Investigating the influence of acid sites in continuous methane oxidation with N2O over Fe/MFI zeolites

The effect of modification of MFI zeolite 1–5 wt.% ZnO activated by plasma on acid and catalytic properties in the conversion of the propane–butane fraction into arenes was investigated. The high-silica zeolites with silicate module 45 were synthesized from alkaline alumina–silica gels in the presence of an ‘X-oil’ organic structure-forming additive. The modification of the zeolite with zinc was carried out by impregnating the zeolite granules in the H-form with an aqueous solution of Zn(NO3)2. The obtained zeolites were characterized by X-ray phase analysis and IR spectroscopy. It is shown that the synthesized zeolites belong to the high-silica MFI zeolites. The study of microporous zeolite-containing catalysts during the conversion of C3-C4 alkanes to aromatic hydrocarbons made it possible to establish that the highest yield of aromatic hydrocarbons is observed on zeolite catalysts modified with 1 and 3% ZnO and amount to 63.7 and 64.4% at 600 °C, respectively, which is 7.7–8.4% more than on the original zeolite. The preliminary activation of microporous zeolites modified with 1–5% ZnO and plasma leads to an increase in the yield of aromatic hydrocarbons from the propane–butane fraction; the maximum yield of arenes is observed in zeolite catalysts modified with 1 and 3% ZnO and activated by plasma, amounting to 64.9 and 65.5% at 600 °C, respectively, which is 8.9–9.5% more than on the initial zeolite. The activity of the zeolite catalysts modified by ZnO and activated by plasma show good agreement with their acid properties. Activation of the zeolites modified by 1 and 3% ZnO and plasma leads to an increase in the concentration of the weak acid sites of the catalyst to 707 and 764 mmol/g in comparison with plasma-inactivated 1 and 3% ZnO/ZKE-XM catalysts at 626 and 572 mmol/g, respectively.

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Selective Production of Aromatics from 2-Octanol on Zinc Ion-Exchanged MFI Zeolite Catalysts

Catalysts ◽

10.3390/catal5042122 ◽

2015 ◽

Vol 5 (4) ◽

pp. 2122-2133 ◽

Cited By ~ 2

Author(s):

Masakazu Iwamoto ◽

Ryota Takezawa ◽

Masao Morimoto

Keyword(s):

Zinc Ion ◽

Zeolite Catalysts ◽

Mfi Zeolite

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Solvent-Free Synthesis of SAPO-34 Zeolite with Tunable SiO2/Al2O3 Ratios for Efficient Catalytic Cracking of 1-Butene

Catalysts ◽

10.3390/catal11070835 ◽

2021 ◽

Vol 11 (7) ◽

pp. 835

Author(s):

Xia Xiao ◽

Zhongliang Xu ◽

Peng Wang ◽

Xinfei Liu ◽

Xiaoqiang Fan ◽

...

Keyword(s):

Catalytic Cracking ◽

Acid Sites ◽

Solvent Free ◽

Zeolite Catalysts ◽

Light Olefins ◽

Molar Ratio ◽

Coordination Environment ◽

Starting Mixture ◽

Synthesis Methodology ◽

Solvent Free Synthesis

Solvent-free synthesis methodology is a promising technique for the green and sustainable preparation of zeolites materials. In this work, a solvent-free route was developed to synthesize SAPO-34 zeolite. The characterization results indicated that the crystal size, texture properties, acidity and Si coordination environment of the resulting SAPO-34 were tuned by adjusting the SiO2/Al2O3 molar ratio in the starting mixture. Moreover, the acidity of SAPO-34 zeolite was found to depend on the Si coordination environment, which was consistent with that of SAPO-34 zeolite synthesized by the hydrothermal method. At an SiO2/Al2O3 ratio of 0.6, the SP-0.6 sample exhibited the highest conversion of 1-butene (82.8%) and a satisfactory yield of light olefins (51.6%) in the catalytic cracking of 1-butene, which was attributed to the synergistic effect of the large SBET (425 m2/g) and the abundant acid sites (1.82 mmol/g). This work provides a new opportunity for the design of efficient zeolite catalysts for industrially important reactions.

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Study of active sites on the MFI zeolite catalysts for the transformation of ethanol into propylene

Journal of Molecular Catalysis A Chemical ◽

10.1016/j.molcata.2010.06.008 ◽

2010 ◽

Vol 328 (1-2) ◽

pp. 114-118 ◽

Cited By ~ 37

Author(s):

Wei Xia ◽

Atsushi Takahashi ◽

Isao Nakamura ◽

Hiromichi Shimada ◽

Tadahiro Fujitani

Keyword(s):

Active Sites ◽

Zeolite Catalysts ◽

Mfi Zeolite

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Synthesis of Uniform Mesoporous Zeolite ZSM-5 Catalyst for Friedel-Crafts Acylation

ChemEngineering ◽

10.3390/chemengineering3020035 ◽

2019 ◽

Vol 3 (2) ◽

pp. 35 ◽

Cited By ~ 10

Author(s):

Heman Smail ◽

Mohammad Rehan ◽

Kafia Shareef ◽

Zainab Ramli ◽

Abdul-Sattar Nizami ◽

...

Keyword(s):

Surface Area ◽

Surface Acidity ◽

Analytical Techniques ◽

Acid Sites ◽

Zeolite Catalysts ◽

Gas Chromatography Mass Spectrometry ◽

Crystallographic Structure ◽

Mesoporous Zeolite ◽

Mesoporous Zeolites ◽

Surfactant Templates

This work highlights how the treatment of ZSM-5 (parent Zeolite Socony Mobil–5, Si/Al = 23) with different surfactant templates and alkaline solution, improved the catalytic performance in the Friedel-Crafts acylation of anisole with a propionic anhydride to obtain p-methoxypropiophenone. The modified microporous to mesoporous zeolite catalysts were characterized using different analytical techniques, including X-ray diffraction (XRD), nitrogen porosimetry, Fourier-transform infrared spectroscopy (FT-IR), temperature-programmed desorption (ammonia-TPD) and field emission scanning electron microscopy (FE-SEM) to analyze the crystallographic structure, surface acidity, surface area, porosity, morphology, and particle size. The results showed that the formed mesoporous zeolite by NaOH solution had smaller mesopores (ca. 3.7 nm) as compared to the mesoporous zeolites obtained by surfactant templates, such as, CTAB (ca. 14.9 nm), TPAOH (ca. 11.1 nm) and mixture of CTAB/TPAOH (ca. 15.2 nm). The catalytic acylation reaction was conducted in a batch glass reactor at various temperatures and the products were analyzed using off-line gas chromatography–mass spectrometry (GC-MS). It was found that the activity of treated ZSM-5 with mixed surfactant templates (CTAB/TPAOH) exhibited enhanced selectivity towards the main product (p-methoxypropiophenone) by a factor 1.7 or higher than unmodified ZSM-5 due to its increased surface area by 1.5 times and enhanced acid sites.

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Mechanism of intra- and inter-molecular CC bond formation of propanal on Brønsted acid sites contained within MFI zeolites

Journal of Catalysis ◽

10.1016/j.jcat.2013.11.018 ◽

2014 ◽

Vol 311 ◽

pp. 244-256 ◽

Cited By ~ 16

Author(s):

Fan Lin ◽

Ya-Huei (Cathy) Chin

Keyword(s):

Bond Formation ◽

Acid Sites ◽

Bronsted Acid ◽

Brønsted Acid ◽

Brønsted Acid Sites ◽

Brönsted Acid ◽

Brönsted Acid Sites ◽

Bronsted Acid Sites ◽

Mfi Zeolites

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Aqueous-Phase Methane Oxidation over Fe-MFI Zeolites; Promotion through Isomorphous Framework Substitution

ACS Catalysis ◽

10.1021/cs400288b ◽

2013 ◽

Vol 3 (8) ◽

pp. 1835-1844 ◽

Cited By ~ 57

Author(s):

Ceri Hammond ◽

Nikolaos Dimitratos ◽

Jose Antonio Lopez-Sanchez ◽

Robert L. Jenkins ◽

Gareth Whiting ◽

...

Keyword(s):

Methane Oxidation ◽

Aqueous Phase ◽

Mfi Zeolites

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CuZnZr-Zeolite Hybrid Grains for DME Synthesis: New Evidence on the Role of Metal-Acidic Features on the Methanol Conversion Step

Catalysts ◽

10.3390/catal10060671 ◽

2020 ◽

Vol 10 (6) ◽

pp. 671

Author(s):

Massimo Migliori ◽

Antonio Condello ◽

Francesco Dalena ◽

Enrico Catizzone ◽

Girolamo Giordano

Keyword(s):

Acid Catalyst ◽

Methanol Conversion ◽

Catalytic Performance ◽

Acid Sites ◽

Zeolite Catalysts ◽

Hybrid Catalyst ◽

Zeolite Structure ◽

Precipitation Medium ◽

Co Precipitation ◽

New Evidence

The assessment of the catalytic performance of “hybrid” metal/zeolite catalysts (based on FER or MFI structure and CuZnZr metal complexes) in the methanol dehydration step to DME has been studied in this work. The results clearly show that there is an important effect of the interaction between metal and acid sites affecting the acid catalyst performances. Additionally, deactivation, studied by means of a Timo-on-Stream (TOS) test, was affected by the type of zeolite structure used for hybrid catalyst preparation. The decrease in DME selectivity can be attributed to the cooperation of metal and acid sites in the production of different compounds (mainly methyl formate and dimethoxy methane) converting methanol and DME. The presence of these compounds (indicating different reaction pathways active) was found to be dependent on the zeolite structure and on the type of co-precipitation medium (water or ethanol) used to prepare the hybrid catalyst.

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