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Akhlaghi Bagherjeri M, Monhemi H, Haque ANMA, Naebe M. Molecular mechanism of cellulose dissolution in N-methyl morpholine-N-oxide: A molecular dynamics simulation study. Carbohydr Polym 2024; 323:121433. [PMID: 37940258 DOI: 10.1016/j.carbpol.2023.121433] [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: 07/21/2023] [Revised: 09/19/2023] [Accepted: 09/24/2023] [Indexed: 11/10/2023]
Abstract
N-methyl morpholine-N-oxide (NMMO) is the only commercialised solvent to dissolve cellulose and produce lyocell. However, the molecular mechanism of NMMO-induced cellulose solubilisation is unknown which limits further process development. In this work, and for the first time the complete dissolution process of a large cellulose bunch was simulated in NMMO monohydrate using long microsecond molecular dynamic simulations. The dissolution process was also simulated in 1-ethyl-3-methylimidazolium acetate (EmimAc) as an efficient ionic liquid in cellulose dissolution and the results were compared with the aqueous conditions. While the cellulose bunch showed a stable and insoluble structure in pure water, it was completely and efficiently dissolved in both NMMO monohydrate and EmimAc. It was shown that the dissolution time of cellulose in NMMO monohydrate is almost twice that in EmimAc, which is in agreement with the experimental observations. Although it is revealed that hydrogen bonding is the main driving force of cellulose dissolution in NMMO monohydrate, one cannot explain the complete molecular mechanism of NMMO-induced cellulose dissolution only by considering hydrogen bonds. A straightforward molecular mechanism was proposed, in which the interactions of NMMO molecules, not with cellulose, but with the other NMMO molecules play a critical role in the dissolution process.
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Affiliation(s)
| | - Hassan Monhemi
- Department of Chemistry, University of Neyshabur, Neyshabur, Iran
| | | | - Maryam Naebe
- Deakin University, Institute for Frontier Materials, Geelong, Victoria 3216, Australia.
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2
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Schutt TC, Shukla MK. Computational Investigation on Interactions between Some Munition Compounds and Humic Substances. J Phys Chem A 2020; 124:10799-10807. [PMID: 33315403 DOI: 10.1021/acs.jpca.0c08177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Humic acid substances (HAs) in natural soil and sediment environments affect the retention and degradation of insensitive munition compounds and legacy high explosives (MCs): 2,4-dinitroanisole (DNAN), DNi-NH4+, N-methyl-p-nitroaniline (nMNA), 1-nitroguanidine (NQ), 3-nitro-1,2,4-triazol-5-one (NTO; neutral and anionic forms), 2,4,6-trinitrotoluene (TNT), and 1,3,5-trinitro-1,3,5-triazinane (RDX). A humic acid model compound has been considered using molecular dynamics, thermodynamic integration, and density functional theory to characterize the munition binding ability, ionization potential, and electron affinity compared to that in the water solution. Humic acids bind most compounds and act as both a sink and source for electrons. Ionization potentials suggest that HAs are more susceptible to oxidation than the MCs studied. The electron affinity of HAs is very conformation-dependent and spans the same range as the munition compounds. When HAs and MCs are complexed, the HAs tend to radicalize first, thus buffering MCs against reductive as well as oxidative attacks.
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Affiliation(s)
- Timothy C Schutt
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, Mississippi 39180, United States
| | - Manoj K Shukla
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, Mississippi 39180, United States
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Schutt TC, Shukla MK. Predicting the Impact of Aqueous Ions on Fate and Transport of Munition Compounds in the Environment. J Phys Chem A 2019; 123:4973-4979. [PMID: 31070365 DOI: 10.1021/acs.jpca.9b01742] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A model framework for natural water has been developed using computational chemistry techniques to elucidate the interactions between solvated munition compounds and eight common ions in naturally occurring water sources. The interaction energies, residence times, coordination statistics, and surface preferences of nine munition-related compounds with each ion were evaluated. The propensity of these interactions to increase degradation of the munition compound was predicted using accelerated replica QM/MM simulations. The degradation prediction data qualitatively align with previous quantum mechanical studies. The results suggest that primary ions of interest for fate and transport modeling of munition compounds in natural waters may follow the relative importance of SO42-, Cl- ≫ HCO3-, Na+, Mg2+ > Ca2+, K+, and NH4+.
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Affiliation(s)
- Timothy C Schutt
- U.S. Army Engineer Research and Development Center , Environmental Laboratory , 3909 Halls Ferry Road , Vicksburg , Mississippi 39180 , United States
| | - Manoj K Shukla
- U.S. Army Engineer Research and Development Center , Environmental Laboratory , 3909 Halls Ferry Road , Vicksburg , Mississippi 39180 , United States
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Hikiri S, Hayashi T, Ikeguchi M, Kinoshita M. Statistical thermodynamics for the unexpectedly large difference between disaccharide stereoisomers in terms of solubility in water. Phys Chem Chem Phys 2018; 20:23684-23693. [PMID: 30191211 DOI: 10.1039/c8cp04377a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We unravel the physical origins of the large difference between cellobiose and maltose, which consist of two β-1,4 and α-1,4 linked d-glucose units, respectively, in terms of the solubility in water. We construct a thermodynamic theory where the chemical-potential difference between disaccharides in water and in vacuum is identified as the key free-energy function. Its energetic and entropic components are calculated for cellobiose and maltose by statistical-mechanical theories for solute hydration. The disaccharide structures are taken into account at the atomic level and a molecular model is adopted for water. Molecular dynamics simulations are used to account for the conformational fluctuation of a disaccharide molecule, which also enables us to estimate the conformational entropy. We show that the cellobiose/maltose solubility ratio calculated is in good agreement with the experimental value. The solubility becomes much lower for cellobiose due to conformational-entropy and water-entropy effects. The former effect is relevant to higher stability of the intramolecular hydrogen bond between oxygen atoms in the six-membered ring and in the neighboring hydroxyl group: the hydration alters the fluctuation of a molecular conformation to a larger or less regular one, but the degree of this alteration is smaller. The latter effect is attributed to more separation of two hydroxymethyl groups in a molecule, causing lower probability of the overlap of excluded volumes generated by the groups for water molecules. We suggest that physicochemical properties of disaccharides in water become variable depending on the stereoisomerism through hydration effects and the origins of the variety are entropic.
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Affiliation(s)
- Simon Hikiri
- Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
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Ries ME, Radhi A, Green SM, Moffat J, Budtova T. Microscopic and Macroscopic Properties of Carbohydrate Solutions in the Ionic Liquid 1-Ethyl-3-methyl-imidazolium Acetate. J Phys Chem B 2018; 122:8763-8771. [DOI: 10.1021/acs.jpcb.8b06939] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael E. Ries
- Soft Matter Physics Research Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT. U.K
| | - Asanah Radhi
- Soft Matter Physics Research Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT. U.K
| | - Stephen M. Green
- Soft Matter Physics Research Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT. U.K
| | - Jamie Moffat
- Innovia Films R&D Centre, West Road, Wigton, Cumbria CA7 9XX, U.K
| | - Tatiana Budtova
- MINES ParisTech, PSL Research University, Center for Materials Forming (CEMEF), UMR CNRS 7635, CS 10207, 06904 Sophia Antipolis, France
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Effects of C(2) Methylation on Thermal Behavior and Interionic Interactions in Imidazolium-Based Ionic Liquids with Highly Symmetric Anions. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8071043] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Li Y, Wang J, Liu X, Zhang S. Towards a molecular understanding of cellulose dissolution in ionic liquids: anion/cation effect, synergistic mechanism and physicochemical aspects. Chem Sci 2018; 9:4027-4043. [PMID: 29780532 PMCID: PMC5941279 DOI: 10.1039/c7sc05392d] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/25/2018] [Indexed: 12/23/2022] Open
Abstract
Cellulose is one of the most abundant bio-renewable materials on the earth and its conversion to biofuels provides an appealing way to satisfy the increasing global energy demand. However, before carrying out the process of enzymolysis to glucose or polysaccharides, cellulose needs to be pretreated to overcome its recalcitrance. In recent years, a variety of ionic liquids (ILs) have been found to be effective solvents for cellulose, providing a new, feasible pretreatment strategy. A lot of experimental and computational studies have been carried out to investigate the dissolution mechanism. However, many details are not fully understood, which highlights the necessity to overview the current knowledge of cellulose dissolution and identify the research trend in the future. This perspective summarizes the mechanistic studies and microscopic insights of cellulose dissolution in ILs. Recent investigations of the synergistic effect of cations/anions and the distinctive structural changes of cellulose microfibril in ILs are also reviewed. Besides, understanding the factors controlling the dissolution process, such as the structure of anions/cations, viscosity of ILs, pretreatment temperature, heating rate, etc., has been discussed from a structural and physicochemical viewpoint. At the end, the existing problems are discussed and future prospects are given. We hope this article would be helpful for deeper understanding of the cellulose dissolution process in ILs and the rational design of more efficient and recyclable ILs.
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Affiliation(s)
- Yao Li
- Beijing Key Laboratory of Ionic Liquids Clean Process , CAS Key Laboratory of Green Process and Engineering , Institute of Process Engineering , Chinese Academy of Sciences , Beijing , 100190 , P. R. China . ;
| | - Jianji Wang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals , School of Chemistry and Chemical Engineering , Key Laboratory of Green Chemical Media and Reactions , Henan Normal University , Xinxiang , Henan 453007 , P. R. China
| | - Xiaomin Liu
- Beijing Key Laboratory of Ionic Liquids Clean Process , CAS Key Laboratory of Green Process and Engineering , Institute of Process Engineering , Chinese Academy of Sciences , Beijing , 100190 , P. R. China . ;
| | - Suojiang Zhang
- Beijing Key Laboratory of Ionic Liquids Clean Process , CAS Key Laboratory of Green Process and Engineering , Institute of Process Engineering , Chinese Academy of Sciences , Beijing , 100190 , P. R. China . ;
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8
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Solvation free energy of solvation of biomass model cellobiose molecule: A molecular dynamics analysis. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.06.083] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Schutt TC, Hegde GA, Bharadwaj VS, Johns AJ, Maupin CM. Impact of Water-Dilution on the Solvation Properties of the Ionic Liquid 1-Methyltriethoxy-3-ethylimidazolium Acetate for Model Biomass Molecules. J Phys Chem B 2017; 121:843-853. [DOI: 10.1021/acs.jpcb.6b09101] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Timothy C. Schutt
- Chemical and Biological Engineering
Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Govind A. Hegde
- Chemical and Biological Engineering
Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Vivek S. Bharadwaj
- Chemical and Biological Engineering
Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Adam J. Johns
- Chemical and Biological Engineering
Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - C. Mark Maupin
- Chemical and Biological Engineering
Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
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Hegde GA, Bharadwaj VS, Kinsinger CL, Schutt TC, Pisierra NR, Maupin CM. Impact of water dilution and cation tail length on ionic liquid characteristics: Interplay between polar and non-polar interactions. J Chem Phys 2016. [DOI: 10.1063/1.4960511] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Govind A. Hegde
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
| | - Vivek S. Bharadwaj
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
| | - Corey L. Kinsinger
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
| | - Timothy C. Schutt
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
| | - Nichole R. Pisierra
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
| | - C. Mark Maupin
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
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Schutt TC, Bharadwaj VS, Hegde GA, Johns AJ, Mark Maupin C. In silico insights into the solvation characteristics of the ionic liquid 1-methyltriethoxy-3-ethylimidazolium acetate for cellulosic biomass. Phys Chem Chem Phys 2016; 18:23715-26. [PMID: 27510272 DOI: 10.1039/c6cp03235d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lignocellulosic biomass is a domestically grown, sustainable, and potentially carbon-neutral feedstock for the production of liquid fuels and other value added chemicals. This underutilized renewable feedstock has the potential to alleviate some of the current socio-economic dependence on foreign petroleum supplies while stimulating rural economies. Unfortunately, the potential of biomass has largely been underdeveloped due to the recalcitrant nature of lignocellulosic materials. Task-specific ionic liquids (ILs) have shown considerable promise as an alternative non-aqueous solvent for solvation and deconstruction of lignocellulose in the presence of metal chloride catalyst or enzymes. Recently it has been hypothesized that adding oxygen atoms to the tail of an imidazolium cation would alleviate some of the negative characteristics of the ILs by increasing mass transport properties, and decreasing IL deactivation of enzymes, while at the same time retaining favorable solvation characteristics for lignocellulose. Reported here are fully atomistic molecular dynamic simulations of 1-methyltriethoxy-3-ethylimidazolium acetate ([Me-(OEt)3-Et-IM(+)] [OAc(-)]) that elucidate promising molecular-level details pertaining to the solvation characteristics of model compounds of cellulose, and IL-induced side-chain and ring puckering conformations. It is found that the anion interactions with the saccharide induce alternate ring puckering conformations from those seen in aqueous environments (i.e.(1)C4), while the cation interactions are found to influence the conformation of the ω dihedral. These perturbations in saccharide structures are discussed in the context of their contribution to the disruption of hydrogen bonding in cellulosic architecture and their role in solvation.
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Affiliation(s)
- Timothy C Schutt
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401, USA.
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12
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Baker JL, Furbish J, Lindberg GE. Influence of the ionic liquid [C4mpy][Tf2N] on the structure of the miniprotein Trp-cage. J Mol Graph Model 2015; 62:202-212. [PMID: 26479192 DOI: 10.1016/j.jmgm.2015.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 09/14/2015] [Accepted: 10/06/2015] [Indexed: 10/22/2022]
Abstract
We examine the effect of the ionic liquid [C4mpy][Tf2N] on the structure of the miniprotein Trp-cage and contrast these results with the behavior of Trp-cage in water. We find the ionic liquid has a dramatic effect on Trp-cage, though many similarities with aqueous Trp-cage are observed. We assess Trp-cage folding by monitoring root mean square deviation from the crystallographic structure, radius of gyration, proline cis/trans isomerization state, protein secondary structure, amino acid contact formation and distance, and native and non-native contact formation. Starting from an unfolded configuration, Trp-cage folds in water at 298 K in less than 500 ns of simulation, but has very little mobility in the ionic liquid at the same temperature, which can be ascribed to the higher ionic liquid viscosity. At 365 K, the mobility of the ionic liquid is increased and initial stages of Trp-cage folding are observed, however Trp-cage does not reach the native folded state in 2 μs of simulation in the ionic liquid. Therefore, in addition to conventional molecular dynamics, we also employ scaled molecular dynamics to expedite sampling, and we demonstrate that Trp-cage in the ionic liquid does closely approach the aqueous folded state. Interestingly, while the reduced mobility of the ionic liquid is found to restrict Trp-cage motion, the ionic liquid does facilitate proline cis/trans isomerization events that are not seen in our aqueous simulations.
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Affiliation(s)
- Joseph L Baker
- Department of Chemistry, The College of New Jersey, 2000 Pennington Road, Ewing, NJ 08628, United States.
| | - Jeffrey Furbish
- Department of Chemistry, The College of New Jersey, 2000 Pennington Road, Ewing, NJ 08628, United States
| | - Gerrick E Lindberg
- Department of Chemistry and Biochemistry, Northern Arizona University, 700 S. Osbourne Drive, Flagstaff, AZ 86011, United States.
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Schutt TC, Bharadwaj VS, Granum DM, Maupin CM. The impact of active site protonation on substrate ring conformation in Melanocarpus albomyces cellobiohydrolase Cel7B. Phys Chem Chem Phys 2015; 17:16947-58. [DOI: 10.1039/c5cp01801c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding how the protonation state of active site residues impacts the enzyme's structure and substrate conformation is important for improving the efficiency and economic viability of the degradation of cellulosic materials as feedstock for liquid fuel and value-added chemicals.
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Affiliation(s)
- Timothy C. Schutt
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
| | - Vivek S. Bharadwaj
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
| | - David M. Granum
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
| | - C. Mark Maupin
- Chemical and Biological Engineering Department
- Colorado School of Mines
- Golden
- USA
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