DFT investigation on thermochemical analyses of conversion of xylose to linear alkanes in aqueous phase

Agrawal, Kushagra; Verma, Anand Mohan; Kishore, Nanda

doi:10.1016/j.jmgm.2019.05.005

Cited by 5 publications

(6 citation statements)

References 36 publications

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“…Similar to reaction (3) and ( 5), this decrease in ΔG at SC2 may have been caused due to offset of effect of solvation by the change in temperature-pressure which resulted in net increase in spontaneity. However, it has been reported by Agrawal et al 53 that the increase in temperature does not influence the spontaneity of the conversion in a significant way. Thus from SC1 to SC2, since the pressure is constant and temperature effect can be neglected, there is only solvation effect at play.…”

Section: Reactionmentioning

confidence: 84%

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Study of Conversion of Bio-oil Model Compounds in Supercritical Water Using Density Functional Theory

Agrawal

Kishore

2020

Sci Rep

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It is well known that supercritical water is a favourable medium for biomass conversion followed by its hydrodeoxygenation (HDO). Moreover, the actual kinetics and mechanism of reaction occurring in the supercritical water are not yet completely understood, either by experimental or computational approaches. Within the framework of DFT, the major challenge is non-availability of models to simulate supercritical phase. In this study, the authors manually define the descriptors of a solvation model to describe an implicit supercritical phase. In order to examine the suitability of supercritical water for thermal and hydrotreatment of bio-oil model compounds, nine different reactions involving conversion of furfural, tetrahydrofuran, xylose, phenol, guaiacol, ferulic acid, acetic acid, 2-hydroxybenzaldehyde and hydroxyacetone have been considered. Further these reactions are also studied in gas and liquid phase to compare results of different phases, including supercritical water. It was found that while HDO of aromatic compounds like phenol and 2-hydroxybenzaldehyde was favourable in the supercritical phase, smaller molecules like acetic acid and hydroxyacetone did not show much advantage in the supercritical phase over gas and liquid phase. It was also found that the thermochemical parameter - Gibbs free energy change (ΔG) was equally influenced by the solvation effect and the effect of temperature-pressure under supercritical conditions. In several instances, the two effects were found to offset each other in the supercritical phase.

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Section: Reactionmentioning

confidence: 84%

“…At SC1, it is found to be 24.14 kcal/mol and decrease to 14.24 kcal/mol at SC4 condition. However, in a different study conducted by same authors 53 , they found M06-2X and B3LYP functional to miserably fail in predicting free energy change of this reaction with the solvent model.…”

Section: Reactionmentioning

confidence: 91%

Study of Conversion of Bio-oil Model Compounds in Supercritical Water Using Density Functional Theory

Agrawal

Kishore

2020

Sci Rep

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“…18 Reaction pathways for the breakdown of xylose into valuable organic compounds have also been proposed under hydrothermal conditions. 19,20 However, a study of the mechanism of hemicellulose hydrolysis under alkali thermal pretreatment has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Study of the Mechanism of Hydrolysis of Hemicellulose from Lignocellulose during Alkali Thermal Pretreatment by Density Functional Theory and Experiment

Tian,

Mao,

et al. 2024

J. Org. Chem.

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The covalent bond fracture of hemicellulose leads to hemicellulose hydrolysis during lignocellulosic alkali thermal pretreatment, which has not previously been reported. Density functional theory was used to study the mechanism of hydrolysis of the hemicellulose model compounds under alkali conditions. There are four reaction paths for xylose formation, among which the reaction path with the lowest energy barrier is that in which the nucleophile captures H30 to generate water. The deprotonated hydroxyl group attacks the carbon on the glycoside bond, resulting in the cleavage of the glycoside bond and the formation of a new carbon−oxygen covalent bond, with an energy barrier of 154.2 kJ/mol. The nucleophile further attacks the glycosidic bond to form a new xylose residue with an energy barrier of 111.9 kJ/mol. When the glycosidic bond breaks, the orbital interaction with the largest proportion causes the transfer of ∼0.511 electron from the glycosidic bond oxygen to the deprotonated hydroxy oxygen. In situ Fourier transform infrared spectroscopy is used for the identification of functional groups during the alkali thermal pretreatment. As the temperature increases, the feasibility of the reaction increases. This study lays a theoretical foundation for the development of the alkali thermal pretreatment of lignocellulose.

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“…Consequently, this model has been widely used and accepted by researchers in various fields. [5][6][7][8][9] Even so, it should be noted that the commonly used QM/PCM technique combined with the quasi-ideal gas treatment (IGT) comprising calculations involving ideal gas/rigid rotor/harmonic oscillator models can lead to significant errors when deriving thermodynamic parameters for liquid-phase molecules. The contribution of solvent effects as obtained using a self-consistent reaction field is normally added to the electronic energy, and other contributions to H and S are corrected via the same formalism employed in the case of ideal gas-phase molecules.…”

Section: Introductionmentioning

confidence: 99%

Computation of entropy values for non-electrolyte solute molecules in solution based on semi-empirical corrections to a polarized continuum model

Izato

Matsugi

Koshi

et al. 2023

Phys. Chem. Chem. Phys.

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DFT investigation on thermochemical analyses of conversion of xylose to linear alkanes in aqueous phase

Cited by 5 publications

References 36 publications

Study of Conversion of Bio-oil Model Compounds in Supercritical Water Using Density Functional Theory

Study of Conversion of Bio-oil Model Compounds in Supercritical Water Using Density Functional Theory

Study of the Mechanism of Hydrolysis of Hemicellulose from Lignocellulose during Alkali Thermal Pretreatment by Density Functional Theory and Experiment

Computation of entropy values for non-electrolyte solute molecules in solution based on semi-empirical corrections to a polarized continuum model

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