1
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Monção M, Wretborn T, Rova U, Matsakas L, Christakopoulos P. Salicornia dolichostachya organosolv fractionation: towards establishing a halophyte biorefinery. RSC Adv 2022; 12:28599-28607. [PMID: 36320546 PMCID: PMC9540244 DOI: 10.1039/d2ra04432c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/27/2022] [Indexed: 11/07/2022] Open
Abstract
Halophytes are a potential source of lignocellulosic material for biorefinery, as they can be grown in areas unsuitable for the cultivation of crops aimed at food production. To enable the viable use of halophytes in biorefineries, the present study investigated how different organosolv process parameters affected the fractionation of green pressed fibers of Salicornia dolichostachya. We produced pretreated solids characterized by up to 51.3% ± 1.7% cellulose, a significant increase from 25.6% ± 1.3% in untreated fibers. A delignification yield of as high as 60.7%, and hemicellulose removal of as high as 86.1% were also achieved in the current study. The obtained cellulose could be completely converted to glucose via enzymatic hydrolysis within 24 h. The lignin fractions obtained were of high purity, with sugar contamination of only 1.22% w/w and ashes below 1% w/w in most samples. Finally, up to 29.1% ± 0.4% hemicellulose was recovered as a separate product, whose proportion of oligomers to total sugars was 69.9% ± 3.0%. To the best of our knowledge, this is the first report in which Salicornia fibers are shown to be a suitable feedstock for organosolv biomass fractionation. These results expand the portfolio of biomass sources for biorefinery applications. An organosolv method was developed for the fractionation of fibers of a halophyte plant in a biorefinery approach. Salicornia dolichostachya was used as raw material allowing the production of cellulose, hemicellulose, and lignin fractions.![]()
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Affiliation(s)
- Maxwel Monção
- Department of Civil, Environmental and Natural Resources Engineering, Luleå Tekniska UniversitetSE-971 87LuleåSweden+46 (0) 920 493043
| | - Tobias Wretborn
- Department of Civil, Environmental and Natural Resources Engineering, Luleå Tekniska UniversitetSE-971 87LuleåSweden+46 (0) 920 493043
| | - Ulrika Rova
- Department of Civil, Environmental and Natural Resources Engineering, Luleå Tekniska UniversitetSE-971 87LuleåSweden+46 (0) 920 493043
| | - Leonidas Matsakas
- Department of Civil, Environmental and Natural Resources Engineering, Luleå Tekniska UniversitetSE-971 87LuleåSweden+46 (0) 920 493043
| | - Paul Christakopoulos
- Department of Civil, Environmental and Natural Resources Engineering, Luleå Tekniska UniversitetSE-971 87LuleåSweden+46 (0) 920 493043
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2
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Dege N, Özge Ö, Avcı D, Başoğlu A, Sönmez F, Yaman M, Tamer Ö, Atalay Y, Zengin Kurt B. Concentration effects on optical properties, DFT, crystal characterization and α-glucosidase activity studies: Novel Zn(II) complex. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 262:120072. [PMID: 34175761 DOI: 10.1016/j.saa.2021.120072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/02/2021] [Accepted: 06/09/2021] [Indexed: 06/13/2023]
Abstract
A novel Zn(II) complex of 6-ClpicH and picH was synthesized and its structure was determined by XRD technique. The detailed experimental optical susceptibility and band gap, refractive index, linear polarizability, optical and electrical conductivity parameters in various concentrations were investigated by means of the UV-Vis spectroscopic data. The optical band gap, refractive index (n), linear optical susceptibility (χ(1)), third-order nonlinear optical susceptibility (χ(3)), second- and third-order nonlinear optical (β and γ) parameters were examined by using DFT/M06-L and ωB97XD/6-311++G(d,p) levels. The IC50 value of Zn(II) complex against α-glucosidase was also obtained at 0.44 mM. The experimental band gap of the Zn(II) complex at 13, 33, 44 and 94 µM concentrations in ethanol were found to be 4.38, 4.37, 4.35 and 4.28 eV, respectively. The third-order NLO susceptibility χ(3) parameter at 94 µM concentration corresponding to the photon energies of 4.6 and 5.7 eV in the UV-Vis region were observed at 206.6 × 10-13 and 294.3 × 10-13 esu, respectively. Besides, the theoretical χ(3) values were obtained at 50.58 × 10-13 and 20.37 × 10-13 esu by using M06-L level. These results indicate that Zn(II) complex could be an effective third-order NLO candidate material. In brief, the detailed theoretical and experimental structural, spectral and optical properties of the Zn(II) complex were presented comparatively.
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Affiliation(s)
- Necmi Dege
- Ondokuz Mayıs University, Faculty of Arts and Sciences, Department of Physics, 55139 Samsun, Turkey
| | - Özgen Özge
- Sakarya University, Faculty of Arts and Sciences, Department of Physics, 54187 Sakarya, Turkey
| | - Davut Avcı
- Sakarya University, Faculty of Arts and Sciences, Department of Physics, 54187 Sakarya, Turkey.
| | - Adil Başoğlu
- Sakarya University, Faculty of Arts and Sciences, Department of Physics, 54187 Sakarya, Turkey.
| | - Fatih Sönmez
- Sakarya University of Applied Sciences, Pamukova Vocational High School, 54055 Sakarya, Turkey
| | - Mavişe Yaman
- Ondokuz Mayıs University, Faculty of Arts and Sciences, Department of Physics, 55139 Samsun, Turkey
| | - Ömer Tamer
- Sakarya University, Faculty of Arts and Sciences, Department of Physics, 54187 Sakarya, Turkey
| | - Yusuf Atalay
- Sakarya University, Faculty of Arts and Sciences, Department of Physics, 54187 Sakarya, Turkey
| | - Belma Zengin Kurt
- Bezmialem Vakif University, Faculty of Pharmacy, Department of Pharmaceutical Chemistry, 34093 Istanbul, Turkey
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3
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Azad T, Torres HF, Auad ML, Elder T, Adamczyk AJ. Isolating key reaction energetics and thermodynamic properties during hardwood model lignin pyrolysis. Phys Chem Chem Phys 2021; 23:20919-20935. [PMID: 34541592 DOI: 10.1039/d1cp02917g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Computational studies on the pyrolysis of lignin using electronic structure methods have been largely limited to dimeric or trimeric models. In the current work we have modeled a lignin oligomer consisting of 10 syringyl units linked through 9 β-O-4' bonds. A lignin model of this size is potentially more representative of the polymer in angiosperms; therefore, we used this representative model to examine the behavior of hardwood lignin during the initial steps of pyrolysis. Using this oligomer, the present work aims to determine if and how the reaction enthalpies of bond cleavage vary with positions within the chain. To accomplish this, we utilized a composite method using molecular mechanics based conformational sampling and quantum mechanically based density functional theory (DFT) calculations. Our key results show marked differences in bond dissociation enthalpies (BDE) with the position. In addition, we calculated standard thermodynamic properties, including enthalpy of formation, heat capacity, entropy, and Gibbs free energy for a wide range of temperatures from 25 K to 1000 K. The prediction of these thermodynamic properties and the reaction enthalpies will benefit further computational studies and cross-validation with pyrolysis experiments. Overall, the results demonstrate the utility of a better understanding of lignin pyrolysis for its effective valorization.
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Affiliation(s)
- Tanzina Azad
- Department of Chemical Engineering, Auburn University, Auburn, AL, USA.
| | - Hazl F Torres
- Department of Chemical Engineering, Auburn University, Auburn, AL, USA.
| | - Maria L Auad
- Department of Chemical Engineering, Auburn University, Auburn, AL, USA. .,Center for Polymer and Advanced Composites, Auburn, AL, USA
| | - Thomas Elder
- United States Department of Agriculture (USDA) Forest Service, Southern Research Station, Auburn, AL, USA
| | - Andrew J Adamczyk
- Department of Chemical Engineering, Auburn University, Auburn, AL, USA.
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4
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Blaško M, Pašteka LF, Urban M. DFT Functionals for Modeling of Polyethylene Chains Cross-Linked by Metal Atoms. DLPNO-CCSD(T) Benchmark Calculations. J Phys Chem A 2021; 125:7382-7395. [PMID: 34428051 DOI: 10.1021/acs.jpca.1c04793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density functional theory (DFT) functionals for calculations of binding energies (BEs) of the polyethylene (PE) chains cross-linked by selected metal atoms (M) are benchmarked against DLPNO-CCSD(T) and DLPNO-CCSD(T1) data. PEX-M-PEX complexes as compared with plain parallel PEX···PEX chains with X = 3-9 carbon atoms are model species characterized by a cooperative effect of covalent C-M-C bonds and interchain dispersion interactions. The accuracy of DLPNO-CC methods was assessed by a comparison of BEs with the canonical CCSD(T) results for small PE3-M-PE3 complexes. Functionals for PEX···PEX and closed-shell PEX-M-PEX complexes (M = Be, Mg, Zn) were benchmarked against DLPNO-CCSD(T) BEs; open-shell complexes (M = Li, Ag, Au) were benchmarked against the DLPNO-CCSD(T1) method with iterative triples. Three dispersion corrections were combined with 25 DFT functionals for calculations of BEs with respect to PEX-M and PEX fragments employing def2-TZVPP and def2-QZVPP basis sets. Accuracy to within 5% for the closed-shell PEX-M-PEX complexes was achieved with five functionals. Less accurate are functionals for the open-shell PEX-M-PEX complexes; only two functionals deviate by less than 15% from DLPNO-CCSD(T1). Particularly problematic were PEX-Li-PEX complexes. A reasonable overall performance across all complexes in terms of the mean absolute percentage error is found for the range-separated hybrid functionals ωB97X-D3 and CAM-B3LYP/D3(BJ)-ABC.
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Affiliation(s)
- Martin Blaško
- FunGlass, A. Dubček University of Trenčín, Študentská 2, 911 50 Trenčín, Slovakia
| | - Lukáš F Pašteka
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Miroslav Urban
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
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5
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Zhou S, Jin K, Buehler MJ. Understanding Plant Biomass via Computational Modeling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2003206. [PMID: 32945027 DOI: 10.1002/adma.202003206] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Plant biomass, especially wood, has been used for structural materials since ancient times. It is also showing great potential for new structural materials and it is the major feedstock for the emerging biorefineries for building a sustainable society. The plant cell wall is a hierarchical matrix of mainly cellulose, hemicellulose, and lignin. Herein, the structure, properties, and reactions of cellulose, lignin, and wood cell walls, studied using density functional theory (DFT) and molecular dynamics (MD), which are the widely used computational modeling approaches, are reviewed. Computational modeling, which has played a crucial role in understanding the structure and properties of plant biomass and its nanomaterials, may serve a leading role on developing new hierarchical materials from biomass in the future.
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Affiliation(s)
- Shengfei Zhou
- Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Mass. Ave 1-290, Cambridge, MA, 02139, USA
| | - Kai Jin
- Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Mass. Ave 1-290, Cambridge, MA, 02139, USA
| | - Markus J Buehler
- Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Mass. Ave 1-290, Cambridge, MA, 02139, USA
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6
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De Santi A, Monti S, Barcaro G, Zhang Z, Barta K, Deuss PJ. New Mechanistic Insights into the Lignin β-O-4 Linkage Acidolysis with Ethylene Glycol Stabilization Aided by Multilevel Computational Chemistry. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2021; 9:2388-2399. [PMID: 33585085 PMCID: PMC7874265 DOI: 10.1021/acssuschemeng.0c08901] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/08/2021] [Indexed: 06/01/2023]
Abstract
Acidolysis in conjunction with stabilization of reactive intermediates has emerged as one of the most powerful methods of lignin depolymerization that leads to high aromatic monomer yields. In particular, stabilization of reactive aldehydes using ethylene glycol results in the selective formation of the corresponding cyclic acetals (1,3-dioxolane derivatives) from model compounds, lignin, and even from softwood lignocellulose. Given the high practical utility of this method for future biorefineries, a deeper understanding of the method is desired. Here, we aim to elucidate key mechanistic questions utilizing a combination of experimental and multilevel computational approaches. The multiscale computational protocol used, based on ReaxFF molecular dynamics, represents a realistic scenario, where a typical experimental setup can be reproduced confidently given the explicit molecules of the solute, catalyst, and reagent. The nudged elastic band (NEB) approach allowed us to characterize the key intermolecular interactions involved in the reaction paths leading to crucial intermediates and products. The high level of detail obtained clearly revealed for the first time the unique role of sulfuric acid as a proton donor and acceptor in lignin β-O-4 acidolysis as well as the reaction pathways for ethylene glycol stabilization, and the difference in reactivity between compounds with different methoxy substituents.
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Affiliation(s)
- Alessandra De Santi
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Department
of Chemical Engineering (ENTEG), University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Susanna Monti
- CNR-ICCOM−
Institute of Chemistry of Organometallic Compounds, via Moruzzi 1, 56124 Pisa, Italy
| | - Giovanni Barcaro
- CNR-IPCF−Institute
for Chemical and Physical Processes, via Moruzzi 1, 56124 Pisa, Italy
| | - Zhenlei Zhang
- Department
of Chemical Engineering (ENTEG), University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Katalin Barta
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Department
of Chemistry, Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse 28/II, 8010 Graz, Austria
| | - Peter J. Deuss
- Department
of Chemical Engineering (ENTEG), University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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7
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Roberts J, Song Y, Crocker M, Risko C. A Genetic Algorithmic Approach to Determine the Structure of Li-Al Layered Double Hydroxides. J Chem Inf Model 2020; 60:4845-4855. [PMID: 32794767 DOI: 10.1021/acs.jcim.0c00493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Layered double hydroxides (LDH) demonstrate significant potential across a range of applications, including as catalysts, delivery vehicles for pharmaceuticals, environmental remediation, and supercapacitors. Explaining the mechanism of LDH action at the atomic scale in these and other applications is challenging, however, due to the difficulty in precisely defining the bulk and surface structure and chemical compositions. Here, we focus on the determination of the structure of lithium-aluminum (Li-Al) LDH, which has shown promise in the catalytic depolymerization of lignin, both directly as the catalyst and as a support for gold nanoparticles. While the relative positions of the Li and Al metals are generally well resolved by X-ray crystallography, it is the structures of the anionic layers, consisting of water and carbonate, that are less well established. Combinatorial analyses of all possible positions and rotations of the water and carbonate in the three-layered Li-AL LDH polytope reveals that the phase space is much too large to examine in any reasonable time frame in a one-by-one structure exploration. To overcome this limitation, we develop and deploy a genetic algorithm (GA) wherein fitness is determined by matching a calculated X-ray diffraction (XRD) pattern for a given structure to the known experimental XRD pattern. The GA approach results in structures of high fitness that portend the bulk Li-Al LDH structure. Importantly, the GA approach offers the potential to determine the structures of other LDH, and more generally layered materials, which are generally difficult to describe given the large chemical and structural space to be explored.
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Affiliation(s)
- Josiah Roberts
- Department of Chemistry and Center for Applied Energy Research (CAER), University of Kentucky, Lexington, Kentucky 40506, United States
| | - Yang Song
- Department of Chemistry and Center for Applied Energy Research (CAER), University of Kentucky, Lexington, Kentucky 40506, United States
| | - Mark Crocker
- Department of Chemistry and Center for Applied Energy Research (CAER), University of Kentucky, Lexington, Kentucky 40506, United States
| | - Chad Risko
- Department of Chemistry and Center for Applied Energy Research (CAER), University of Kentucky, Lexington, Kentucky 40506, United States
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8
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Sikorska C, Gaston N. Modified Lennard-Jones potentials for nanoscale atoms. J Comput Chem 2020; 41:1985-2000. [PMID: 32592415 DOI: 10.1002/jcc.26368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/29/2020] [Accepted: 05/31/2020] [Indexed: 01/05/2023]
Abstract
A classical 6-12 Lennard-Jones (LJ) equation has been widely used to model materials and is the potential of choice in studies when the focus is on fundamental issues. Here we report a systematic study comparing the pair interaction potentials within solid-state materials (i.e., [Co6 Se8 (PEt3 )6 ][C60 ]2 , [Cr6 Te8 (PEt3 )6 ][C60 ]2 , [Ni9 Te6 (PEt3 )8 ][C60 ]) using density functional theory (DFT) calculations and LJ parametrization. Both classical (6-12 LJ) and modified LJ (mLJ) models were developed. In the mLJ approach, the exponents 6 and 12 are replaced by different integer number n and 2n, respectively, and an additional parameter (α) is introduced to describe intermolecular distance shift arising within the geometric centers' approach (instead of the shortest interatomic distance between particles). A general LJ approach reexamination reveals that in the case of nanoatoms, the attractive term decays with distance as the inverse fourth power, and the dominating at short distances repulsive term decays as the inverse eighth power. The modification of the LJ equation is even more prominent for interaction profiles, where intermolecular distance corresponds to separation between geometric centers of particles. In this approach, the attractive term decays with distance as the inverse 12th power, while the repulsive term decays rapidly (as the inverse 24th power). Thus, the mLJ models (e.g., 4-8 LJ) rather than the 6-12 classical ones seem to be a better choice for the description of binary interactions of nanoatoms. The developed mLJ models and electronic structure characteristics give an insight into the explanation of the unique physicochemical properties of superatomic-based solid-state materials.
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Affiliation(s)
- Celina Sikorska
- Department of Physics, The MacDiarmid Institute for Advanced Materials and Nanotechnology, The University of Auckland, Auckland, New Zealand
| | - Nicola Gaston
- Department of Physics, The MacDiarmid Institute for Advanced Materials and Nanotechnology, The University of Auckland, Auckland, New Zealand
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9
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Patel P, Wang J, Wilson AK. Prediction of pK a s of Late Transition-Metal Hydrides via a QM/QM Approach. J Comput Chem 2020; 41:171-183. [PMID: 31495951 DOI: 10.1002/jcc.26057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/04/2019] [Indexed: 11/09/2022]
Abstract
Three implicit solvation models, the conductor-like polarizable continuum model (C-PCM), the conductor-like screening model (COSMO), and universal implicit solvent model (SMD), combined with a hybrid two layer QM/QM approach (ONIOM), were utilized to calculate the pKa values, using a direct thermodynamic scheme, of a set of Group 10 transition metal (TM) hydrides in acetonitrile. To obtain the optimal combination of quantum methods for ONIOM calculations with implicit solvation models, the influence of factors, such as the choice of density functional and basis set, the atomic radii used to build a cavity in the solvent, and the size of the model system in an ONIOM scheme, was examined. Additionally, the impact of Grimme's empirical dispersion correction and exact exchange was also investigated. The results were calibrated by experimental data. This investigation provides insight about effective models for the prediction of thermodynamic properties of TM-containing complexes with bulky ligands. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Prajay Patel
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas, Denton, Texas, 76203-5017.,Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824-1322
| | - Jiaqi Wang
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas, Denton, Texas, 76203-5017.,Department of Chemistry, Beijing Forestry University, Beijing, China, 100083
| | - Angela K Wilson
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas, Denton, Texas, 76203-5017.,Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824-1322
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10
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Xia W, Xu T, Wang H. Thermal behaviors and harmful volatile constituents released from asphalt components at high temperature. JOURNAL OF HAZARDOUS MATERIALS 2019; 373:741-752. [PMID: 30959288 DOI: 10.1016/j.jhazmat.2019.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/19/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
Asphalt binder releases lots of heat and harmful volatiles at high temperature. To further understand thermal behaviors, dynamic release and toxic constituents of emitted volatiles during the combustion of asphalt binder, such fractions as saturates, aromatics, resins and asphaltenes (SARA) were first prepared. Thermal behaviors, volatile constituents and combustion residue microstructures of SARA fractions are discussed. Results indicate that polymerization degree of asphalt binder is high and the content of polycyclic aromatic compounds is large. Combustion processes of resins and asphaltenes only show single-stage exothermic reactions, but other two fractions present obvious multi-stage combustion reactions. As the heating rate is raised, the incomplete combustion of SARA fractions is increased, and more volatiles are released. Main volatiles released from SARA fractions are inflammable, toxic, corrosive or explosive compounds, and such common volatiles as acetaldehyde and propane are released from each SARA fraction. More toxic volatiles are released at combustion stage I, but macromolecular volatiles are mainly released at stage II. Volatile release behaviors of saturates and aromatics are more obviously affected by the heating rate. Combustion residues show more intact morphologies from saturates to asphaltenes, and mainly contain C, O and S elements. Asphalt binder is hazardous material at high temperature.
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Affiliation(s)
- Wenjing Xia
- College of Civil Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, Jiangsu, China
| | - Tao Xu
- College of Civil Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, Jiangsu, China.
| | - Hao Wang
- Department of Civil & Environmental Engineering, The State University of New Jersey, 96 Frelinghuysen Road, Piscataway, NJ 08854, United States
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11
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Wiles TC, Manby FR. Wavefunction-like Correlation Model for Use in Hybrid Density Functionals. J Chem Theory Comput 2018; 14:4590-4599. [PMID: 30080967 DOI: 10.1021/acs.jctc.8b00337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present Unsöld-W12 (UW12), an approximation to the correlation energy of molecules that is an explicit functional of the single-particle reduced-density matrix. The approximation resembles one part of modern explicitly correlated second-order Møller-Plesset (MP2) theory and is intended as an alternative to MP2 in double-hybrid exchange-correlation functionals. Orbital optimization with UW12 is straightforward, and the UW12 energy is evaluated without a double summation over unoccupied orbitals, leading to a faster basis-set convergence than is seen in double-hybrid functionals. We suggest a one-parameter hybrid exchange-correlation functional XCH-BLYP-UW12. XCH-BLYP-UW12 is similar to double-hybrid functionals, but contains UW12 correlation instead of MP2 correlation. We find that XCH-BLYP-UW12 is more accurate than the existing double-hybrid functional B2-PLYP for small-molecule main-group reaction barrier heights and has roughly the same accuracy as the existing hybrid functional B3LYP for atomization energies.
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Affiliation(s)
- Timothy C Wiles
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Frederick R Manby
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
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12
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Kwon DH, Proctor M, Mendoza S, Uyeda C, Ess DH. Catalytic Dinuclear Nickel Spin Crossover Mechanism and Selectivity for Alkyne Cyclotrimerization. ACS Catal 2017. [DOI: 10.1021/acscatal.7b00978] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Doo-Hyun Kwon
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Matthew Proctor
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Sergio Mendoza
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Christopher Uyeda
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Daniel H. Ess
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
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13
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Asatryan R, Bennadji H, Bozzelli JW, Ruckenstein E, Khachatryan L. Molecular Products and Fundamentally Based Reaction Pathways in the Gas-Phase Pyrolysis of the Lignin Model Compound p-Coumaryl Alcohol. J Phys Chem A 2017; 121:3352-3371. [PMID: 28406634 DOI: 10.1021/acs.jpca.7b01656] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The fractional pyrolysis of lignin model compound para-coumaryl alcohol (p-CMA) containing a propanoid side chain and a phenolic OH group was studied using the System for Thermal Diagnostic Studies at temperatures from 200 to 900 °C, in order to gain mechanistic insight into the role of large substituents in high-lignin feedstocks pyrolysis. Phenol and its simple derivatives p-cresol, ethyl-, propenyl-, and propyl-phenols were found to be the major products predominantly formed at low pyrolysis temperatures (<500 °C). A cryogenic trapping technique was employed combined with EPR spectroscopy to identify the open-shell intermediates registered at pyrolysis temperatures above 500 °C. These were characterized as radical mixtures primarily consisting of oxygen-linked conjugated radicals. A comprehensive potential energy surface analysis of p-CMA and p-CMA + H atom systems was performed using various DFT protocols to examine the possible role of concerted molecular eliminations and free-radical mechanisms in the formation of major products. Other significant unimolecular concerted reactions along with formation and decomposition of primary radicals are also described and evaluated. The calculations suggest that a set of the chemically activated secondary radical channels is relevant to the low temperature product formation under fractional pyrolysis conditions.
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Affiliation(s)
- Rubik Asatryan
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York , Buffalo, New York 14226, United States
| | - Hayat Bennadji
- Department of Environmental Sciences, Louisiana State University , Baton Rouge, Louisiana 70808, United States
| | - Joseph W Bozzelli
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology , Newark, New Jersey 07102, United States
| | - Eli Ruckenstein
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York , Buffalo, New York 14226, United States
| | - Lavrent Khachatryan
- Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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15
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Dinda S, Chiu CC, Genest A, Rösch N. Evaluation of density functionals for elementary steps of selective oxidation reactions. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2016.12.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Ioannidis EI, Kulik HJ. Ligand-Field-Dependent Behavior of Meta-GGA Exchange in Transition-Metal Complex Spin-State Ordering. J Phys Chem A 2017; 121:874-884. [DOI: 10.1021/acs.jpca.6b11930] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Efthymios I. Ioannidis
- Department
of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department
of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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17
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Minenkov Y, Sliznev VV, Cavallo L. Accurate Gas Phase Formation Enthalpies of Alloys and Refractories Decomposition Products. Inorg Chem 2017; 56:1386-1401. [DOI: 10.1021/acs.inorgchem.6b02441] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yury Minenkov
- Physical Sciences
and Engineering Division, King Abdullah University of Science and Technology, KAUST Catalysis Center, Thuwal 23955-6900, Saudi Arabia
| | - Valery V. Sliznev
- Ivanovo State University of Chemistry and Technology, Research Institute for Thermodynamics
and Kinetics of Chemical Processes, 153460 Ivanovo, Russian Federation
| | - Luigi Cavallo
- Physical Sciences
and Engineering Division, King Abdullah University of Science and Technology, KAUST Catalysis Center, Thuwal 23955-6900, Saudi Arabia
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18
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Mar BD, Kulik HJ. Depolymerization Pathways for Branching Lignin Spirodienone Units Revealed with ab Initio Steered Molecular Dynamics. J Phys Chem A 2017; 121:532-543. [PMID: 28005362 DOI: 10.1021/acs.jpca.6b11414] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lignocellulosic biomass is an abundant, rich source of aromatic compounds, but direct utilization of raw lignin has been hampered by both the high heterogeneity and variability of linking bonds in this biopolymer. Ab initio steered molecular dynamics (AISMD) has emerged both as a fruitful direct computational screening approach to identify products that occur through mechanical depolymerization (i.e., in sonication or ball-milling) and as a sampling approach. By varying the direction of force and sampling over 750 AISMD trajectories, we identify numerous possible pathways through which lignin depolymerization may occur in pyrolysis or through catalytic depolymerization as well. Here, we present eight unique major depolymerization pathways discovered via AISMD for the recently characterized spirodienone lignin branching linkage that may comprise around 10% weight of all lignin in some softwoods. We extract representative trajectories from AISMD and carry out reaction pathway analysis to identify energetically favorable pathways for lignin depolymerization. Importantly, we identify dynamical effects that could not be observed through more traditional calculations of bond dissociation energies. Such effects include thermodynamically favorable recovery of aromaticity in the dienone ring that leads to near-barrierless subsequent ether cleavage and hydrogen-bonding effects that stabilize newly formed radicals. Some of the most stable spirodienone fragments that reside at most 1 eV above the reactant structure are formed with only 2 eV barriers for C-C bond cleavage, suggesting key targets for catalyst design to drive targeted depolymerization of lignin.
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Affiliation(s)
- Brendan D Mar
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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19
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Goerigk L, Hansen A, Bauer C, Ehrlich S, Najibi A, Grimme S. A look at the density functional theory zoo with the advanced GMTKN55 database for general main group thermochemistry, kinetics and noncovalent interactions. Phys Chem Chem Phys 2017; 19:32184-32215. [DOI: 10.1039/c7cp04913g] [Citation(s) in RCA: 854] [Impact Index Per Article: 122.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We present the updated and extended GMTKN55 benchmark database for more accurate and extensive energetic evaluation of density functionals and other electronic structure methods with detailed guidelines for method users.
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Affiliation(s)
- Lars Goerigk
- School of Chemistry
- The University of Melbourne
- Parkville
- Australia
| | - Andreas Hansen
- Universität Bonn
- Mulliken Center for Theoretical Chemistry
- Bonn
- Germany
| | - Christoph Bauer
- Universität Bonn
- Mulliken Center for Theoretical Chemistry
- Bonn
- Germany
| | - Stephan Ehrlich
- Universität Bonn
- Mulliken Center for Theoretical Chemistry
- Bonn
- Germany
| | - Asim Najibi
- School of Chemistry
- The University of Melbourne
- Parkville
- Australia
| | - Stefan Grimme
- Universität Bonn
- Mulliken Center for Theoretical Chemistry
- Bonn
- Germany
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