Energetics, transition states, and intrinsic reaction coordinates for reactions associated with O(3P) processing of hydrocarbon materials

2004 ◽  
Vol 120 (19) ◽  
pp. 9253-9265 ◽  
Author(s):  
Tianying Yan ◽  
William L. Hase ◽  
Charles Doubleday
Keyword(s):  
Transition States ◽  
Reaction Coordinates

Pattern of Intrinsic Reaction Coordinates and Separatrices for a Symmetry-Forbidden Reaction

1986 ◽  
Vol 41 (3) ◽  
pp. 529-531 ◽  
Author(s):  
Ariel Fernández
Keyword(s):  
Structural Stability ◽  
Transition States ◽  
Chemical Species ◽  
Basins Of Attraction ◽  
Thermal Isomerization ◽  
Relative Distribution ◽  
Reaction Coordinates ◽  
Jahn Teller ◽  
Stability Principle ◽  
Good Agreement

The relative distribution of the basins of attraction of the chemical species and of the transition states is derived for the thermal isomerization of cyclobutene to butadiene.It is shown that the transition states for the symmetry-allowed and symmetry-forbidden pathways are lumomers of one another. Use is made of the structural stability principle of Ariel Fernández and Oktay Sinanoglu to show that these transition states are respectively the conrotatory and disrotatory Jahn-Teller distortions of the 2-butene diradical.The results exhibit good agreement with J. A. Berson’s conclusions in the sense that even the forbidden pathway is concerted.

The Decomposition Pathways of CH2SiCl3, CH3SiCl2 and CH2SiCl2 in CVD of SiC from MTS/H2 System

2013 ◽  
Vol 699 ◽  
pp. 378-382
Author(s):  
Xin Wang ◽  
Ke He Su ◽  
Yan Li Wang ◽  
Juan Li Deng
Keyword(s):  
Radical Reaction ◽  
Transition States ◽  
Heat Capacities ◽  
Free Radical Reaction ◽  
Electronic Correlation ◽  
Free Energies ◽  
Elementary Reactions ◽  
Reaction Coordinates ◽  
Reaction Energies ◽  
Accurate Model Chemistry

The decomposition pathways in CVD preparing SiC with CH3SiCl3-H2 precursors was searched theoretically, which involves 54 well-defined transition states. The geometries of the species were optimized by employing the B3PW91/6-311G(d,p) method. The transition states as well as their linked intermediates were confirmed with frequency and the intrinsic reaction coordinates analyses. The energy barriers and the reaction energies were evaluated with the accurate model chemistry method at G3(MP2) level after a non-dynamical electronic correlation detection. The heat capacities and entropies were obtained with statistical thermodynamics. The Gibbs free energies at 298.15 K and 1200 K for all of the reactions were reported. The energies at any temperature could be derived classically by using the analytical heat capacities. All the possible elementary reactions, including both direct decomposition and the radical attacking dissociations for CH2SiCl3, CH3SiCl2 and CH2SiCl2 were examined. A free radical reaction mechanism was proposed.

1994 R.U. Lemieux Award Lecture Hydrolysis of acetals and ketals. Position of transition states along the reaction coordinates, and stereoelectronic effects

1994 ◽  
Vol 72 (10) ◽  
pp. 2021-2027 ◽  
Author(s):  
Pierre Deslongchamps ◽  
Yves L. Dory ◽  
Shigui Li
Keyword(s):  
Ab Initio ◽  
Reaction Pathway ◽  
Transition States ◽  
Experimental Results ◽  
Reaction Coordinates ◽  
Stereoelectronic Effects ◽  
Theoretical Support ◽  
Semi Empirical ◽  
Hydrolysis Of ◽  
Support Evidence

Past and recent experimental results on the formation or hydrolysis (or isomerization) of various acetals and ketals including α-and β-glycoside models are presented. Ab initio investigations of simple acetals are also briefly reviewed as well as recent experimental and theoretical support evidence for a synperiplanar effect. A detailed study using the semi-empirical Hamiltonian AM1 defining the reaction pathway in the hydrolysis of various acetals and ketals is reported. This overall study shows that the hydrolysis of acetals and ketals is controlled by powerful stereoelectronic effects.

Theoretical Computations on the Pyrolysis of Alkyl (dithio)acetates

2020 ◽  
Vol 17 (3) ◽  
pp. 224-233
Author(s):  
Xun Zhu ◽  
Chen Jian ◽  
Xiuqin Zhou ◽  
Abdullah M. Asiri ◽  
Khalid A. Alamry ◽  
...  
Keyword(s):  
Transition States ◽  
Membered Ring ◽  
Pyrolysis Process ◽  
Alkyl Esters ◽  
Charge Distributions ◽  
Theoretical Analyses

The pyrolysis of methyl alkyl esters I to III and dithioesters IV to VI were theoretically calculated. All possible pyrolysis paths were considered. Both esters and dithioesters presented three potential paths via six-, four- and five-membered ring transition states, respectively. The calculation processes were calculated using MP2/6-31G(d) set. In-depth theoretical analyses were also presented, including NBO related analyses, synchronicities, and charge distributions, to reveal the detailed pyrolysis process.

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