Relationship between activation energy and pre-exponential factor normalized by the number of Brønsted acid sites in cracking of short chain alkanes on zeolites

2015 ◽  
Vol 5 (3) ◽  
pp. 1864-1869 ◽  
Author(s):  
Naonobu Katada ◽  
Satoko Sota ◽  
Nami Morishita ◽  
Kazu Okumura ◽  
Miki Niwa
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Acid Sites ◽  
Short Chain ◽  
Activation Entropy ◽  
Bronsted Acid ◽  
Brønsted Acid Sites ◽  
Exponential Factor ◽  
Brönsted Acid ◽  
Alkane Cracking

Two different relationships between activation entropy and enthalpy in alkane cracking over various zeolites suggest a difference in the reaction mechanism.

scholarly journals Catalytic Ozonation of Toluene over Acidic Surface Transformed Natural Zeolite: A Dual-Site Reaction Mechanism and Kinetic Approach

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 958
Author(s):  
Serguei Alejandro-Martín ◽  
Héctor Valdés ◽  
Claudio A. Zaror
Keyword(s):  
Reaction Mechanism ◽  
Natural Zeolite ◽  
Surface Reaction ◽  
Acid Sites ◽  
Catalytic Ozonation ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Brönsted Acid ◽  
Brönsted Acid Sites

Volatile organic compounds (VOCs) are responsible for damage to health due to their carcinogenic effects. Catalytic ozonation using zeolite appears as a valuable process to eliminate VOCs from industrial emissions at room temperature. For full-scale application of this new abatement technology, an intrinsic reaction rate equation is needed for an effective process design and scale-up. Results obtained here provide a mechanistic approach during the initial stage of catalytic ozonation of toluene using an acidic surface transformed natural zeolite. In particular, the contribution of Lewis and Brønsted acid sites on the surface reaction mechanism and overall kinetic rate are identified through experimental data. The least-squares non-linear regression method allows the rate-determining step to be established, following a Langmuir–Hinshelwood surface reaction approximation. Experimental evidence suggest that ozone is adsorbed and decomposed at Lewis acid sites, forming active atomic oxygen that leads to the oxidation of adsorbed toluene at Brønsted acid sites.

scholarly journals On the Role of Protonic Acid Sites in Cu Loaded FAU31 Zeolite as a Catalyst for the Catalytic Transformation of Furfural to Furan

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2015
Author(s):  
Łukasz Kuterasiński ◽  
Małgorzata Smoliło-Utrata ◽  
Joanna Kaim ◽  
Wojciech Rojek ◽  
Jerzy Podobiński ◽  
...  
Keyword(s):  
Active Sites ◽  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Protonic Acid ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

The aim of the present paper is to study the speciation and the role of different active site types (copper species and Brønsted acid sites) in the direct synthesis of furan from furfural catalyzed by copper-exchanged FAU31 zeolite. Four series of samples were prepared by using different conditions of post-synthesis treatment, which exhibit none, one or two types of active sites. The catalysts were characterized by XRD, low-temperature sorption of nitrogen, SEM, H2-TPR, NMR and by means of IR spectroscopy with ammonia and CO sorption as probe molecules to assess the types of active sites. All catalyst underwent catalytic tests. The performed experiments allowed to propose the relation between the kind of active centers (Cu or Brønsted acid sites) and the type of detected products (2-metylfuran and furan) obtained in the studied reaction. It was found that the production of 2-methylfuran (in trace amounts) is determined by the presence of the redox-type centers, while the protonic acid sites are mainly responsible for the furan production and catalytic activity in the whole temperature range. All studied catalysts revealed very high susceptibility to coking due to polymerization of furfural.

scholarly journals Adsorption Thermodynamics and Intrinsic Activation Parameters for Monomolecular Cracking of n-Alkanes on Brønsted Acid Sites in Zeolites

2015 ◽  
Vol 119 (19) ◽  
pp. 10427-10438 ◽  
Author(s):  
Amber Janda ◽  
Bess Vlaisavljevich ◽  
Li-Chiang Lin ◽  
Shaama Mallikarjun Sharada ◽  
Berend Smit ◽  
...  
Keyword(s):  
Activation Parameters ◽  
Acid Sites ◽  
Adsorption Thermodynamics ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

Trimethylsilylation of Framework Brønsted Acid Sites in Microporous Zeolites and Silico-Aluminophosphates

2003 ◽  
Vol 125 (46) ◽  
pp. 13964-13965 ◽  
Author(s):  
Weiguo Song ◽  
David M. Marcus ◽  
Saifudin M. Abubakar ◽  
Emma Jani ◽  
James F. Haw
Keyword(s):  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

2,6-Dimethylpyridine as a probe of the strength of Brønsted acid sites: study on zeolites. Application to alumina

2005 ◽  
Vol 7 (8) ◽  
pp. 1861-1869 ◽  
Author(s):  
Laetitia Oliviero ◽  
Alexandre Vimont ◽  
Jean-Claude Lavalley ◽  
Francisca Romero Sarria ◽  
Marina Gaillard ◽  
...  
Keyword(s):  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

Quantification of Strong Brønsted Acid Sites in Aluminosilicates

2010 ◽  
Vol 114 (18) ◽  
pp. 8363-8374 ◽  
Author(s):  
Emiel J. M. Hensen ◽  
Dilip G. Poduval ◽  
D. A. J. Michel Ligthart ◽  
J. A. Rob van Veen ◽  
Marcello S. Rigutto
Keyword(s):  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites
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