Reaction ergodography for dehydrogenation reaction of methanethiol

1985 ◽  
Vol 63 (7) ◽  
pp. 1532-1541 ◽  
Author(s):  
Tokio Yamabe ◽  
Cheng-Da Zhao ◽  
Masahiko Koizumi ◽  
Akitomo Tachibana ◽  
Kenichi Fukui
Keyword(s):  
Energy Surface ◽  
Intramolecular Interaction ◽  
Intrinsic Reaction Coordinate ◽  
Heat Of Reaction ◽  
Electronic Correlation ◽  
Mo Calculations ◽  
Dehydrogenation Reaction ◽  
Singlet Potential Energy Surface ◽  
Reactant Molecule ◽  
Dehydrogenation Reactions

The dehydrogenation reaction paths of methanethiol CH3SH were analyzed by abinitio MO calculations. The geometries and energies of the reactants, transition states, and products have been determined on the singlet potential energy surface of the ground state. We also analyze the similar dehydrogenation reactions of methanol (CH3OH) and ethanol (CH3CH2OH) for the purpose of comparison. The activation energy and the heat of reaction calculated by incorporating the effect of electronic correlation shows that the product H2C=S is chemically more unstable than the product H2C=O. "Reaction ergodography" along the intrinsic reaction coordinate (IRC) for these dehydrogenation paths clarifies the distinct differences in atomic movement. The path of methanethiol has two characteristic steps before the transition state, while neither paths of the two carbinols have such multisteps. The electronic intramolecular interaction between subsystems of the reactant molecule is investigated in terms of Interaction Hybrid Molecular Orbital (IHMO).

Theoretical Study of the Mechanism of the 1CBr2 + 3O2 Reaction

2011 ◽  
Vol 356-360 ◽  
pp. 31-34
Author(s):  
Cong Yun Shi ◽  
Jiao Zhang ◽  
Xing Zhong Liu
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Reaction Mechanisms ◽  
Energy Surface ◽  
Theoretical Study ◽  
Transition States ◽  
Reaction Coordinate ◽  
Intrinsic Reaction Coordinate ◽  
Singlet Potential Energy Surface

A detailed theoretical study was done in order to clarify the reaction mechanisms of the singlet dibromocarbene (1CBr2) with3O2on the singlet potential energy surface (PES). All the geometries of reactants, intermediates, transition states and products were obtained at the B3LYP/6-311++G(d,p) level. Intrinsic reaction coordinate (IRC) calculations at the same level were carried out to confirm the connections between transition states and intermediates. It is found that the initial adduct Br2COO (Cs) is formed via a barrierless association in the1CBr2+3O2reaction, and then some isomerizations and breakages of bonds take place, generating P1(BrCO + BrO), P2(CO + Br2O), P3(CO2+ Br2) and P4(CO2+ 2Br). P3(CO2+ Br2) is the most competitive channel kinetically and thermodynamically. P4(CO2+ 2Br) is the least favorable one kinetically.

Quantum modeling of the reaction between ozone and hydrogen cyanide

2017 ◽  
Vol 16 (07) ◽  
pp. 1750063
Author(s):  
Kahina Sidi Said ◽  
Madjid Nait Achour
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Thermodynamic Stability ◽  
Hydrogen Cyanide ◽  
Energy Surface ◽  
Topological Analysis ◽  
Reaction Pathways ◽  
Intrinsic Reaction Coordinate ◽  
Singlet Potential Energy Surface ◽  
Quantum Modeling

This work consists of an investigation, using current methods of quantum chemistry and, at first, on the basis of the available experimental results, about the new mechanisms of the reaction between ozone and hydrogen cyanide (HCN) in gaseous phases. Three possible reaction pathways which we have determined as the most probable and, all three, leading exactly to the same products, are proposed here. For each of these pathways, several steps for which we performed a kinetic study were identified in the singlet potential energy surface. To confirm the proposed mechanisms, we have achieved a study including the intrinsic reaction coordinate (IRC), the topological analysis of atoms in molecule and the harmonic vibrational frequencies calculations. The obtained results reveal that the final products have considerable thermodynamic stability and this reaction is exothermic in standard conditions.

scholarly journals On the 3D → 2D Isomerization of Hexaborane(12)

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 28-38
Author(s):  
Josep M. Oliva-Enrich ◽  
Ibon Alkorta ◽  
José Elguero ◽  
Maxime Ferrer ◽  
José I. Burgos
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Transition States ◽  
Three Dimensional ◽  
Reaction Coordinate ◽  
Intrinsic Reaction Coordinate ◽  
Limiting Factor ◽  
Two Dimensional ◽  
Axis Of Rotation

By following the intrinsic reaction coordinate connecting transition states with energy minima on the potential energy surface, we have determined the reaction steps connecting three-dimensional hexaborane(12) with unknown planar two-dimensional hexaborane(12). In an effort to predict the potential synthesis of finite planar borane molecules, we found that the reaction limiting factor stems from the breaking of the central boron-boron bond perpendicular to the C2 axis of rotation in three-dimensional hexaborane(12).

Studies of the Hard Rubber Reaction. I. Heat of Reaction

1963 ◽  
Vol 36 (4) ◽  
pp. 1059-1070 ◽  
Author(s):  
M. L. Bhaumik ◽  
D. Banerjee ◽  
Anil K. Sircar
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Sulfide ◽  
Differential Thermal Analysis ◽  
Exothermic Reaction ◽  
Heat Evolution ◽  
Linear Increase ◽  
Heat Of Reaction ◽  
Dehydrogenation Reaction ◽  
Rate Of Reaction

Abstract A method for the determination of the heat of the hard-rubber reaction by the application of differential thermal analysis is reported. The heat of reaction was determined with stocks containing different rubber/sulfur ratios and also with a 68/32 stock, preheated to contain different amounts of combined sulfur. Heat evolution is observed first with samples containing about 7 per cent sulfur and therefrom the amount of heat evolved shows a nearly linear increase up to 30 per cent sulfur. With increasing combined sulfur in the 68/32 stock, the quantity of exothermic heat gradually diminishes; so also does the temperature of initiation, i.e., the temperature at which heat evolution appears to begin. Initiation of the exothermic reaction appears to be a function of composition and temperature of the mass. An increase in the rate of reaction was observed when the composition reached 0.5 g-atom of sulfur per isoprene unit. An endothermic dehydrogenation reaction is observed at the end of the hard-rubber reaction. This, however, does not affect the determination of exothermic heat, because there is similar dehydrogenation taking place in the reference material (ebonite) which almost balances this heat loss. The final product has a lower sulfur content due to loss of sulfur as hydrogen sulfide.

Theoretical Study of the 1CHCl + 3O2 Reaction

2011 ◽  
Vol 356-360 ◽  
pp. 20-24
Author(s):  
Cong Yun Shi ◽  
Xing Zhong Liu ◽  
Da Xiao Xu ◽  
Zhi Gang Zhan
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Reaction Mechanisms ◽  
Energy Surface ◽  
Theoretical Study ◽  
Singlet Potential Energy Surface

Subscript textIn order to clarify the reaction mechanisms of the singlet monochlorocarbene radical (1 CHCl) with 3O2 on the singlet potential energy surface (PES), a detailed theoretical study was carried out at the B3LYP/6-311++G(d,p) level. It is found that the first step is the formation of the planar adducts HClCOO via a barrierless association in the 1 CHCl +3 O2 reaction, and then some isomerizations and breakages of bonds takSuperscript texte place, producing P1 (HCO + ClO), P2 (CO2 + HCl) and P3 (CO + HOCl). The product channel of P2 (CO2 + HCl) is the most competitive one both kinetically and thermodynamically. P1 (HCO + ClO) is the least favorable.

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