities of modified versions of zeolite beta containing Al and Sn sites prepared from commercially available nanocrystaline zeolite beta via post-synthesis partial dealumination followed by solid-state ion-exchange. The post-synthesis conditions influenced considerably the catalytic performances of these types of materials. The best-performing catalyst was (Sn) SSIE -beta1 with Si/(Al+Sn)=19 (Sn/Al=27.6), which led to total yield of bio-products of 83% at 86% Fur conversion, and exhibited steady catalytic performance for six consecutive runs. A systematic catalytic study using the prepared catalysts with different bio-products as substrates, together with the molecular level and microstructural characterisation of the materials, helped understand the effects of different material properties on the specific reaction pathways in the overall system. These studies led to mechanistic insights into the reaction network of Fur to the bio-products in alcohol media, upon which a kinetic model was developed for the first time. The superior performance of (Sn) SSIE -beta1 in various steps was related to the dealumination degree, dispersion and amount of Sn-sites, and acid properties.

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Section: Characterisation Of the Modified Zeolite Beta Materialssupporting

confidence: 90%

One-pot conversion of furfural to useful bio-products in the presence of a Sn,Al-containing zeolite beta catalyst prepared via post-synthesis routes

Antunes

Lima

Neves

et al. 2015

Journal of Catalysis

137

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“…FT IR analysis was carried out to investigate the acidic character of the prepared catalysts [46][47][48][49]. In the hydroxyl region of the spectra, recorded after outgassing at 500°C (spectra not reported) several common features appear for samples 1 and 8 (calcined samples):…”

Section: -Ft Ir Investigation Of Zeolite Aciditymentioning

confidence: 99%

Ethylene production via catalytic dehydration of diluted bioethanol: A step towards an integrated biorefinery

Rossetti

Compagnoni

Finocchio

et al. 2017

Applied Catalysis B: Environmental

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After a preliminary thermodynamic investigation, proper operating conditions have been selected to maximise ethylene productivity by ethanol dehydration and limit side products such as coke and higher olefins or oxygenates. We focused on the possibility to operate with a diluted bioethanol solution (ca. 50 wt%), which represents a promising and convenient raw material, obtainable by simple flash concentration of the fermentation broth. Furthermore, water addition to the ethanol dehydration reactor may help preventing catalyst coking and diethyl ether formation, although affecting the thermodynamic products distribution. A proof of concept for an ethanol dehydration process using diluted ethanol is also provided through process simulation. Catalysts based on a BEA zeolite have been compared, characterised by different acidity imparted by dealumination treatments. Ni addition in variable loading helped suppressing undesired byproducts, difficult to separate from ethylene. For instance, no trace of diethyl ether nor acetaldehyde has been observed for the Ni-loaded samples under optimised working conditions. Catalyst characterisation by FT IR allowed correlating a high selectivity to ethylene with the acid sites nature of the catalyst, whereas the presence of extraframework Lewis acidic sites induced faster coke formation. Durability was finally checked on the most active and selective catalyst evidencing stable operation for 80 h-on-stream and without evidence of coke deposition, as determined after characterisation of the spent samples. A γ-Al2O3 catalyst has been tested as benchmark under the same conditions

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“…[23] The acidity of BEA-type β zeolites can be easily adjusted by eliminating lattice Al atoms from the framework. [24,25,26,27,28] Moreover, the left vacant T-atom sites associated with silanol groups in β zeolites after dealumination could accommodate and anchor metal species, [29,30,31] attributable to the reaction between metal species and silanol groups. [32,33] It has been reported the exchanged Zn 2 + ions or Zn(OH) + species in Al-containing zeolites are active for catalyzing PDH.…”

Section: Introductionmentioning

confidence: 99%

ZnO Nanoclusters Supported on Dealuminated Zeolite β as a Novel Catalyst for Direct Dehydrogenation of Propane to Propylene

et al. 2019

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Small ZnO nanoclusters supported on dealuminated β zeolite were prepared and evaluated for catalyzing direct dehydrogenation of propane to propylene (PDH), exhibiting high catalytic performance. N2 sorption, XRD, TEM, 27Al and 28Si MAS NMR, IR, XRF, DR UV‐vis, XPS, and NH3‐TPD techniques were employed to characterize the physicochemical properties of this novel catalyst system. It is found that the Zn species can be accommodated in the vacant T‐atom sites of dealuminated β zeolite due to the reaction of aqueous zinc acetate solution with silanol groups, and thus, producing massive small ZnO nanoclusters as active phases in PDH. Additionally, dealuminated β zeolite can greatly depress side reactions attributable to the absence of strong acid sites, thereby guaranteeing high catalytic activity, propylene selectivity and stability. As a result, the optimal catalyst of 10 wt% Zn loaded on dealuminated β zeolite exhibits a high initial propane conversion of around 53 % and a superior propylene selectivity of about 93 % at a space velocity of 4000 cm3 gcat−1 h−1, together with the high stability and satisfactory reusability. This study may open a new way to design and synthesize highly active PDH catalysts with high selectivity and stability.

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Influence of the nitric acid treatment on Al removal, framework composition and acidity of BEA zeolite investigated by XRD, FTIR and NMR

Cited by 110 publications

References 40 publications

One-pot conversion of furfural to useful bio-products in the presence of a Sn,Al-containing zeolite beta catalyst prepared via post-synthesis routes

One-pot conversion of furfural to useful bio-products in the presence of a Sn,Al-containing zeolite beta catalyst prepared via post-synthesis routes

Ethylene production via catalytic dehydration of diluted bioethanol: A step towards an integrated biorefinery

ZnO Nanoclusters Supported on Dealuminated Zeolite β as a Novel Catalyst for Direct Dehydrogenation of Propane to Propylene

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