1
|
Mukeba CT, Isamura BK, Mudogo V, Katshiatshia HM, Muya JT. Bond dissociation energies of ethyl valerate and tripropionin. J Mol Model 2023; 29:261. [PMID: 37482544 DOI: 10.1007/s00894-023-05666-6] [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: 05/12/2023] [Accepted: 07/13/2023] [Indexed: 07/25/2023]
Abstract
CONTEXT Due to the expected decrease in the availability of conventional oils, numerous studies are currently underway to find complementary sources of energy. Among the explored avenue is that of biofuels. Ethyl valerate (ETV) and tripropionin (TPP) are two biofuels whose thermal decomposition has not received the attention it deserves. Herein, we have evaluated the bond dissociation enthalpies (BDHs) to predict how easy it is to break some bonds in these compounds, and subsequently contribute to revealing the initiation step in their combustion reactions. Our computations consistently predict C4-C5 and C1-C2 bonds in ETV and TPP as the weakest bonds, likely to break first and initiate the thermal decomposition of these two compounds, respectively. The conformational changes in ETV and TPP have only a small influence on the BDHs of 1 kcal/mol at M06-2X/6-311 + G(3df,2p). B3LYP and ωB97XD appear to be the most affordable methods for estimating BDHs at 6-31G(d,p) as they give good results for ETV (RMSD: 2.94 kcal/mol and 3.22 kcal/mol) and performed better than CBS-QB3 (RMSD: 3.64 kcal/mol). Using a larger basis set, the M06-2X (RMSD: 3.61 kcal/mol) and ωB97XD (RMSD: 3.51 kcal/mol) functionals are found to provide the most accurate predictions at 6-311 + G(3df,2p) as compared to G4MP2. METHODS BDHs of ETV and TPP are computed using density functional theory (DFT) and quantum chemistry composite methods at 6-31G(d,p) and 6-311 + G(3df,2p) levels. Because of its reliability and accuracy in thermochemical calculations, the G4MP2 theory is used as a reference to gauge the performance of DFT methods. All the calculations were carried out using the Gaussian 09 program.
Collapse
Affiliation(s)
- Christian Tshikala Mukeba
- Department of Chemistry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
- Research Center for Theoretical Chemistry and Physics in Central Africa, Faculty of Science, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Bienfait Kabuyaya Isamura
- Department of Chemistry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
- Research Center for Theoretical Chemistry and Physics in Central Africa, Faculty of Science, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
- Department of Chemistry, University of Manchester, M13 9PL, Manchester, Great Britain
| | - Virima Mudogo
- Department of Chemistry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
- Research Center for Applied Sciences and Technologies, Kinshasa, B.P. 8401, Democratic Republic of the Congo
| | - Haddy Mbuyi Katshiatshia
- Research Center for Renewable Energy, Polytechnics Faculty, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
| | - Jules Tshishimbi Muya
- Department of Chemistry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
- Research Center for Theoretical Chemistry and Physics in Central Africa, Faculty of Science, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
| |
Collapse
|
2
|
Liu J, Yang SW, Zhao W, Wu YL, Hu B, Hu SH, Ma SW, Lu Q. Theoretical study on the mechanism of sulfur migration to gas in the pyrolysis of benzothiophene. Front Chem Sci Eng 2022. [DOI: 10.1007/s11705-022-2209-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
3
|
Stimulation calculation of desulfurization mechanisms dominated by free radicals reactions during pyrolysis of thiophenes under water vapor atmosphere. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
4
|
Sehrawat M, Rani M, Dariyal P, Bharadwaj S, Dhakate SR, Singh BP. Highly conductive CNT aerogel synthesized via an inert FC-CVD technique: a step towards a greener approach. REACT CHEM ENG 2022. [DOI: 10.1039/d2re00170e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The accumulation of hydrogen gas molecules generated in situ as a byproduct of chemical reactions enhances the reducing ambient conditions of the otherwise inert FC-CVD reactor which improves the quality of the CNTs.
Collapse
Affiliation(s)
- Manoj Sehrawat
- Advanced Carbon Products and Metrology, CSIR – National Physical Laboratory, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Mamta Rani
- Advanced Carbon Products and Metrology, CSIR – National Physical Laboratory, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Pallvi Dariyal
- Advanced Carbon Products and Metrology, CSIR – National Physical Laboratory, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sony Bharadwaj
- Advanced Carbon Products and Metrology, CSIR – National Physical Laboratory, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - S. R. Dhakate
- Advanced Carbon Products and Metrology, CSIR – National Physical Laboratory, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Bhanu Pratap Singh
- Advanced Carbon Products and Metrology, CSIR – National Physical Laboratory, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
5
|
Liu J, Fan XR, Zhao W, Yang SW, Hu B, Yang SG, Lu Q. Mechanical insight into the formation of H 2S from thiophene pyrolysis: The influence of H 2O. CHEMOSPHERE 2021; 279:130628. [PMID: 34134421 DOI: 10.1016/j.chemosphere.2021.130628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/05/2021] [Accepted: 04/18/2021] [Indexed: 06/12/2023]
Abstract
The thermal utilization of waste rubber is accompanied by the release of sulfur, and the release of H2S to the gas phase is one of the crucial issues. In this work, density functional theory (DFT) calculations and wave function analysis were employed to explore the possible formation pathways of H2S and its precursor (·SH radical) during the pyrolysis of thiophene in the presence of H2O. It indicates that H2O affects the decomposition of thiophene and the formation of H2S in two patterns. First, H2O can participate in the hydrogen transfer process by acting as a catalyst or generating weak hydrogen bonds with thiophene. In this way, the hydrogen transfer reactions are promoted with lower energy barriers, and thus the formation of H2S is facilitated by H2O without changing the pyrolysis pathways. Secondly, H2O can saturate the thiophene ring by addition reactions and alter the generation pathways of H2S significantly. The energy barriers can be decreased with one or two CC bonds of thiophene being saturated. The completely saturated thiophene results in a greater decline of the overall energy barriers for H2S formation. H2O provides the H atom for H2S in the second pattern. Due to the combination of the two influence patterns, the release of H2S can be promoted greatly in the presence of H2O. The present study aims to lay a foundation for the clean thermal utilization of thiophene/rubber and to inspire the advance of desulfurization techniques.
Collapse
Affiliation(s)
- Ji Liu
- National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, Beijing, 102206, PR China; China Energy Engineering Group Anhui Electric Power Design Institute, Co., LTD, Hefei, Anhui Province, 230601, PR China
| | - Xin-Rui Fan
- National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, Beijing, 102206, PR China
| | - Wei Zhao
- National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, Beijing, 102206, PR China
| | - Shuang-Wei Yang
- National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, Beijing, 102206, PR China
| | - Bin Hu
- National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, Beijing, 102206, PR China
| | - Shi-Guan Yang
- National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, Beijing, 102206, PR China
| | - Qiang Lu
- National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, Beijing, 102206, PR China.
| |
Collapse
|
6
|
Li T, Zhang H, Li Y, Li J, Wang J, Xiao J. Theoretical Study on the Unimolecular Pyrolysis of Thiophene and Modeling. ACS OMEGA 2021; 6:20471-20482. [PMID: 34395994 PMCID: PMC8359137 DOI: 10.1021/acsomega.1c02155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Thiophenic sulfur is the most stable and abundant organic sulfur species in petroleum. Removal of thiophenes has profound significance in environmental protection. In this work, we investigate the unimolecular pyrolysis of thiophene from a kinetic perspective. High-level ab initio methods have been employed to deduce the potential energy surface. Rate coefficients of the elementary reactions are computed using variational transition-state theory at the CCSD(T)/CBS level to develop a kinetic model. By comparison with preceding experimental results, the kinetic model shows good performance in calculating the thiophene pyrolysis rate. The Arrhenius expression for thiophene unimolecular pyrolysis has been redetermined as k = 1.21 × 1013 × exp[(78.96 kcal/mol)/(RT)]. The unimolecular pyrolysis of thiophene is mainly initiated by the ring-H migrations, whereas the C-S bond rupture has limited contribution to the overall pyrolysis rate. Thioketene (SC2H2) and ethyne (C2H2) are the major pyrolysis products at all temperatures. Significant amounts of the thioformyl (HCS) radical and CS could also be yielded. By contrast, atomic sulfur and H2S are difficult to be directly produced. Possible secondary reactions in the products have also been discussed.
Collapse
Affiliation(s)
- Tianshuang Li
- School
of Metallurgy and Environment, Central South
University, Hunan
Province, Changsha 410083, China
- National
Engineering Laboratory of High Efficient Recovery of Refractory Nonferrous
Metals, Central South University, Hunan Province, Changsha 410083, China
| | - Hongliang Zhang
- School
of Metallurgy and Environment, Central South
University, Hunan
Province, Changsha 410083, China
- National
Engineering Laboratory of High Efficient Recovery of Refractory Nonferrous
Metals, Central South University, Hunan Province, Changsha 410083, China
| | - Yun Li
- School
of Metallurgy and Environment, Central South
University, Hunan
Province, Changsha 410083, China
| | - Jie Li
- School
of Metallurgy and Environment, Central South
University, Hunan
Province, Changsha 410083, China
- National
Engineering Laboratory of High Efficient Recovery of Refractory Nonferrous
Metals, Central South University, Hunan Province, Changsha 410083, China
| | - Jingkun Wang
- China
Hongqiao Group Limited, Zouping 256200, China
| | - Jin Xiao
- School
of Metallurgy and Environment, Central South
University, Hunan
Province, Changsha 410083, China
- National
Engineering Laboratory of High Efficient Recovery of Refractory Nonferrous
Metals, Central South University, Hunan Province, Changsha 410083, China
| |
Collapse
|
7
|
Tverdov I, Khafizov NR, Madzhidov TI, Varfolomeev MA, Yuan C, Kadkin ON. Theoretical Insights into the Catalytic Effect of Transition-Metal Ions on the Aquathermal Degradation of Sulfur-Containing Heavy Oil: A DFT Study of Cyclohexyl Phenyl Sulfide Cleavage. ACS OMEGA 2020; 5:19589-19597. [PMID: 32803053 PMCID: PMC7424706 DOI: 10.1021/acsomega.0c02069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
Steam injection is the most widely used technique for effectively reducing the viscosity of heavy oil in heavy oil production, in which in situ upgrading of heavy oil by aquathermolysis plays an important role. Earlier, transition-metal catalysts have been used for improving the efficiency of steam injection by catalytic aquathermolysis and achieving a higher degree of in situ oil upgrading. However, the unclear mechanism of aquathermolysis makes it difficult to choose efficient catalysts for different types of heavy oil. This theoretical study is aimed at deeply understanding the mechanism of in situ upgrading of sulfur-containing heavy oil and its catalysis. For this purpose, cyclohexyl phenyl sulfide (CPS) is selected as a model compound of sulfur-containing oil components, and, for the first time, a catalytic effect of transition metals on the thermochemistry and kinetics of its aquathermolysis is investigated by the density functional theory (DFT) methods with the use of the Becke three-parameter Lee-Yang-Parr (B3LYP), ωB97X-D, and M06-2X functionals. Calculation results show that the hydrolysis of CPS is characterized by fairly high energy barriers in comparison with other possible reaction routes leading to the cleavage of C-S bonds, while the heterolysis of C-S bonds in the presence of protons has a substantially lower kinetic barrier. According to the theoretical analysis, transition-metal ions significantly reduce the kinetic barrier of heterolysis. The Cu2+ ion outperforms the other investigated metal ions and the hydrogen ion in the calculated rate constant by 5-6 (depending on the metal) and 7 orders of magnitude, respectively. The catalytic activity of the investigated transition-metal ions is arranged in the following sequence, depending on the used DFT functional: Cu2+ ≫ Co2+ ≈ Ni2+ > Fe2+. It is theoretically confirmed that transition-metal ions, especially Cu2+, can serve as effective catalysts in aquathermolysis reactions. The proposed quantum-chemical approach for studying the catalytic aquathermolysis provides a new supplementary theoretical tool that can be used in the development of catalysts for different chemical transformations of heavy oil components in reservoirs due to hydrothermal treatment.
Collapse
Affiliation(s)
- Ilya Tverdov
- Alexander
Butlerov Institute of Chemistry, Kazan Federal
University, ul. Lobachevskogo 1/29, Kazan 420008, Russia
| | - Nail R. Khafizov
- Alexander
Butlerov Institute of Chemistry, Kazan Federal
University, ul. Lobachevskogo 1/29, Kazan 420008, Russia
| | - Timur I. Madzhidov
- Alexander
Butlerov Institute of Chemistry, Kazan Federal
University, ul. Lobachevskogo 1/29, Kazan 420008, Russia
| | - Mikhail A. Varfolomeev
- Alexander
Butlerov Institute of Chemistry, Kazan Federal
University, ul. Lobachevskogo 1/29, Kazan 420008, Russia
- Department
of Petroleum Engineering, Institute of Geology and Petroleum Technologies, Kazan Federal University, ul. Kremlevskaya 4/5, Kazan 420008, Russia
| | - Chengdong Yuan
- Alexander
Butlerov Institute of Chemistry, Kazan Federal
University, ul. Lobachevskogo 1/29, Kazan 420008, Russia
- Department
of Petroleum Engineering, Institute of Geology and Petroleum Technologies, Kazan Federal University, ul. Kremlevskaya 4/5, Kazan 420008, Russia
| | - Oleg N. Kadkin
- Alexander
Butlerov Institute of Chemistry, Kazan Federal
University, ul. Lobachevskogo 1/29, Kazan 420008, Russia
| |
Collapse
|
8
|
Rosi M, Skouteris D, Balucani N, Nappi C, Faginas Lago N, Pacifici L, Falcinelli S, Stranges D. An Experimental and Theoretical Investigation of 1-Butanol Pyrolysis. Front Chem 2019; 7:326. [PMID: 31139618 PMCID: PMC6527765 DOI: 10.3389/fchem.2019.00326] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/23/2019] [Indexed: 11/17/2022] Open
Abstract
Bioalcohols are a promising family of biofuels. Among them, 1-butanol has a strong potential as a substitute for petrol. In this manuscript, we report on a theoretical and experimental characterization of 1-butanol thermal decomposition, a very important process in the 1-butanol combustion at high temperatures. Advantage has been taken of a flash pyrolysis experimental set-up with mass spectrometric detection, in which the brief residence time of the pyrolyzing mixture inside a short, resistively heated SiC tube allows the identification of the primary products of the decomposing species, limiting secondary processes. Dedicated electronic structure calculations of the relevant potential energy surface have also been performed and RRKM estimates of the rate coefficients and product branching ratios up to 2,000 K are provided. Both electronic structure and RRKM calculations are in line with previous determinations. According to the present study, the H2O elimination channel leading to 1-butene is more important than previously believed. In addition to that, we provide experimental evidence that butanal formation by H2 elimination is not a primary decomposition route. Finally, we have experimental evidence of a small yield of the CH3 elimination channel.
Collapse
Affiliation(s)
- Marzio Rosi
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | | | - Nadia Balucani
- Laboratory of Molecular Processes in Combustion, Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Caterina Nappi
- Laboratory of Molecular Processes in Combustion, Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Noelia Faginas Lago
- Laboratory of Molecular Processes in Combustion, Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Leonardo Pacifici
- Master-Up, Perugia, Italy.,Laboratory of Molecular Processes in Combustion, Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Domenico Stranges
- Department of Chemistry, University of Rome "La Sapienza", Rome, Italy
| |
Collapse
|
9
|
Li T, Li J, Zhang H, Sun K, Xiao J. DFT Research on Benzothiophene Pyrolysis Reaction Mechanism. J Phys Chem A 2019; 123:796-810. [PMID: 30601656 DOI: 10.1021/acs.jpca.8b09882] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thiophene sulfur is the most stable organic sulfur species in petroleum coke, among which benzothiophene accounts for a significant portion. Removal of benzothiophene will help to gain ultralow desulfurization. In this work, a density function theory (DFT) method was adopted to investigate benzothiophene pyrolysis mechanism. It was found that the most possible pyrolysis reaction of benzothiophene is triggered by α-H migration to β-position. The dominating products are S radical and ethenethione, which could explain benzothiophene pyrolysis experiments well. Converting thiophene fused on aromatic to a thiol group could help to promote desulfurization. As a contrast, the thiophene pyrolysis reaction was also calculated at the same level. The initial pyrolysis temperature of benzothiophene and thiophene may be close, but the pyrolysis rate of thiophene is higher than that of benzothiophene. The implication of the benzothiophene pyrolysis mechanism may be beneficial for the development of new desulfurization technology.
Collapse
Affiliation(s)
- Tianshuang Li
- School of Metallurgy and Environment , Central South University , Hunan Province Changsha 410083 , China
| | - Jie Li
- School of Metallurgy and Environment , Central South University , Hunan Province Changsha 410083 , China
| | - Hongliang Zhang
- School of Metallurgy and Environment , Central South University , Hunan Province Changsha 410083 , China
| | - Kena Sun
- School of Metallurgy and Environment , Central South University , Hunan Province Changsha 410083 , China
| | - Jin Xiao
- School of Metallurgy and Environment , Central South University , Hunan Province Changsha 410083 , China
| |
Collapse
|