Automated reaction mechanisms and kinetics based transition state search process AMK-gau_xtb and its application to the substitution reaction of the nitroso group in 2,4,6-trinitrotoluene by hydroxide anion in the aqueous phase

2021 ◽  
Author(s):  
Guan Zhang ◽  
Jin Li ◽  
Bo Long ◽  
Zongkuan Liu
Keyword(s):  
Transition State ◽  
Aqueous Phase ◽  
Alkaline Hydrolysis ◽  
Reaction Mechanisms ◽  
Substitution Reaction ◽  
Search Process ◽  
Nitroso Group ◽  
Hydrolysis Mechanism ◽  
Hydroxide Anion ◽  
Transition State Search

The newly developed AMK-gau_xtb discovers new TNT alkaline hydrolysis mechanism characteristics.

Effect of Medium on Reactivity for Alkaline Hydrolysis of p-Nitrophenyl Acetate and S-p-Nitrophenyl Thioacetate in DMSO-H2O Mixtures of Varying Compositions: Ground State and Transition State Contributions

2021 ◽  
Author(s):  
Ik-Hwan Um ◽  
Seungjae Kim
Keyword(s):  
Transition State ◽  
Alkaline Hydrolysis ◽  
Ground State ◽  
Rate Constants ◽  
Kinetic Data ◽  
Reaction Medium ◽  
Stepwise Mechanism ◽  
Rate Determining Step ◽  
Leaving Group ◽  
Hydrolysis Of

Second-order rate constants (kN) for reactions of p-nitrophenyl acetate (1) and S-p-nitrophenyl thioacetate (2) with OH‒ have been measured spectrophotometrically in DMSO-H2O mixtures of varying compositions at 25.0 ± 0.1 oC. The kN value increases from 11.6 to 32,800 M‒1s‒1 for the reactions of 1 and from 5.90 to 190,000 M‒1s‒1 for those of 2 as the reaction medium changes from H2O to 80 mol % DMSO, indicating that the effect of medium on reactivity is more remarkable for the reactions of 2 than for those of 1. Although 2 possesses a better leaving group than 1, the former is less reactive than the latter by a factor of 2 in H2O. This implies that expulsion of the leaving group is not advanced in the rate-determining transition state (TS), i.e., the reactions of 1 and 2 with OH‒ proceed through a stepwise mechanism, in which expulsion of the leaving group from the addition intermediate occurs after the rate-determining step (RDS). Addition of DMSO to H2O would destabilize OH‒ through electronic repulsion between the anion and the negative-dipole end in DMSO. However, destabilization of OH‒ in the ground state (GS) is not solely responsible for the remarkably enhanced reactivity upon addition of DMSO to the medium. The effect of medium on reactivity has been dissected into the GS and TS contributions through combination of the kinetic data with the transfer enthalpies (ΔΔHtr) from H2O to DMSO-H2O mixtures for OH‒ ion.

scholarly journals Electrochemistry as a Tool for Studies of Complex Reaction Mechanisms: The Case of the Atmospheric Aqueous-Phase Aging of Catechols

2019 ◽  
Vol 53 (19) ◽  
pp. 11195-11203 ◽  
Author(s):  
Kristijan Vidović ◽  
Ana Kroflič ◽  
Primož Jovanovič ◽  
Martin Šala ◽  
Irena Grgić
Keyword(s):  
Aqueous Phase ◽  
Reaction Mechanisms ◽  
Complex Reaction

Transition State Search Using a Guided Direct Inversion in the Iterative Subspace Method

2012 ◽  
Vol 8 (12) ◽  
pp. 5175-5179 ◽  
Author(s):  
Joseph W. May ◽  
Jeremy D. Lehner ◽  
Michael J. Frisch ◽  
Xiaosong Li
Keyword(s):  
Transition State ◽  
Subspace Method ◽  
Direct Inversion ◽  
Transition State Search

scholarly journals Nanodusty plasma chemistry: a mechanistic and variational transition state theory study of the initial steps of silyl anion–silane and silylene anion–silane polymerization reactions

2015 ◽  
Vol 17 (24) ◽  
pp. 15928-15935 ◽  
Author(s):  
Junwei Lucas Bao ◽  
Prasenjit Seal ◽  
Donald G. Truhlar
Keyword(s):  
Transition State ◽  
Reaction Mechanisms ◽  
Transition State Theory ◽  
Plasma Chemistry ◽  
State Theory ◽  
Variational Transition State Theory ◽  
Variational Transition State

The aim of the present work is to understand the detailed reaction mechanisms in the growth of nanodusty particles, which is critical in plasma chemistry, physics and engineering.

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