Determination of coke deposition on metal active sites of propane dehydrogenation catalysts

1997 ◽  
pp. 153-158 ◽  
Author(s):  
P. Praserthdam ◽  
T. Mongkhonsi ◽  
S. Kunatippapong ◽  
B. Jaikaew ◽  
N. Lim
Keyword(s):  
Active Sites ◽  
Propane Dehydrogenation ◽  
Coke Deposition

scholarly journals Bio-DEE Synthesis and Dehydrogenation Coupling of Bio-Ethanol to Bio-Butanol over Multicomponent Mixed Metal Oxide Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 660
Author(s):  
Izabela S. Pieta ◽  
Alicja Michalik ◽  
Elka Kraleva ◽  
Dusan Mrdenovic ◽  
Alicja Sek ◽  
...  
Keyword(s):  
Active Sites ◽  
Internal Combustion Engines ◽  
Mixed Oxides ◽  
Catalyst Activity ◽  
Product Distribution ◽  
Coke Deposition ◽  
Precipitation Method ◽  
Mixed Metal Oxide ◽  
Low Carbon ◽  
Municipal Solid Wastes

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods from municipal solid wastes (MSWs) are sought for application as energy carriers or direct drop-in fuels/chemicals in the near-future low-carbon power generation systems and internal combustion engines. Among the studied energy vectors, C1-C2 alcohols and ethers are mainly addressed. This study presents a potential bio-derived ethanol oxidative coupling in the gas phase in multicomponent systems derived from hydrotalcite-containing precursors. The reaction of alcohol coupling to ethers has great importance due to their uses in different fields. The samples have been synthesized by the co-precipitation method via layered double hydroxide (LDH) material synthesis, with a controlled pH, where the M(II)/M(III) ≈ 0.35. The chemical composition and topology of the sample surface play essential roles in catalyst activity and product distribution. The multiple redox couples Ni2+/Ni3+, Cr2+/Cr3+, Mn2+/Mn3+, and the oxygen-vacant sites were considered as the main active sites. The introduction of Cr (Cr3+/Cr4+) and Mn (Mn3+/Mn4+) into the crystal lattice could enhance the number of oxygen vacancies and affect the acid/base properties of derived mixed oxides, which are considered as crucial parameters for process selectivity towards bio-DEE and bio-butanol, preventing long CH chain formation and coke deposition at the same time.

Nonlinear Vibrations in a 2-Dimensional Protein Cluster Model with Linear Bonds

2000 ◽  
Vol 214 (1) ◽  
Author(s):  
E.G. Shidlovskaya ◽  
L. Schimansky-Geier ◽  
Yu.M. Romanovsky
Keyword(s):  
Active Site ◽  
Internal Resonance ◽  
Cluster Model ◽  
Active Sites ◽  
Nonlinear Vibrations ◽  
Nonlinear Phenomena ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Two Dimensional Model

A two dimensional model for the substrate inside a pocket of an active site of an enzyme is presented and investigated as a vibrational system. The parameters of the system are evaluated for α-chymotrypsin. In the case of internal resonance it is analytically and numerically shown that the energy concentrated on a certain degree of freedom might be several times larger than in the non-resonant case. Additionally, the system is driven by harmonic excitations and again energy due to nonlinear phenomena is redistributed inhomogeneously. These results may be of importance for the determination of the rates of catalytic events of substrates bound in pockets of active sites.

scholarly journals Calculation of the Global and Local Conceptual DFT Indices for the Prediction of the Chemical Reactivity Properties of Papuamides A–F Marine Drugs

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3312 ◽  
Author(s):  
Norma Flores-Holguín ◽  
Juan Frau ◽  
Daniel Glossman-Mitnik
Keyword(s):  
Density Functional Theory ◽  
Active Sites ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Active Regions ◽  
Conceptual Density Functional Theory ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Global And Local

A well-behaved model chemistry previously validated for the study of the chemical reactivity of peptides was considered for the calculation of the molecular properties and structures of the Papuamide family of marine peptides. A methodology based on Conceptual Density Functional Theory (CDFT) was chosen for the determination of the reactivity descriptors. The molecular active sites were associated with the active regions of the molecules related to the nucleophilic and electrophilic Parr functions. Finally, the drug-likenesses and the bioactivity scores for the Papuamide peptides were predicted through a homology methodology relating them with the calculated reactivity descriptors, while other properties such as the pKas were determined following a methodology developed by our group.

scholarly journals Determination of the Role and Active Sites of PKC-Delta-Like from Lamprey in Innate Immunity

2019 ◽  
Vol 20 (13) ◽  
pp. 3357
Author(s):  
Yang Xu ◽  
Huan Zhao ◽  
Yang Tian ◽  
Kaixia Ren ◽  
Nan Zheng ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Immune System ◽  
Innate Immune Response ◽  
Active Sites ◽  
Innate Immune ◽  
Pkc Delta ◽  
Kinase C ◽  
Catalytic Fragment

Protein kinase C-δ (PKC-δ) is an important protein in the immune system of higher vertebrates. Lampreys, as the most primitive vertebrates, have a uniquevariable lymphocyte receptor (VLR) immune system. PKC-δ-like is a crucial functional gene in lampreys and is highly expressed in their immune organs. In this study, lampreys were stimulated with different immunogens, and lipopolysaccharide (LPS) was found to increase the expression of PKC-δ-like. Overexpression of PKC-δ-like could also effectively activate the innate immune response. We further demonstrated that PKC-δ-like-CF, a catalytic fragment of PKC-δ-like, is responsible for activating the innate immune response, and Thr-211, which is Thr-419 of PKC-δ-like, was confirmed to be the key site affecting PKC-δ-like-CF activity. These results indicated that PKC-δ-like from lamprey may have an important role in the innate immune response.

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