scholarly journals Prediction of Mechanism and Thermochemical Properties of O3+ H2S Atmospheric Reaction

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Morteza Vahedpour ◽  
Reza Baghary ◽  
Freshte Khalili
Keyword(s):  
Hydrogen Sulfide ◽  
Reaction Mechanism ◽  
Oxygen Atom ◽  
Atmospheric Pressure ◽  
Vibrational Frequency ◽  
Main Reaction ◽  
Intrinsic Reaction Coordinate ◽  
Thermochemical Properties ◽  
Frequency Calculation ◽  
Atmospheric Reaction

Ozone and hydrogen sulfide reaction mechanism including a complex was studied at the B3LYP/6-311++G(3df,3pd) and CCSD/6-311++G(3df,3pd)//B3LYP/6-311++G(3df,3pd) levels of computation. The interaction between sulfur atom of hydrogen sulfide and terminal oxygen atom of ozone produces a stable H2S-O3complex with no barrier. With the decomposition of this complex, four possible product channels have been found. Intrinsic reaction coordinate, topological analyses of atom in molecule, and vibrational frequency calculation have been used to confirm the suggested mechanism. Thermodynamic data atT= 298.15 K and the atmospheric pressure have been calculated. The results show that the production of H2O + SO2is the main reaction channel with ΔG° = −645.84 kJ/mol. Rate constants of H2S + O3reaction show two product channels, SO2 + H2O and HSO + HOO, which compete with each other based on the temperature.

scholarly journals New Insight into the Chloroacetanilide Herbicide Degradation Mechanism through a Nucleophilic Attack of Hydrogen Sulfide

2018 ◽  
Vol 19 (10) ◽  
pp. 2864 ◽  
Author(s):  
José Mora ◽  
Cristian Cervantes ◽  
Edgar Marquez
Keyword(s):  
Hydrogen Sulfide ◽  
Reaction Mechanism ◽  
Activation Barrier ◽  
Degradation Mechanism ◽  
Reaction Force ◽  
Transition States ◽  
Reaction Coordinate ◽  
Basis Sets ◽  
Nucleophilic Attack ◽  
Intrinsic Reaction Coordinate

The nucleophilic attack of hydrogen sulfide (HS−) on six different chloroacetanilide herbicides was evaluated theoretically using the dispersion-corrected hybrid functional wB97XD and the 6-311++G(2d,2p) Pople basis sets. The six evaluated substrates were propachlor (A), alachlor (B), metolachlor (C), tioacetanilide (D), β-anilide (E), and methylene (F). Three possible mechanisms were considered: (a) bimolecular nucleophilic substitution (SN2) reaction mechanism, (b) oxygen assistance, and (c) nitrogen assistance. Mechanisms based on O- and N-assistance were discarded due to a very high activation barrier in comparison with the corresponding SN2 mechanism, with the exception of compound F. The N-assistance mechanism for compound F had a free activation energy of 23.52 kcal/mol, which was close to the value for the corresponding SN2 mechanism (23.94 kcal/mol), as these two mechanisms could occur in parallel reactions with almost 50% of each one. In compounds A to D, an important electron-withdrawing effect of the C=O and C=S groups was seen, and consequently, the activation free energies in these SN2 reactions were smaller, with a value of approximately 18 kcal/mol. Instead, compounds E and F, which have a CH2 group in the β-position, presented a higher activation free energy (≈22 kcal/mol). Good agreement was found between experimental and theoretical values for all cases, and a reaction force analysis was performed on the intrinsic reaction coordinate profile in order to gain more details about the reaction mechanism. Finally, from the natural bond orbital (NBO) analysis, it was possible to evaluate the electronic reorganization through the reaction pathway where all the transition states were early in nature in the reaction coordinate (δBav < 50%); the transition states corresponding to compounds A to D turned out to be more synchronous than those for compounds E and F.

scholarly journals Quantum chemical study of reaction mechanism between plutonium and Nitrogen

2021 ◽  
Author(s):  
Zhao-Yang Zhao ◽  
Guo-Liang Wang ◽  
Xu-Dan Chen ◽  
Chun-Bao Qi ◽  
Xin-Li Sun
Keyword(s):  
Reaction Mechanism ◽  
Potential Energy ◽  
Transition State ◽  
Density Functional ◽  
Transition States ◽  
Reaction Pathways ◽  
Stationary Points ◽  
Main Reaction ◽  
Intrinsic Reaction Coordinate ◽  
Phase Reaction

Abstract The study of the reaction between plutonium and nitrogen is helpful to further understand the interaction between plutonium and air gas molecules. For the nitridation reaction of plutonium, there is no report on the microscopic reaction mechanism of this system at present. Therefore, the microcospic mechanism of gas phase reaction of Pu with N 2 is studied in this paper based on the density functional theory (DFT) using different functions. In this paper, the geometry of stationary points on the potential energy surface is optimized. In addition, the transition states are verified by the frequency analysis method and the intrinsic reaction coordinate (IRC) method. Finally, we obtain the reaction potential energy curve and the micro reaction pathways. The analysis of reaction mechanism shows that the reaction of Pu with N 2 has two pathways. The pathway-1 (Pu+N 2 →R1→TS1→PuN 2 ) has a T-shaped transition state and the pathway-2 (Pu+N 2 →R 2 →TS 2 →PuN+N) has a L-shaped transition state. Moreover, both transition states have only one virtual frequency. The energy analysis shows that pathway-1 is the main reaction pathway. The nature of the Pu-N bonding evolution along the pathways is studied by atoms in molecules (AIM) and electron localization function (ELF) topological approaches. In order to analyse the role of 5f orbital of plutonium atom in the reaction, the variation of density of state along the pathways is performed. The results show that the 5f orbital makes major contributions to the formation of Pu-N bonds. Meanwhile, the influence of different temperatures on the reaction rate is revealed by calculating the rate constants of the two reaction pathways.

Reaction Mechanism of Atomic Layer Deposition of Aluminum Sulfide using Trimethylaluminum and Hydrogen Sulfide

2021 ◽  
Author(s):  
Yanghong Yu ◽  
Zhongchao Zhou ◽  
Lina Xu ◽  
Yihong Ding ◽  
Guoyong Fang
Keyword(s):  
Hydrogen Sulfide ◽  
Reaction Mechanism ◽  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Metal Sulfides ◽  
Layer Deposition

Atomic layer deposition (ALD) is a nanopreparation technique for materials and is widely used in the fields of microelectronics, energy and catalysis. ALD methods for metal sulfides, such as Al2S3...

Structural Characteristics of the Sulfur Linkage in Natural Rubber Vulcanizates

1957 ◽  
Vol 30 (2) ◽  
pp. 397-405 ◽  
Author(s):  
L. C. Bateman ◽  
R. W. Glazebrook ◽  
C. G. Moore ◽  
R. W. Saville
Keyword(s):  
Hydrogen Sulfide ◽  
Reaction Mechanism ◽  
Structural Characteristics ◽  
Complex Mixture ◽  
Open Chain ◽  
Organic Bases ◽  
Zinc Salts ◽  
Natural Rubber Vulcanizates ◽  
Polar Reaction ◽  
Cyclic Sulfide

Abstract Polyisoprenes react with sulfur both intramolecuarly and intermolecularly to yield cyclic sulfides and crosslinked sulfides, respectively. The structures of these have been examined for the reaction of the di-isoprene, 2,6-dimethylocta-2,6-diene, with sulfur at 140°. The cyclic sulfides consist of the two saturated compounds (I) and (II) and the two unsaturated compounds (III) and (IV). The crosslinked sulfide consists of a complex mixture in which unsaturated open chain and saturated and unsaturated cyclic sulfide structures have been identified. The structures of these products suggest a polar reaction mechanism, and also that hydrogen sulfide participates in the reaction. The influence of organic bases, the sulfurizing agent, reaction temperature, and zinc salts on the nature of the sulfur linkage is discussed.

Oxygen-Atom Vacancies Imaged by a Noncontact Atomic Force Microscope Operated in an Atmospheric Pressure of N2Gas

2004 ◽  
Vol 108 (40) ◽  
pp. 15735-15737 ◽  
Author(s):  
Akira Sasahara ◽  
Shin-ichi Kitamura ◽  
Hiroshi Uetsuka ◽  
Hiroshi Onishi
Keyword(s):  
Oxygen Atom ◽  
Atomic Force Microscope ◽  
Atmospheric Pressure ◽  
Atomic Force

Reaction mechanism of 1,2-hydrogen migration of hydrogen peroxide

1990 ◽  
Vol 68 (5) ◽  
pp. 666-673 ◽  
Author(s):  
Enric Bosch ◽  
José M. Lluch ◽  
Juan Bertrán
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Mechanism ◽  
Water Molecule ◽  
Energy Barrier ◽  
Electron Distribution ◽  
Reaction Path ◽  
Bifunctional Catalyst ◽  
Reaction Coordinate ◽  
Intrinsic Reaction Coordinate ◽  
Hydrogen Migration

The 1,2-hydrogen migration of hydrogen peroxide has been investigated by abinitio methods and the Intrinsic Reaction Coordinate (IRC) has been constructed. An analysis of the evolution of the electron distribution along the reaction path has shown that the shifting hydrogen behaves as a proton. This transferring proton polarizes the O—O bond of the hydrogen peroxide that becomes broken at the transition state. If a water molecule is allowed to participate in the reaction, the energy barrier is noticeably lowered, this water molecule acting as a bifunctional catalyst. Keywords: 1,2-hydrogen migration, hydrogen peroxide, proton transfer, bifunctional catalyst, Intrinsic Reaction Coordinate.

Stationary flames of methyl nitrate and methyl nitrite

1955 ◽  
Vol 232 (1190) ◽  
pp. 389-403 ◽  
Keyword(s):  
Nitric Oxide ◽  
Atmospheric Pressure ◽  
Burning Velocity ◽  
Vapour Phase ◽  
Main Reaction ◽  
Methyl Nitrite ◽  
Nitrate Esters ◽  
Methyl Nitrate ◽  
Low Pressures ◽  
Ethyl Nitrite

Methyl nitrate (CH 3 ONO 2 ) is the most explosive of the nitrate esters, and previous studies have been confined mainly to the slow thermal decomposition, and to the vapour phase explosion at low pressures in closed vessels. A stationary decomposition flame has now been maintained and studied spectrographically. A t low pressures the zones of reaction are clearly separated. From the early stages of the flame strong formaldehyde bands are emitted. This decomposition flame has been successfully simulated in artificial mixtures of methyl nitrite with oxygen. The results obtained are in accord with the preliminary fission of the nitrate molecule in the pre-heat zone of the flame: CH 3 ONO 2 →CH 3 O + NO 2 . The combustion flame of m ethyl nitrate with oxygen, nitric oxide and nitrogen dioxide has also been examined at low pressures. At atmospheric pressure, m ethyl nitrite (CH 3 ONO) has been found to support a decomposition flame of very small burning velocity. However, the combustion of m ethyl nitrite with oxygen at atmospheric pressure is an extremely fast and vigorous flame. It has been observed in both pre-mixed and diffusion systems and information about the changes occurring in it have been obtained by absorption and emission spectroscopy. All the experimental results may be interpreted in terms of two general principles: the reluctance of nitric oxide to react except at high temperatures and pressures and the frequent occurrence in flames of extensive pyrolytic reactions before the main reaction zone is reached.

Type 304 Stainless Steel vs Flowing CO2 At Atmospheric Pressure and 1100-1800F

CORROSION ◽  
1965 ◽  
Vol 21 (3) ◽  
pp. 84-94 ◽  
Author(s):  
H. E. McCOY
Keyword(s):  
Stainless Steel ◽  
Reaction Mechanism ◽  
Atmospheric Pressure ◽  
Oxidation Rate ◽  
Oxidation Process ◽  
Chromium Content ◽  
304 Stainless Steel ◽  
Type 304 ◽  
Type 304 Stainless Steel ◽  
Rate Controlling Step

Abstract Oxidation characteristics of Type 304 stainless steel in CO2 were observed over the temperature range 1100–1800 F (593–982 C). Although in general oxidation rate curves were parabolic, several periods were observed in which they were approximately linear. These breaks were reproducible and thought to be associated with changes in rate-controlling step of the oxidation process. Carburization of Type 304 stainless steel during exposure to CO2 was observed. Several other alloys were studied, to determine earbiorization mechanism. These included Type 406 stainless steel, a British 20 Cr– 25 Ni, niobium-stabilized steel, Inconel, iron, Fe–1 Cr, Fe–3 Cr, and Fe–10 Cr. Correlation was found between carburization and chromium content, with low chromium favoring and higher chromium inhibiting this reaction. Mechanism was proposed based upon influence of chromium on type of surface oxide formed.

Sign in / Sign up

Export Citation Format

Share Document