Analysis of N-tert-Butoxy-Carboynl Anyhydride Formation Using Molecular Simulation
Estella Judith Salamula,
Misael Silas Nadiye-Tabbiruka
Issue:
Volume 4, Issue 3, November 2016
Pages:
14-20
Received:
29 October 2016
Accepted:
5 December 2016
Published:
23 December 2016
DOI:
10.11648/j.ijctc.20160403.11
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Abstract: Three dimensional structures of peptides: A, AG, AGA, AGAG and their cyclisation structures such as A-Cl, AG-Cl and their NCAs’ were drawn into a computer. Properties such as distance, angles, state surfaces were obtained and optimized to find the potential energy surface (PES), using a Gaussian program. These values were used to simulate the reaction of NCA formation from the precursor structures using their thermodynamic parameters’ (∆G, ∆H and ∆S) as a function of temperature, structure and length of the NCA precursor. The thermodynamic feasibility of the processes was investigated to augment work in the laboratory in view of the large number of applications including bio-organic synthesis and tissue engineering. Spontaneity of the reactions to form stable NCAs’ was found to increase with peptide length. The changes in thermodynamics, revealed more about the changes in energy with conformation in the reaction indicating that emphasis should be put on the general trends in the reaction, such that the increasingly negative values with length of molecules show increasing spontaneity of the reaction.
Abstract: Three dimensional structures of peptides: A, AG, AGA, AGAG and their cyclisation structures such as A-Cl, AG-Cl and their NCAs’ were drawn into a computer. Properties such as distance, angles, state surfaces were obtained and optimized to find the potential energy surface (PES), using a Gaussian program. These values were used to simulate the react...
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Theoretical Study of CH4 Adsorption and C-H Bond Activation of CH4 on Metal Ad-atom of M@M (111) (M=Ni, Pd, Pt, Cu, Ag, Au)
Tetsuya Ohkawa,
Kei Kuramoto
Issue:
Volume 4, Issue 3, November 2016
Pages:
21-30
Received:
29 November 2016
Accepted:
8 December 2016
Published:
10 January 2017
DOI:
10.11648/j.ijctc.20160403.12
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Abstract: We have investigated the CH4 adsorption and the C-H bond breaking activation on the metal ad-atom of M@M (111) (M=Ni, Pd, Pt, Cu, Ag, Au) and M@M (111)/H (covered by hydrogen atoms) 3 and 1-layer surfaces (4-type surfaces) using spin-polarized Density Functional Theory (DFT). We find that the adsorption energies of methane are related to the d-band center of metal ad-atoms. In particular, the distances between CH4 and Ni, Pd, and Pt ad-atoms of 4-type surfaces are shortened and the adsorption energies of CH4 on metal ad-atoms are stronger than the perfect surfaces because the d-band center of metal ad-atoms are close to the Fermi level. Furthermore, we have investigated the activation barrier energies of C-H bond breaking of CH4 on Ni, Pt, and Ag ad-atoms of 4-type surfaces because Pt ad-atom exhibits stronger adsorption energy of CH4, Ag ad-atom exhibits weaker ones, and Ni utilizes for the steam reforming reaction. We find that Ni and Pt ad-atoms show lower activation barrier energies, and they are related to the CH4 adsorption energies as well as the d-band centers.
Abstract: We have investigated the CH4 adsorption and the C-H bond breaking activation on the metal ad-atom of M@M (111) (M=Ni, Pd, Pt, Cu, Ag, Au) and M@M (111)/H (covered by hydrogen atoms) 3 and 1-layer surfaces (4-type surfaces) using spin-polarized Density Functional Theory (DFT). We find that the adsorption energies of methane are related to the d-band...
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First Principles Study of CO Adsorption on Atomic Pd Supported on Metal Oxide Surfaces (ZrO2 (110), MgO(100), CeO2(110))
Tetsuya Ohkawa,
Kei Kuramoto
Issue:
Volume 4, Issue 3, November 2016
Pages:
31-40
Received:
15 December 2016
Accepted:
30 December 2016
Published:
17 January 2017
DOI:
10.11648/j.ijctc.20160403.13
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Abstract: We have performed density functional theory (DFT) quantum periodic calculations to investigate the interaction between atomic Pd and oxide surfaces of ZrO2(110), MgO(100), and CeO2(110). In this calculation, Pd adsorption energy on the surface oxygen atom sites of those oxide surfaces correlated with the position of the d electron density center of Pd atom except for on the surface metal atom site. Furthermore, CO adsorption on Pd atoms adsorbed on the surface of those three kinds of oxide surfaces was investigated. The CO adsorption energy did not correlate with the position of d electron density center of Pd at the adsorption sites when they are summarized on each oxide surface but correlated with it when three kinds of oxide surface are grouped by adsorption site. Since Pd atom is the smallest size, it is easily influenced by oxide surface atoms and adsorbates. These results suggest that the nature of Pd atom adsorbed on oxide surface changes depending on where Pd atoms adsorb on the oxide surface, and is controlled by d electron density center.
Abstract: We have performed density functional theory (DFT) quantum periodic calculations to investigate the interaction between atomic Pd and oxide surfaces of ZrO2(110), MgO(100), and CeO2(110). In this calculation, Pd adsorption energy on the surface oxygen atom sites of those oxide surfaces correlated with the position of the d electron density center of...
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