Theoretical study of phenol and hydroxyl radical reaction mechanism in aqueous medium by the DFT/B3LYP/6-31+G(d,p)/CPCM model

Bhakthi, JayathilakaPavithra; Pathiraja, Gayani; BandaraAthula,; Deepal, SubasingheNalaka; Nanayakkara, N.

doi:10.1139/cjc-2014-0191

Cited by 25 publications

(14 citation statements)

References 21 publications

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“…Except for H-abs, the rate constants of the other ve reaction pathways in the aqueous phase were much higher than in the gas phase. Furthermore, the hydrogen abstraction rates of benzoic acid were much higher than for phenol (1.60 Â 10 À16 cm 3 per molecule per s), 49 since benzoic acid has an electronic withdrawing group, while phenol contains an electron donor group. 50 San et al calculated the reaction rate constants of benzoic acid with hydroxyl radical reaction in the aqueous phase, and the reaction rates were 8.38 Â 10 À11 , 4.20 Â 10 À8 , 1.65 Â 10 À20 , 5.08 Â 10 À24 cm 3 per molecule per s for meta addition reaction, ortho addition reaction, para addition reaction, and H-abs, respectively.…”

Section: Reaction Rate Constantsmentioning

confidence: 92%

Reactions of hydroxyl radicals with benzoic acid and benzoate

Visscher

Gates

2017

RSC Adv.

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Density functional theory was used to study the mechanism and kinetics of benzoic acid with hydroxyl radicals in both gas and aqueous phases as well as benzoate with hydroxyl radicals in the aqueous phase at the M06-2X/6-311+G(d,p) level of theory. The results show that all reaction pathways involved the formation of pre-reactive complexes which in turn alter reaction energy barriers. The reaction rate constants, calculated based on classical transitional theory, followed the order of meta addition > para addition > ortho addition for the reaction of benzoic acid and hydroxyl radicals in both gas and aqueous media. The energy barrier analysis reveals that the ortho adducts were also less vulnerable to subsequent reaction. In addition, the rate constants for the addition reactions were highest for benzoate in the aqueous phase, followed by benzoic acid in the aqueous phase, then by benzoic acid in the gas phase, consistent with electrostatic potential analysis. However, the rate constants of hydrogen abstraction in the aqueous phase were much lower than that in the gas phase and thus, gas phase reactions are preferred. The incorporation of one explicit water molecule, for addition reactions between benzoic acid and hydroxyl radicals, lowered reaction rates in the aqueous phase by increasing the bond length between the oxygen and reacting carbon in the benzene ring. rsc.li/rsc-advances 35776 | RSC Adv., 2017, 7, 35776-35785 This journal is Scheme 1 Reaction pathways of BA and BZ with hydroxyl radicals. (a) Reaction pathways of BA with hydroxyl radicals. (b) Reaction pathways of BZ with hydroxyl radicals. This journal is a Note: units for gas phase rate constants and aqueous phase rate constants are cm 3 per molecule per s À1 , and M À1 s À1 , respectively. 35782 | RSC Adv., 2017, 7, 35776-35785 This journal is

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Section: Reaction Rate Constantsmentioning

confidence: 92%

Reactions of hydroxyl radicals with benzoic acid and benzoate

Visscher

Gates

2017

RSC Adv.

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“…The HOMO/LUMO analysis will be helpful to determine whether the frontier orbitals between the BPF molecules and HO· match well. The previous study showed that the singly occupied molecular orbital (SOMO) of HO· is characteristic of π‐type orbital. From Supporting Information Figures S4 and S5, it can be found that both the HOMO and LUMO isosurfaces near the hydroxyls and benzenes in BPF molecules are π‐type orbitals and symmetrical to the SOMO of HO·.…”

Section: Resultsmentioning

confidence: 99%

“…For clarity, the Fukui function for radical attack was mapped onto the total electron density of each BPF molecule (Figure , isovalue = 0.0028 a.u.). The previous study showed that in phenol derivatives containing one phenolic ring, the C 2 , C 3 ,C 4 , C 5 , and C 6 (the number rules can be found in Figure ) are the active sites to accept the HO· attack. Here, based on the Fukui function analysis, it can be said that for most of the BPF molecules, the C 2 , C 3 , C 5 , and C 6 are active sites (the dark blue regions).…”

Section: Resultsmentioning

confidence: 99%

“…The main reactions between HO· and phenol or phenol derivatives are the hydrogen abstraction and addition reactions (Figure ). Berndt et al and Jayathilaka et al found that the HO· addition reactions are the dominant reactions. Morales‐Roque et al further proved that owing to the lower reaction barriers, the HO· addition reactions onto the ortho and para sites are dominant.…”

Section: Introductionmentioning

confidence: 99%

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Initial reaction mechanism between HO· and bisphenol‐F: Conformational dependence and the role of nonbond interactions

Bian

Wang

et al. 2017

Int J of Quantum Chemistry

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Hydroxyl radical (HO·) plays an important role in the initial pyrolysis of hydroxyl-containing polymers, such as phenolic resin (PR). In this study, the reaction mechanism between HO· and bisphenol-F (BPF) or tetra-methyl substituted BPFs, which were taken as the model molecules of PR, was studied with the density functional theory approach. The results based on the Fukui function and reduced density gradient function showed that, both the hydroxyls and the carbon atoms in the phenolic groups are the reactive sites for HO· attack. The hydroxyls are most likely to be attacked by HO· owing to the strong electrostatic potential around the hydroxyls and the low reaction barriers, especially for cis-o-o' type BPF. The strong pAp (CHAp and OHAp) interaction between the phenolic rings in BPF leads to decreased conjugative effect of the phenolic rings, which further lead to decreased addition barriers and reaction rate constant. K E Y W O R D S bisphenol-F, conformation, density functional theory, hydroxyl radical, reaction mechanism 1 | I N T R O D U C T I O N Bis(hydroxyphenyl)methanes, also named as bisphenol-Fs or BPFs, are a group of chemical compounds with two hydroxyphenyl functionalities bridged by one methylene group ( Figure 1). Owing to the structurally similarity to bisphenol-A, BPFs are desirable materials with many attractive applications paralleling bisphenol-A in use, such as the primary raw materials of epoxy, polycarbonate, or phenolic resins, but considerably lower toxicity than bisphenol-A. [1] However, the widespread application of BPFs also leads to considerable environmental problems. [2] A detailed investigation on the thermal decomposition mechanism of BPFs will be conducive to guiding the application and degradation of BPFs in reasonable ways. In particular, BPFs can also be regarded as the basic structural units or model compounds for phenolic resins (PRs), which are generally made from phenol and formaldehyde. [3] Hence, the elucidation of the thermal decomposition mechanism of BPF will be helpful for understanding the relationship of structural-thermal stability of PRs.The constitutional and conformational isomerism of BPFs lead to multiple structural characteristics of BPFs. There are three constitutional BPF isomers, 2,2 0 -bis(hydroxyphenyl)methane, 2,4 0 -bis(hydroxyphenyl)methane, and 4,4 0 -bis(hydroxyphenyl)methane (Figure 1), and this is also the primary reason for the rather complex crosslinked structure of PR. Wang et al.'s computational results [4] showed that there are more than 24 stable conformers of o-o' type BPF. Pillsbury et al. [5] stated that owing to the hydrogen bonds and OHAp interaction formation, the conformers with hydroxyls paralleled or perpendicular to each other are the dominant structures. Gruber et al. [6] proved that a p-p 0 type BPF conformer with the C 2 symmetry has the lowest energy, leading to a strong crystallinity of p-p 0 type BPF. In the highly crosslinked network of cured PR, most of the BPF-like structures are four methylene substituted BPFs, this fu...

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“…It has also been shown that this functional gives reasonable results for similar radical based studies. 23,39,[50][51][52][53] Additional calculations for the reaction mechanisms were performed using the ωB97XD 54 functional which has also been shown to give satisfactory results. [55][56][57][58] For the light atoms the 6-311+G(d,p) basis sets 59 were used, whereas LANL2TZ effective core potential basis set 60 was used for the iridium atom of the photocatalyst to account for relativistic effects.…”

Section: Methodsmentioning

confidence: 99%

Mechanism and Site Selectivity in Visible-Light Photocatalyzed C–H Functionalization: Insights from DFT Calculations

Demissie

Hansen

2016

J. Org. Chem.

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Visible-light photocatalyzed (VLPC) late-stage C-H functionalization is a powerful addition to the chemical synthesis toolkit. VLPC has a demonstrated potential for discovery of elusive and valuable transformations, particularly in functionalization of bioactive heterocycles. In order to fully harvest the potential of VLPC in the context of complex molecule synthesis, a thorough understanding of the elementary processes involved is crucial. This would enable more rational design of suitable reagents and catalysts, as well as prediction of activated C-H sites for functionalization. Such knowledge is essential when VLPC is to be employed in retrosynthetic analysis of complex molecules. Herein, we present a density functional theory (DFT) study of mechanistic details in the C-H functionalization of bioactive heterocycles exemplified by the methylation of the antifungal agent voriconazole. Moreover, we show that readily computed atomic charges can predict major site-selectivity in good agreement with experimental studies and thus be informative tools for the identification of active C-H functionalization sites in synthetic planning.

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Theoretical study of phenol and hydroxyl radical reaction mechanism in aqueous medium by the DFT/B3LYP/6-31+G(d,p)/CPCM model

Cited by 25 publications

References 21 publications

Reactions of hydroxyl radicals with benzoic acid and benzoate

Reactions of hydroxyl radicals with benzoic acid and benzoate

Initial reaction mechanism between HO· and bisphenol‐F: Conformational dependence and the role of nonbond interactions

Mechanism and Site Selectivity in Visible-Light Photocatalyzed C–H Functionalization: Insights from DFT Calculations

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