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Steele BA, Zhang MX, Kuo IFW. Single-Step Mechanism for Regioselective Nitration of 9,10-BN-Napthalene with Acetyl Nitrate in the Gas Phase. J Phys Chem A 2022; 126:5089-5098. [PMID: 35916696 DOI: 10.1021/acs.jpca.2c02124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The energetics of the regioselective mononitration of 9,10-BN-naphthalene with acetyl nitrate (H3C2NO4) were modeled with ab initio simulations in the gas phase and an acetonitrile solvent. The single-electron-transfer (SET) nitration mechanism leading to a σ-complex and a single-step nitration mechanism were modeled. The energy barrier for the single-step mechanism was lower than that for the SET mechanism in the gas phase. However, the two are much more energetically competitive in the solvent. The σ-complex was found to be unstable in the gas phase owing to the interaction with the counterion. Using the single-step mechanism, the carbon site 1 nearest boron had the lowest activation energy for nitration of 22.6 kcal/mol, while site 3 had the second lowest barrier of 24.6 kcal/mol. Details on the molecular structures at intermediate and transition states as well as charges in different configurations are discussed.
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Affiliation(s)
- Brad A Steele
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, P. O. Box 808, Livermore, California 94550, United States
| | - Mao-Xi Zhang
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, P. O. Box 808, Livermore, California 94550, United States
| | - I-Feng W Kuo
- Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, P. O. Box 808, Livermore, California 94550, United States
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Maraf MB, Idrice AA, Mekoung Pélagie MA, Zintchem AAA, Bebga G, Rhyman L, Ibrahim MN, Ramasami P. Decoding the reaction mechanism of the cyclocondensation of ethyl acetate2-oxo-2-(4-oxo-4H-pyrido [1.2-a] pyrimidin-3-yl) polyazaheterocycle and ethylenediamine using bond evolution theory. J Comput Chem 2022; 43:972-985. [PMID: 35383996 DOI: 10.1002/jcc.26853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/05/2022] [Accepted: 02/28/2022] [Indexed: 11/12/2022]
Abstract
We investigated the flow of electron density along the cyclocondensation reaction between ethyl acetate 2-oxo-2-(4-oxo-4H-pyrido[1.2-a]pyrimidin-3-yl) polyazaheterocycle (1) and ethylenediamine (2) at the ωB97XD/6-311++G(d,p)computational method within of bond evolution theory (BET). The exploration of potential energy surface shows that this reaction has three channels (1-3) with the formation of product 3 via channel-2 (the most favorable one) as the main product and this is in good agreement with experimental observations. The BET analysis allows identifying unambiguously the main chemical events happening along channel-2. The mechanism along first step (TS2-a) is described by a series of four structural stability domains (SSDs), while five SSDs for the last two steps (TS2-b and TS2-c). The first and third steps can be summarized as follows, the formation of N1-C6 bond (SSD-II), then, the restoration of the nitrogen N1 lone pair (SSD-III), and finally, the formation of the last O1-H1 bond (SSD-IV). For the second step, the formation of hydroxide ion is noted, as a result of the disappearance of V(C6,O7) basin and the transformation of C6-N1 single bond into double one (SSD-IV). Finally, the appearance of V(O7,H2) basin lead to the elimination of water molecule within the last domain is observed.
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Affiliation(s)
- Mbah Bake Maraf
- Physical and Theoretical Chemistry unit, Laboratory of applied Physical and Analytical Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.,Computational Chemistry Laboratory, Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - Adjieufack Abel Idrice
- Physical and Theoretical Chemistry unit, Laboratory of applied Physical and Analytical Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.,Computational Chemistry Laboratory, Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon.,Laboratory of Theoretical Chemistry (LCT) and Namur Institute of Structured Matter (NISM), University of Namur, Namur, Belgium
| | - Manwal A Mekoung Pélagie
- Physical and Theoretical Chemistry unit, Laboratory of applied Physical and Analytical Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.,Computational Chemistry Laboratory, Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - Auguste Abouem A Zintchem
- Computational Chemistry Laboratory, Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - Gouet Bebga
- Computational Chemistry Laboratory, Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - Lydia Rhyman
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, Mauritius.,Centre for Natural Product Research, Department of Chemical Sciences, University of Johannesburg, Doornfontein, South Africa
| | - Mbouombouo Ndassa Ibrahim
- Computational Chemistry Laboratory, Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon
| | - Ponnadurai Ramasami
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, Mauritius.,Centre for Natural Product Research, Department of Chemical Sciences, University of Johannesburg, Doornfontein, South Africa
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Adjieufack AI, Liégeois V, Mbouombouo Ndassa I, Champagne B. Topological investigation of the reaction mechanism of glycerol carbonate decomposition by bond evolution theory. RSC Adv 2021; 11:10083-10093. [PMID: 35423535 PMCID: PMC8695523 DOI: 10.1039/d0ra09755a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/26/2021] [Indexed: 11/30/2022] Open
Abstract
The reaction mechanisms of the decomposition of glycerol carbonate have been investigated at the density functional theory level within the bond evolution theory. The four reaction pathways yield to 3-hydroxypropanal (TS1), glycidol (TS2a and TS2b), and 4-methylene-1,3-dioxolan-2-one (TS3). The study reveals non-concerted processes with the same number (four) of structural stability domains for each reaction pathway. For the two decarboxylation mechanisms, the two first steps are similar. They correspond to the cleavage of two single CO bonds to the detriment of the increased population of the lone pairs of two O atoms. These are followed, along TS1, by the transformation of a CO single bond into a double bond together with a proton transfer to create a CH bond. For TS2a and TS2b, the last step is a cyclization by CO bond formation. For the TS3 pathway, the first stage consists in the cleavage of a CH bond and the transfer of its electron population to both a proton and a C atom, the second step corresponds to the formation of an OH bond, and the last one describes the formation of a CC double bond. Moreover, the analysis of the energies, enthalpies, and free enthalpies of reaction and of activation leads to the conclusion that 3-hydroxypropanal is both the thermodynamic and kinetic product, independent of the method of calculation. ELFs of glycerol carbonate and of its kinetic and thermodynamic decomposition product, 3-hydroxypropanal (+CO2).![]()
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Affiliation(s)
- Abel Idrice Adjieufack
- Physical and Theoretical Chemistry Laboratory
- Cameroon
- Computational Chemistry Laboratory
- High Teacher Training College
- Cameroon
| | - Vincent Liégeois
- Laboratory of Theoretical Chemistry and Namur Institute of Structured Matter (NISM)
- University of Namur
- B-5000 Namur
- Belgium
| | | | - Benoît Champagne
- Laboratory of Theoretical Chemistry and Namur Institute of Structured Matter (NISM)
- University of Namur
- B-5000 Namur
- Belgium
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Domingo LR, Ríos-Gutiérrez M, Aurell MJ. Unveiling the regioselectivity in electrophilic aromatic substitution reactions of deactivated benzenes through molecular electron density theory. NEW J CHEM 2021. [DOI: 10.1039/d1nj02435c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Regioselectivity results from the slight polarization of the electron density and weak repulsive interactions appearing along the ortho approach mode.
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Affiliation(s)
- Luis R. Domingo
- Department of Organic Chemistry
- University of Valencia, Dr Moliner 50
- Valencia
- Spain
| | - Mar Ríos-Gutiérrez
- Department of Organic Chemistry
- University of Valencia, Dr Moliner 50
- Valencia
- Spain
| | - María José Aurell
- Department of Organic Chemistry
- University of Valencia, Dr Moliner 50
- Valencia
- Spain
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Kyprianou D, Berglund M, Emma G, Rarata G, Anderson D, Diaconu G, Exarchou V. Synthesis of 2,4,6-Trinitrotoluene (TNT) Using Flow Chemistry. Molecules 2020; 25:E3586. [PMID: 32781765 PMCID: PMC7465666 DOI: 10.3390/molecules25163586] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/03/2020] [Accepted: 08/04/2020] [Indexed: 11/16/2022] Open
Abstract
This paper describes the nitration of 2,4-dinitrotoluene (DNT) and its conversion to 2,4,6-trinitrotoluene (TNT) at a gram scale with the use of a fully automated flow chemistry system. The conversion of DNT to TNT traditionally requires the use of highly hazardous reagents like fuming sulfuric acid (oleum), fuming nitric acid (90-100%), and elevated temperatures. Flow chemistry offers advantages compared to conventional syntheses including a high degree of safety and simpler multistep automation. The configuration and development of this automated process based on a commercially available flow chemistry system is described. A high conversion rate (>99%) was achieved. Unlike established synthetic methods, ordinary nitrating mixture (65% HNO3/98% H2SO4) and shorter reaction times (10-30 min) were applied. The viability of flow nitration as a means of safe and continuous synthesis of TNT was investigated. The method was optimized using an experimental design approach, and the resulting process is safer, faster, and more efficient than previously reported TNT synthesis procedures. We compared the flow chemistry and batch approaches, including a provisional cost calculation for laboratory-scale production (a thorough economic analysis is, however, beyond the scope of this article). The method is considered fit for purpose for the safe production of high-purity explosives standards at a gram scale, which are used to verify that the performance of explosive trace detection equipment complies with EU regulatory requirements.
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Affiliation(s)
| | | | | | | | - David Anderson
- Joint Research Centre, European Commission, Retieseweg 111, 2440 Geel, Belgium; (D.K.); (M.B.); (G.E.); (G.R.); (G.D.); (V.E.)
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