Alkanolysis simulation of lignite-related model compounds using density functional theory

Li, Zhan-Ku; Zong, Zhi‐Min; Yan, Hong-Lei; Wang, Qianqian; Wei, Xian‐Yong; Shi, Da-Ling; Zhao, Yun‐Peng; Zhao, Chen; Yang, Zhusheng; Fan, Xing

doi:10.1016/j.fuel.2013.12.009

Cited by 21 publications

(6 citation statements)

References 26 publications

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“…7 Functional groups of ZL )naphthalene selected as lignite-related model compounds were subjected to ethanolysis using density functional theory according to our previous report. 30 Briefly, the method, functional, and basis set were set to generalized gradient approximation, Becke and Perdew functional, and double numerical plus polarization, respectively.…”

Section: Methodsmentioning

confidence: 99%

Effect of Ethanolysis on the Structure and Pyrolytic Reactivity of Zhaotong Lignite

Wei

Yan

et al. 2017

Energy Fuels

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Lignite ethanolysis is one of the efficient conversion processes. In our previous study, Zhaotong lignite (ZL) from Southwest China was subjected to ethanolysis to afford an ethanol-soluble portion and ethanolyzed residue (ER). The structural features of ZL and ER were investigated by ruthenium-ion-catalyzed oxidation (RICO) and Fourier transform infrared spectrometry. The pyrolytic reactivities of ZL and ER were examined with a thermogravimetric analyzer and Curie-point pyrolyzer–gas chromatograph/mass spectrometer. The results show that both ZL and ER are rich in −CH2CH2– and −CH2CH2CH2– bridged linkages connecting aromatic rings. In comparison to the RICO of ZL, the RICO of ER produced much less long-chain alkanoic and alkanedioic acids, suggesting that long alkylene bridges and alkyl side chains in ZL were largely cleaved via ethanolysis. Interestingly, ZL has a higher condensation degree than ER, which was confirmed by RICO and solid-state 13C nuclear magnetic resonance analysis. The result was explained by ethanolysis simulation of lignite-related model compounds using density functional theory. Thermogravimetric analysis of ZL and ER exhibits their different pyrolytic reactivities. According to analysis with a Curie-point pyrolyzer–gas chromatograph/mass spectrometer, significant differences in the distributions of the volatile species from the pyrolyses of ZL and ER were observed. Guaiacols and carbazoles are the most abundant group components from the pyrolyses of ZL and ER, respectively. ZL pyrolysis released much more alkanes and phenolic compounds than ER pyrolysis. The cleavage of Car–O bonds significantly proceeded during ZL ethanolysis.

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Section: Methodsmentioning

confidence: 99%

Effect of Ethanolysis on the Structure and Pyrolytic Reactivity of Zhaotong Lignite

Wei

Yan

et al. 2017

Energy Fuels

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“…To investigate the catalytic pyrolysis mechanism and give guidance for designing catalysts, plenty of theoretic works have been performed to study the reaction pathway. ,− As a result of the complexity, variability, and heterogeneity of coal, the coal-based model compounds have been widely used to study the pyrolysis behaviors of coal. C 6 H 5 COOH is a common model compound in the study of coal pyrolysis using density functional theory (DFT). ,, It is found that the direct decarboxylation mechanism and the stepwise decarboxylation mechanism are the main pathways of C 6 H 5 COOH pyrolysis. , According to the experimental results, the catalysts will affect the product distribution. − However, to our knowledge, no paper has studied the catalytic pyrolysis mechanism of coal-based model compound C 6 H 5 COOH on different catalysts.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on Catalytic Pyrolysis of Benzoic Acid as a Coal-Based Model Compound

et al. 2016

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Benzoic acid (C 6 H 5 COOH) is selected as a coal-based model compound, and its catalytic pyrolysis mechanisms on ZnO, γ-Al 2 O 3 , CaO, and MgO catalysts are studied using density functional theory (DFT) compared to the non-catalytic pyrolysis mechanism. DFT calculation shows that the pyrolysis process of C 6 H 5 COOH in the gas phase occurs via the direct decarboxylation pathway (C 6 H 5 COOH → C 6 H 6 + CO 2 ) or the stepwise decarboxylation pathway (C 6 H 5 COOH → C 6 H 6 COO → C 6 H 6 + CO 2 ). For C 6 H 5 COOH catalytic pyrolysis on the ZnO (101̅ 0) surface, the preferred reaction pathway is C 6 H 5 COOH → C 6 H 5 COO + H → C 6 H 6 + CO 2 , whereas the preferred reaction pathway on γ-Al 2 O 3 (110), CaO (100), and MgO (100) surfaces is C 6 H 5 COOH → C 6 H 5 COO + H → C 6 H 5 + CO 2 + H → C 6 H 6 + CO 2 , indicating that the presence of catalysts changed the pyrolysis mechanism of C 6 H 5 COOH. In addition, dissociative adsorption of C 6 H 5 COOH is observed on these surfaces. It is found that ZnO (101̅ 0), MgO (100), and CaO (100) are beneficial to C 6 H 5 COOH decomposition, but γ-Al 2 O 3 (110) is disadvantageous to the C 6 H 5 COOH decomposition. At the same reaction temperature, the rate constants show the order: k(ZnO) > k(MgO) > k(CaO) > k(no catalyst) > k(γ-Al 2 O 3 ).

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“…In our study, 33 docked complexes were obtained and five of them were further analyzed. The substrates were chosen on the bases of literature search [15][16][17][18] . Guaiacol, p-coumaric acid, sinapic acid (SA), fulvic acid and DMP were selected according to the best MOE docking score (Supplemental Table S1), economic and feasibility analysis of the use of such a compound in LMS (Fig.…”

Section: Resultsmentioning

confidence: 99%

Evolved Fusarium oxysporum laccase expressed in Saccharomyces cerevisiae

Kwiatos

Jędrzejczak-Krzepkowska

Krzemińska

et al. 2020

Sci Rep

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Fusarium oxysporum laccase was functionally expressed in Saccharomyces cerevisiae and engineered towards higher expression levels and higher reactivity towards 2,6-dimethoxyphenol, that could be used as a mediator for lignin modification. A combination of classical culture optimization and protein engineering led to around 30 times higher activity in the culture supernatant. The winner mutant exhibited three times lower Km, four times higher kcat and ten times higher catalytic efficiency than the parental enzyme. The strategy for laccase engineering was composed of a combination of random methods with a rational approach based on QM/MM MD studies of the enzyme complex with 2,6-dimethoxyphenol. Laccase mediator system with 2,6-dimethoxyphenol caused fulvic acids release from biosolubilized coal. Laccases are oxidoreductases that catalyze the 4-electron reduction of O 2 to water with simultaneous oxidation of organic substrates. Laccases are able to catalyze oxidation of a substrate of interest directly or indirectly by the formation of a radical, which then may take part in a non-enzymatic event that effects in the oxidation of a substrate of interest. Laccases oxidize phenolic substrates but are also able to oxidize non-phenolic or bigger substrates by Laccase Mediator System (LMS), where a small phenolic compound acts as a mediator 1. Laccases contain 4 copper atoms buried in their 3D structure, which are located in two separate Cu centers. T1 copper ion is a mononuclear center, whereas T2 copper ion and two T3 copper ions are positioned in T2/T3 copper center. The substrate is oxidized closed to T1 copper ion and then the electrons are transferred to the tri-nuclear center where O 2 is reduced to water. The coppers are coordinated by nearby located residues: the T1 copper ion by one Cys and two His residues, the T2 copper by two His residues and a solvent molecule and T3 copper to three His residues 2,3. Biosolubilization of brown coal is a clean coal technology that aims at the conversion of the lignite to its cleaner form or to change its structure to gain new features 4,5. Such solubilized material could be used as a source of value-added products 4. The liquid form of coal-microorganisms, such as Fusarium oxysporum reported before as an excellent coal solubilizer 6 , uses their metabolites, alkaline substances, biosurfactants and enzymes to turn the solid polymer to black liquid. Laccases, from bacteria and fungi, for example from species Pleurotus 7 or Streptomyces 8 , are known to take part in the degradation of lignin and lignite. These two polymers are similar in structure, thus, the mechanism of their degradation is expected to be the same. Lignin comprises only 10-20% of phenolic subunits. In theory, laccase could act on those subunits present on the lignin surface and modify the polymer. However, the possibility of lignin subunits entering the laccase active site is very limited. Moreover, it is not known to what extent lignin could be modified in this way 9. According to literature data, the treatme...

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Alkanolysis simulation of lignite-related model compounds using density functional theory

Cited by 21 publications

References 26 publications

Effect of Ethanolysis on the Structure and Pyrolytic Reactivity of Zhaotong Lignite

Effect of Ethanolysis on the Structure and Pyrolytic Reactivity of Zhaotong Lignite

Theoretical Study on Catalytic Pyrolysis of Benzoic Acid as a Coal-Based Model Compound

Evolved Fusarium oxysporum laccase expressed in Saccharomyces cerevisiae

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