Density Functional Theory Rate Calculation of Hydrogen Abstraction Reactions of N-Phenyl-α-naphthylamine Antioxidants

Abstract

Quantum chemistry and transition state theory were used to investigate the hydrogen abstraction reaction of N-phenyl-α-naphthyl­amine with a series of alkyl­peroxy radicals. We correctly identify the transition state both in vacuum and under solvation before extracting a reaction rate constant using harmonic transition state theory. As expected, more polar solvents strongly reduce the rate constants. Our results compare favorably with the known experimental data and extend the database of reaction constants that can be used to simulate chemical kinetics for lubricant systems.

Theoretical Studies of the Hydrogen Abstraction from Poly(oxymethylene) Dimethyl Ethers by O2 in Relation with Cetane Number Data

“…Large varieties of computational methods indicate that the HF methods have been known to overestimate barrier heights, and pure DFT methods tend to underestimate the energy barrier. ,,− Hybrid DFT methods perform better for the computation of activation barriers than the pure DFT because of variation of the exact HF exchange energy term. ,, In particular, B3LYP is one of the most popular density functionals for a reasonable computational cost, , and the M06-2X functional has been shown to predict TS structures with small mean errors . In this work, kinetic parameters of H-abstraction reactions will be determined using the hybrid DFT methods B3LYP and M06-2X.…”

Machine Learning Applications for Chemical Reactions

“…In transition state theory, a reaction rate constant, k, is determined by differences of free energy between a reactant and transition state, and a quantum tunneling factor, κ [77,78] . The problem is that κ is not simply obtained from the fixed geometry, unlike free energy changes [79–82] …”

“…[75,76] In transition state theory, a reaction rate constant, k, is determined by differences of free energy between a reactant and transition state, and a quantum tunneling factor, k. [77,78] The problem is that k is not simply obtained from the fixed geometry, unlike free energy changes. [79][80][81][82] To obtain accurate k from an existing database, the Gaussian process model was trained and validated with actual experimental data. [83] The trained Gaussian process model predicts the scaling factor of the existing k from a traditional transition state theory.…”

The antioxidant activity and active sites of delphinidin and petunidin measured by DFT, in vitro chemical‐based and cell‐based assays

“…In addition, one of the main antioxidant mechanisms of anthocyanins was to remove radicals directly by HAT (Xu, Wang, Liu, Wang, & Wang, 2007). Antioxidant activity could be determined by the bond length, that is, the weaker the hydroxyl group bond length of anthocyanins, the more stable the semiquinone radical, and the stronger the antioxidant activity (Jabeen et al, 2018;Joly & Miller, 2018). Meanwhile, the active site and degree can be predicted by transition state energy barrier (Liao & Siegbahn, 2015), the bond length may reflect the activity of the bond, so the sites (O17, O20, O21, and O22 in delphinidin; O17, O21, and O22 in petunidin) were carried on the calculation of transition state.…”