Selective heterogeneous hydrodeoxygenation of acetophenone over monometallic and bimetallic Pt–Co catalyst

2021 ◽  
Vol 379 (2209) ◽  
pp. 20200346
Author(s):  
Natalia Pino ◽  
Jennifer Quinchia ◽  
Santiago Gómez ◽  
Juan F. Espinal ◽  
Alejandro Montoya ◽  
...  
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Bimetallic Catalyst ◽  
Advanced Materials ◽  
Theory Analysis ◽  
Theme Issue ◽  
Functional Theory ◽  
Co Catalyst ◽  
Bimetallic Systems ◽  
Products Of Reaction

The hydrodeoxygenation (HDO) of acetophenone was evaluated in liquid phase and gas phase over monometallic Pt/SiO 2 , Co/SiO 2 and bimetallic Pt–Co/SiO 2 catalysts. The influence of reaction time and loading of the catalyst were analysed by following the conversion and products selectivity. Phenylethanol, cyclohexylethanone and cyclohexylethanol are the main products of reaction using the Pt/SiO 2 catalyst. By contrast, ethylbenzene and phenylethanol are the only products formed on the Co/SiO 2 and Pt–Co/SiO 2 catalysts. The bimetallic catalyst is more stable as a function of time and more active towards the HDO process than the monometallic systems. The presence of an organic solvent showed only minor changes in product yields with no effect on the product speciation. Periodic density functional theory analysis indicates a stronger interaction between the carbonyl group of acetophenone with Co than with Pt sites of the mono and bimetallic systems, indicating a key activity of oxophilic sites towards improved selectivity to deoxygenated products. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.

scholarly journals Integrating single-cobalt-site and electric field of boron nitride in dechlorination electrocatalysts by bioinspired design

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuan Min ◽  
Xiao Zhou ◽  
Jie-Jie Chen ◽  
Wenxing Chen ◽  
Fangyao Zhou ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Electric Field ◽  
Active Sites ◽  
Density Functional ◽  
Electric Field Effect ◽  
Theory Analysis ◽  
Functional Theory ◽  
Co Catalyst ◽  
Carbon Doped ◽  
Organic Chloride

AbstractThe construction of enzyme-inspired artificial catalysts with enzyme-like active sites and microenvironment remains a great challenge. Herein, we report a single-atomic-site Co catalyst supported by carbon doped boron nitride (BCN) with locally polarized B–N bonds (Co SAs/BCN) to simulate the reductive dehalogenases. Density functional theory analysis suggests that the BCN supports, featured with ionic characteristics, provide additional electric field effect compared with graphitic carbon or N-doped carbon (CN), which could facilitate the adsorption of polarized organochlorides. Consistent with the theoretical results, the Co SAs/BCN catalyst delivers a high activity with nearly complete dechlorination (~98%) at a potential of −0.9 V versus Ag/AgCl for chloramphenicol (CAP), showing that the rate constant (k) contributed by unit mass of metal (k/ratio) is 4 and 19 times more active than those of the Co SAs/CN and state-of-the-art Pd/C catalyst, respectively. We show that Co single atoms coupled with BCN host exhibit high stability and selectivity in CAP dechlorination and suppress the competing hydrogen evolution reaction, endowing the Co SAs/BCN as a candidate for sustainable conversion of organic chloride.

Intrinsic Stacking Interactions of Natural and Artificial Nucleobases

2019 ◽  
Author(s):  
Drew P. Harding ◽  
Laura J. Kingsley ◽  
Glen Spraggon ◽  
Steven Wheeler
Keyword(s):  
Gas Phase ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Molecular Descriptors ◽  
Stacking Interactions ◽  
Interaction Energies ◽  
Functional Theory ◽  
Binding Partner ◽  
Heavy Atoms ◽  
Wide Range

The intrinsic (gas-phase) stacking energies of natural and artificial nucleobases were explored using density functional theory (DFT) and correlated ab initio methods. Ranking the stacking strength of natural nucleobase dimers revealed a preference in binding partner similar to that seen from experiments, namely G > C > A > T > U. Decomposition of these interaction energies using symmetry-adapted perturbation theory (SAPT) showed that these dispersion dominated interactions are modulated by electrostatics. Artificial nucleobases showed a similar stacking preference for natural nucleobases and were also modulated by electrostatic interactions. A robust predictive multivariate model was developed that quantitively predicts the maximum stacking interaction between natural and a wide range of artificial nucleobases using molecular descriptors based on computed electrostatic potentials (ESPs) and the number of heavy atoms. This model should find utility in designing artificial nucleobase analogs that exhibit stacking interactions comparable to those of natural nucleobases. Further analysis of the descriptors in this model unveil the origin of superior stacking abilities of certain nucleobases, including cytosine and guanine.

Graph theory-based reaction pathway searches and DFT calculations for the mechanism studies of free radical-initiated peptide sequencing mass spectrometry (FRIPS MS): a model gas-phase reaction of GGR tri-peptide

2020 ◽  
Vol 22 (9) ◽  
pp. 5057-5069 ◽  
Author(s):  
Jae-ung Lee ◽  
Yeonjoon Kim ◽  
Woo Youn Kim ◽  
Han Bin Oh
Keyword(s):  
Graph Theory ◽  
Dft Calculations ◽  
Gas Phase ◽  
Density Functional ◽  
Reaction Pathway ◽  
Peptide Sequencing ◽  
Phase Reaction ◽  
Functional Theory ◽  
Fragmentation Mechanisms ◽  
Gas Phase Fragmentation

A new approach for elucidating gas-phase fragmentation mechanisms is proposed: graph theory-based reaction pathway searches (ACE-Reaction program) and density functional theory (DFT) calculations.

Exploring chemistry features of favipiravir in octanol/water solutions

2021 ◽  
pp. 1-12
Author(s):  
Halimeh Rajabzadeh ◽  
Ayla Sharafat ◽  
Maryam Abbasi ◽  
Maryam Eslami Gharaati ◽  
Iraj Alipourfard
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Partition Coefficients ◽  
Density Functional ◽  
Water Solution ◽  
Peptide Group ◽  
Functional Theory ◽  
Water Solutions ◽  
Group Rotations ◽  
Heterocyclic Structure

Favipiravir (Fav) has become a well-known drug for medication of patients by appearance of COVID-19. Heterocyclic structure and connected peptide group could make changes for Fav yielding different features from those required features. Therefore, it is indeed a challenging task to prepare a Fav compound with specific features of desired function. In this work, existence of eight Fav structures by tautomeric formations and peptide group rotations were obtained using density functional theory (DFT) optimization calculations. Gas phase, octanol solution, and water solution were employed to show impact of solution on features of Fav besides obtaining partition coefficients (LogP) for Fav compounds. Significant impacts of solutions were seen on features of Fav with the obtained LogP order: Fav-7 >  Fav-8 >  Fav-4 >  Fav-3 >  Fav-2 >  Fav-5 >  Fav-1 >  Fav-6. As a consequence, internal changes yielded significant impacts on features of Fav affirming its carful medication of COVID-19 patients.

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