scholarly journals Influence of Chemical Surface Characteristics of Ammonium-Modified Chilean Zeolite on Oak Catalytic Pyrolysis

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 465
Author(s):  
Serguei Alejandro-Martín ◽  
Adán Montecinos Acaricia ◽  
Cristian Cerda-Barrera ◽  
Hatier Díaz Pérez
Keyword(s):  
Catalytic Pyrolysis ◽  
Value Added ◽  
Surface Characteristics ◽  
Acid Sites ◽  
Bronsted Acid ◽  
X Ray ◽  
Chemical Surface ◽  
Brönsted Acid ◽  
Bio Oil ◽  
Modified Zeolites

The influence of chemical surface characteristics of Chilean natural and modified zeolites on Chilean Oak catalytic pyrolysis was investigated in this study. Chilean zeolite samples were characterised by nitrogen absorption at 77 K, X-ray powder diffraction (XRD), and X-ray fluorescence (XRF). The nature and strength of zeolite acid sites were studied by diffuse reflectance infrared Fourier transform (DRIFT), using pyridine as a probe molecule. Experimental pyrolysis was conducted in a quartz cylindrical reactor and bio-oils were obtained by condensation of vapours in a closed container. Chemical species in bio-oil samples were identified by a gas chromatography/mass spectrophotometry (GC/MS) analytical procedure. Results indicate that after the ionic exchange treatment, an increase of the Brønsted acid site density and strength was observed in ammonium-modified zeolites. Brønsted acids sites were associated with an increment of the composition of ketones, aldehydes, and hydrocarbons and to a decrease in the composition of the following families (esters; ethers; and acids) in obtained bio-oil samples. The Brønsted acid sites on ammonium-modified zeolite samples are responsible for the upgraded bio-oil and value-added chemicals, obtained in this research. Bio-oil chemical composition was modified when the pyrolysis-derived compounds were upgraded over a 2NHZ zeolite sample, leading to a lower quantity of oxygenated compounds and a higher composition of value-added chemicals.

scholarly journals Spatial differentiation of Brønsted acid sites by probe molecule in zeolite USY using synchrotron X-ray powder diffraction

2017 ◽  
Vol 53 (70) ◽  
pp. 9725-9728 ◽  
Author(s):  
Lin Ye ◽  
Ivo Teixeira ◽  
Benedict T. W. Lo ◽  
Pu Zhao ◽  
S. C. Edman Tsang
Keyword(s):  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Acid Site ◽  
Spatial Differentiation ◽  
Acid Sites ◽  
Probe Molecule ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
X Ray ◽  
Brönsted Acid

A direct correlation of extra-framework Al3+ in a sodalite cage (HY) with the enhanced Brønsted acid site evaluated by synchrotron X-ray powder diffraction, Rietveld refinement and the use of a pyridine probe molecule.

The Determination of Brønsted Acid Sites in Zeolite ERS-7 by Neutron and X-ray Powder Diffraction

2001 ◽  
Vol 105 (10) ◽  
pp. 1947-1955 ◽  
Author(s):  
B. J. Campbell ◽  
A. K. Cheetham ◽  
T. Vogt ◽  
L. Carluccio ◽  
W. O. Parker ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
X Ray ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

One-pot transformation of furfural into γ-valerolactone catalyzed by hierarchical Hf-Al-USY zeolite with balanced Lewis and Brønsted acid sites

2021 ◽  
Author(s):  
Bo Tang ◽  
Shuang Li ◽  
Wei-Chao Song ◽  
Yan Li ◽  
En-Cui Yang
Keyword(s):  
Lewis Acid ◽  
Value Added ◽  
Acid Sites ◽  
Bronsted Acid ◽  
Lewis Acid Sites ◽  
One Pot ◽  
Usy Zeolite ◽  
Brønsted Acid Sites ◽  
Brönsted Acid ◽  
Brønsted And Lewis Acid

Upgrading of furfural to high value-added chemicals are currently an attractive and challenging route in biorefineries. Herein, hierarchically structured bifunctional Hf-Al-USY zeolite with balanced Brønsted and Lewis acid sites has...

scholarly journals Elucidation of Adsorbate Structures and Interactions on Brønsted Acid Sites in H-ZSM-5 by Synchrotron X-ray Powder Diffraction

2016 ◽  
Vol 128 (20) ◽  
pp. 6085-6088 ◽  
Author(s):  
Benedict T. W. Lo ◽  
Lin Ye ◽  
Jin Qu ◽  
Junliang Sun ◽  
Junlin Zheng ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
X Ray ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

scholarly journals Influence of sulfating method on La–Ni–S2O82–/ZrO2–Al2O3 solid superacid catalyst for n-pentane isomerization

2020 ◽  
Vol 45 ◽  
pp. 146867831989772
Author(s):  
Haiqiang Zhao ◽  
Hua Song ◽  
Lele Zhao ◽  
Feng Li
Keyword(s):  
Infrared Spectroscopy ◽  
Pore Size ◽  
Pore Volume ◽  
Acid Sites ◽  
Impregnation Method ◽  
Bronsted Acid ◽  
Brønsted Acid Sites ◽  
X Ray ◽  
Brönsted Acid ◽  
Brönsted Acid Sites

La–Ni–S2O82–/ZrO2–Al2O3 catalysts were successfully prepared by two different methods of sulfate impregnation, and the physico-chemical properties of the catalysts were characterized by X-ray diffraction, Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, pyridine adsorption–infrared spectroscopy, and X-ray photoelectron spectroscopy techniques. Catalytic activities were evaluated in a fixed-bed flow reactor using n-pentane isomerization as the probe reaction. Compared with catalyst La–Ni–S2O82–/ZrO2–Al2O3-I, prepared by the traditional impregnation method, the catalyst La–Ni–S2O82–/ZrO2–Al2O3-W, prepared by the incipient-wetness impregnation method, possessed higher pore volume, pore size, sulfur content, and stronger Brønsted acid sites. The catalytic activity for La–Ni–S2O82–/ZrO2–Al2O3-W was maintained at around 56% within 3000 min with an isopentane selectivity of 88% which showed much greater stability than that of La–Ni–S2O82–/ZrO2–Al2O3-I. This can be attributed to the fact that (1) the large pore size and pore volume of La–Ni–S2O82–/ZrO2–Al2O3-W can largely suppress carbon deposition and (2) the more numerous and stronger Brønsted acid sites for La–Ni–S2O82–/ZrO2–Al2O3-W guaranteed to provide enough acid sites for isomerization during the reaction process.

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