1
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Sun J, Dong J, Gao L, Zhao YQ, Moon H, Scott SL. Catalytic Upcycling of Polyolefins. Chem Rev 2024; 124:9457-9579. [PMID: 39151127 PMCID: PMC11363024 DOI: 10.1021/acs.chemrev.3c00943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 08/18/2024]
Abstract
The large production volumes of commodity polyolefins (specifically, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride)), in conjunction with their low unit values and multitude of short-term uses, have resulted in a significant and pressing waste management challenge. Only a small fraction of these polyolefins is currently mechanically recycled, with the rest being incinerated, accumulating in landfills, or leaking into the natural environment. Since polyolefins are energy-rich materials, there is considerable interest in recouping some of their chemical value while simultaneously motivating more responsible end-of-life management. An emerging strategy is catalytic depolymerization, in which a portion of the C-C bonds in the polyolefin backbone is broken with the assistance of a catalyst and, in some cases, additional small molecule reagents. When the products are small molecules or materials with higher value in their own right, or as chemical feedstocks, the process is called upcycling. This review summarizes recent progress for four major catalytic upcycling strategies: hydrogenolysis, (hydro)cracking, tandem processes involving metathesis, and selective oxidation. Key considerations include macromolecular reaction mechanisms relative to small molecule mechanisms, catalyst design for macromolecular transformations, and the effect of process conditions on product selectivity. Metrics for describing polyolefin upcycling are critically evaluated, and an outlook for future advances is described.
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Affiliation(s)
- Jiakai Sun
- Department
of Chemistry and Biochemistry, University
of California, Santa
Barbara, California 93106-9510, United States
| | - Jinhu Dong
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United
States
| | - Lijun Gao
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United
States
| | - Yu-Quan Zhao
- Department
of Chemistry and Biochemistry, University
of California, Santa
Barbara, California 93106-9510, United States
| | - Hyunjin Moon
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United
States
| | - Susannah L. Scott
- Department
of Chemistry and Biochemistry, University
of California, Santa
Barbara, California 93106-9510, United States
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United
States
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2
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Waldt C, Montalvo-Castro H, Almithn A, Loaiza-Orduz Á, Plaisance C, Hibbitts D. Role of Phosphorous in Transition Metal Phosphides for Selective Hydrogenolysis of Hindered C–O Bonds. J Catal 2023. [DOI: 10.1016/j.jcat.2023.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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3
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Berdugo-Díaz CE, Yun YS, Manetsch MT, Luo J, Barton DG, Chen X, Flaherty DW. Pathways for Reactions of Esters with H 2 over Supported Pd Catalysts: Elementary Steps, Site Requirements, and Particle Size Effects. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Claudia E. Berdugo-Díaz
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Yang Sik Yun
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Melissa T. Manetsch
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Jing Luo
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - David G. Barton
- Core R&D, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Xue Chen
- Dow Industrial Solutions, The Dow Chemical Company, Freeport, Texas 77566, United States
| | - David W. Flaherty
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
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4
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Gopeesingh J, Zhu R, Schuarca R, Yang W, Heyden A, Bond JQ. Kinetic and Mechanistic Analysis of the Hydrodeoxygenation of Propanoic Acid on Pt/SiO 2. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c03032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua Gopeesingh
- Department of Biomedical & Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Ran Zhu
- Department of Biomedical & Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Robson Schuarca
- Department of Biomedical & Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Wenqiang Yang
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Andreas Heyden
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Jesse Q. Bond
- Department of Biomedical & Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
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5
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Yun YS, Berdugo-Díaz CE, Flaherty DW. Advances in Understanding the Selective Hydrogenolysis of Biomass Derivatives. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02866] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Yang Sik Yun
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Claudia E. Berdugo-Díaz
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - David W. Flaherty
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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6
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Kopač D, Jurković DL, Likozar B, Huš M. First-Principles-Based Multiscale Modelling of Nonoxidative Butane Dehydrogenation on Cr 2O 3(0001). ACS Catal 2020; 10:14732-14746. [PMID: 33362945 PMCID: PMC7754517 DOI: 10.1021/acscatal.0c03197] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/16/2020] [Indexed: 11/29/2022]
Abstract
Propane (C3H8) and butane (C4H10) are short straight-chain alkane molecules that are difficult to convert catalytically. Analogous to propane, butane can be dehydrogenated to butenes (also known as butylenes) or butadiene, which are used industrially as raw materials when synthesizing various chemicals (plastics, rubbers, etc.). In this study, we present results of detailed first-principles-based multiscale modelling of butane dehydrogenation, consisting of three size- and time-scales. The reaction is modelled over Cr2O3(0001) chromium oxide, which is commonly used in the industrial setting. A complete 108-step reaction pathway of butane (C4H10) dehydrogenation was studied, yielding 1-butene (CH2CHCH2CH3) and 2-butene (CH3CHCHCH3), 1-butyne (CHCCH2CH3) and 2-butyne (CH3CCCH3), butadiene (CH2CHCHCH2), butenyne (CH2CHCCH), and ultimately butadiyne (CHCCCH). We include cracking and coking reactions (yielding C1, C2, and C3 hydrocarbons) in the model to provide a thorough description of catalyst deactivation as a function of the temperature and time. Density functional theory calculations with the Hubbard U model were used to study the reaction on the atomistic scale, resulting in the complete energetics and first-principles kinetic parameters for the dehydrogenation reaction. They were cast in a kinetic model using mean-field microkinetics and kinetic Monte Carlo simulations. The former was used to obtain gas equilibrium conditions in the steady-state regime, which were fed in the latter to provide accurate surface kinetics. A full reactor simulation was used to account for the macroscopic properties of the catalytic particles: their loading, specific surface area, and density and reactor parameters: size, design, and feed gas flow. With this approach, we obtained first-principles estimates of the catalytic conversion, selectivity to products, and time dependence of the catalyst activity, which can be paralleled to experimental data. We show that 2-butene is the most abundant product of dehydrogenation, with selectivity above 90% and turn-over frequency above 10-3 s-1 at T = 900 K. Butane conversion is below 5% at such low temperature, but rises above 40% at T > 1100 K. Activity starts to drop after ∼6 h because of surface poisoning with carbon. We conclude that the dehydrogenation of butane is a viable alternative to conventional olefin production processes.
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Affiliation(s)
- Drejc Kopač
- Department
of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Damjan Lašič Jurković
- Department
of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Blaž Likozar
- Department
of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Matej Huš
- Department
of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
- Association
for Technical Culture of Slovenia (ZOTKS), SI-1000 Ljubljana, Slovenia
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7
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Mark LO, Cendejas MC, Hermans I. The Use of Heterogeneous Catalysis in the Chemical Valorization of Plastic Waste. CHEMSUSCHEM 2020; 13:5808-5836. [PMID: 32997889 DOI: 10.1002/cssc.202001905] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/22/2020] [Indexed: 05/25/2023]
Abstract
Plastic solid waste (PSW) is an ever-growing environmental challenge for our society, as it not only ends up in landfills but also in waterways and oceans and is consequently entering the food chain. A key strategy to overcome this problem while also preserving carbon resources is to use PSW as a feedstock, evolving towards a circular economy. To implement this, mechanical as well as chemical recycling technologies must be developed. Indeed, owing to the high volume of PSW generated each year, mechanical recycling alone is not adequate for addressing this global challenge. Because of this, chemical recycling via thermal and heterogeneous catalytic conversion has received growing attention. This process has the potential to take PSW and convert it into usable monomers, fuels, synthesis gas, and adsorbents under more sustainable conditions than thermal degradation. This Review highlights the recent research advances in catalytic technologies for PSW conversion and valorization.
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Affiliation(s)
- Lesli O Mark
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Avenue, Madison, WI, 53706, USA
| | - Melissa C Cendejas
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Avenue, Madison, WI, 53706, USA
| | - Ive Hermans
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Avenue, Madison, WI, 53706, USA
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
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8
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Ko J, Muhlenkamp JA, Bonita Y, LiBretto NJ, Miller JT, Hicks JC, Schneider WF. Experimental and Computational Investigation of the Role of P in Moderating Ethane Dehydrogenation Performance over Ni-Based Catalysts. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c00908] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeonghyun Ko
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 250 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
| | - Jessica A. Muhlenkamp
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 250 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
| | - Yolanda Bonita
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 250 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
| | - Nicole J. LiBretto
- School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Jeffrey T. Miller
- School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Jason C. Hicks
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 250 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
| | - William F. Schneider
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 250 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States
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9
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Purdy SC, Seemakurthi RR, Mitchell GM, Davidson M, Lauderback BA, Deshpande S, Wu Z, Wegener EC, Greeley J, Miller JT. Structural trends in the dehydrogenation selectivity of palladium alloys. Chem Sci 2020; 11:5066-5081. [PMID: 34122964 PMCID: PMC8159209 DOI: 10.1039/d0sc00875c] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Alloying is well-known to improve the dehydrogenation selectivity of pure metals, but there remains considerable debate about the structural and electronic features of alloy surfaces that give rise to this behavior. To provide molecular-level insights into these effects, a series of Pd intermetallic alloy catalysts with Zn, Ga, In, Fe and Mn promoter elements was synthesized, and the structures were determined using in situ X-ray absorption spectroscopy (XAS) and synchrotron X-ray diffraction (XRD). The alloys all showed propane dehydrogenation turnover rates 5–8 times higher than monometallic Pd and selectivity to propylene of over 90%. Moreover, among the synthesized alloys, Pd3M alloy structures were less olefin selective than PdM alloys which were, in turn, almost 100% selective to propylene. This selectivity improvement was interpreted by changes in the DFT-calculated binding energies and activation energies for C–C and C–H bond activation, which are ultimately influenced by perturbation of the most stable adsorption site and changes to the d-band density of states. Furthermore, transition state analysis showed that the C–C bond breaking reactions require 4-fold ensemble sites, which are suggested to be required for non-selective, alkane hydrogenolysis reactions. These sites, which are not present on alloys with PdM structures, could be formed in the Pd3M alloy through substitution of one M atom with Pd, and this effect is suggested to be partially responsible for their slightly lower selectivity. Alloying is well-known to improve the dehydrogenation selectivity of pure metals, but there remains considerable debate about the structural and electronic features of alloy surfaces that give rise to this behavior.![]()
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Affiliation(s)
- Stephen C Purdy
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | | | - Garrett M Mitchell
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | - Mark Davidson
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | - Brooke A Lauderback
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | - Siddharth Deshpande
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | - Zhenwei Wu
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | - Evan C Wegener
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | - Jeffrey Greeley
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
| | - Jeffrey T Miller
- Davidson School of Chemical Engineering, Purdue University West Lafayette IN 47907 USA
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10
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Wu C, Wang L, Xiao Z, Li G, Wang L. Effects of van der Waals interactions on the dehydrogenation of n-butane on a Ni(1 1 1) surface. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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Almithn AS, Hibbitts DD. Impact of Metal and Heteroatom Identities in the Hydrogenolysis of C–X Bonds (X = C, N, O, S, and Cl). ACS Catal 2020. [DOI: 10.1021/acscatal.0c00481] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Abdulrahman S. Almithn
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
- Department of Chemical Engineering, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - David D. Hibbitts
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
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12
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Gao X, Dai H, Peng L, Lu D, Wan X, Zhou C, Zheng J, Dai Y, Wang H, Yang Y. Effect of Hydrotalcites Interlayer Water on Pt-Catalyzed Aqueous-Phase Selective Hydrogenation of Cinnamaldehyde. ACS APPLIED MATERIALS & INTERFACES 2020; 12:2516-2524. [PMID: 31854963 DOI: 10.1021/acsami.9b19160] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The heterogeneous hydrogenation of α,β-unsaturated compounds requires understanding of the structure-activity relationship of metallic catalysts in consideration of solvent-mediated processes. In this work, a CoAl hydrotalcites (CoAl-HTs)-supported Pt nanoparticle catalyst is employed to study the effect of solvent water and HTs interlayer water on the aqueous-phase selective hydrogenation of cinnamaldehyde (CALD). Pt/Co2Al1-HTs catalyst displays 5075 h-1 of specific reaction rate and 89% of C═O hydrogenation selectivity at 80 °C under 20 bar of H2. Combined results of isotope-labeling experiments and theoretical DFT calculations demonstrate that the water-mediated hydrogen-exchange pathway exists in the reaction with a relatively lower-energy barrier in comparison to the direct H2-dissociated hydrogenation pathway. The results also reveal that the interlayer water species of HTs support participate in the hydrogen-exchange reaction. Based on the H2-D2 exchange results, these HTs interlayer water species can promote H2 activation and dissociation processes and thus accelerate the CALD hydrogenation reaction even under solvent-free conditions.
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Affiliation(s)
- Xing Gao
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Hua Dai
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Lilin Peng
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Di Lu
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Xiaoyue Wan
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Chunmei Zhou
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Jianwei Zheng
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Yihu Dai
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
| | - Hongming Wang
- Institute of Advanced Study, College of Chemistry , Nanchang University , Nanchang 330031 , China
| | - Yanhui Yang
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering , Nanjing Tech University , Nanjing 211816 , China
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13
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Sampath A, Flaherty DW. Effects of phosphorus addition on selectivity and stability of Pd model catalysts during cyclohexene dehydrogenation. Catal Sci Technol 2020. [DOI: 10.1039/c9cy02134e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
P addition to Pd increases dehydrogenation selectivity and increases catalyst stability.
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Affiliation(s)
- Abinaya Sampath
- Department of Chemical and Biomolecular Engineering
- University of Illinois Urbana-Champaign
- Urbana
- USA
| | - David W. Flaherty
- Department of Chemical and Biomolecular Engineering
- University of Illinois Urbana-Champaign
- Urbana
- USA
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14
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Wu C, Wang L, Xiao Z, Li G, Wang L. Understanding deep dehydrogenation and cracking of n-butane on Ni(111) by a DFT study. Phys Chem Chem Phys 2020; 22:724-733. [DOI: 10.1039/c9cp05022a] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A DFT study on deep dehydrogenation and cracking of long-chain hydrocarbon involving the cleavage of different C–C bonds on nickel.
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Affiliation(s)
- Chan Wu
- Key Laboratory for Green Chemical Technology of Ministry of Education
- School of Chemical Engineering and Technology
- Collaborative Innovative Center of Chemical Science and Engineering (Tianjin)
- Tianjin University
- Tianjin 300072
| | - Li Wang
- Key Laboratory for Green Chemical Technology of Ministry of Education
- School of Chemical Engineering and Technology
- Collaborative Innovative Center of Chemical Science and Engineering (Tianjin)
- Tianjin University
- Tianjin 300072
| | - Zhourong Xiao
- Key Laboratory for Green Chemical Technology of Ministry of Education
- School of Chemical Engineering and Technology
- Collaborative Innovative Center of Chemical Science and Engineering (Tianjin)
- Tianjin University
- Tianjin 300072
| | - Guozhu Li
- Key Laboratory for Green Chemical Technology of Ministry of Education
- School of Chemical Engineering and Technology
- Collaborative Innovative Center of Chemical Science and Engineering (Tianjin)
- Tianjin University
- Tianjin 300072
| | - Lichang Wang
- Department of Chemistry and Biochemistry
- Southern Illinois University
- Carbondale
- USA
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15
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Celik G, Kennedy RM, Hackler RA, Ferrandon M, Tennakoon A, Patnaik S, LaPointe AM, Ammal SC, Heyden A, Perras F, Pruski M, Scott SL, Poeppelmeier KR, Sadow AD, Delferro M. Upcycling Single-Use Polyethylene into High-Quality Liquid Products. ACS CENTRAL SCIENCE 2019; 5:1795-1803. [PMID: 31807681 PMCID: PMC6891864 DOI: 10.1021/acscentsci.9b00722] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Indexed: 05/18/2023]
Abstract
Our civilization relies on synthetic polymers for all aspects of modern life; yet, inefficient recycling and extremely slow environmental degradation of plastics are causing increasing concern about their widespread use. After a single use, many of these materials are currently treated as waste, underutilizing their inherent chemical and energy value. In this study, energy-rich polyethylene (PE) macromolecules are catalytically transformed into value-added products by hydrogenolysis using well-dispersed Pt nanoparticles (NPs) supported on SrTiO3 perovskite nanocuboids by atomic layer deposition. Pt/SrTiO3 completely converts PE (M n = 8000-158,000 Da) or a single-use plastic bag (M n = 31,000 Da) into high-quality liquid products, such as lubricants and waxes, characterized by a narrow distribution of oligomeric chains, at 170 psi H2 and 300 °C under solvent-free conditions for reaction durations up to 96 h. The binding of PE onto the catalyst surface contributes to the number averaged molecular weight (M n) and the narrow polydispersity (Đ) of the final liquid product. Solid-state nuclear magnetic resonance of 13C-enriched PE adsorption studies and density functional theory computations suggest that PE adsorption is more favorable on Pt sites than that on the SrTiO3 support. Smaller Pt NPs with higher concentrations of undercoordinated Pt sites over-hydrogenolyzed PE to undesired light hydrocarbons.
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Affiliation(s)
- Gokhan Celik
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Robert M. Kennedy
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Ryan A. Hackler
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Magali Ferrandon
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Akalanka Tennakoon
- U.S.
DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Smita Patnaik
- U.S.
DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Anne M. LaPointe
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14583, United
States
| | - Salai C. Ammal
- Department
of Chemical Engineering, University of South
Carolina, Columbia, South Carolina 29208, United States
| | - Andreas Heyden
- Department
of Chemical Engineering, University of South
Carolina, Columbia, South Carolina 29208, United States
| | | | - Marek Pruski
- U.S.
DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Susannah L. Scott
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Kenneth R. Poeppelmeier
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- (K.R.P.) E-mail:
| | - Aaron D. Sadow
- U.S.
DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- (A.D.S.) E-mail:
| | - Massimiliano Delferro
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
- (M.D.) E-mail:
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16
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Witzke ME, Almithn A, Conrad CL, Triezenberg MD, Hibbitts DD, Flaherty DW. In Situ Methods for Identifying Reactive Surface Intermediates during Hydrogenolysis Reactions: C–O Bond Cleavage on Nanoparticles of Nickel and Nickel Phosphides. J Am Chem Soc 2019; 141:16671-16684. [DOI: 10.1021/jacs.9b06112] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Megan E. Witzke
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Abdulrahman Almithn
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Christian L. Conrad
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Mark D. Triezenberg
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - David D. Hibbitts
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - David W. Flaherty
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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17
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Methane and Ethane Steam Reforming over MgAl2O4-Supported Rh and Ir Catalysts: Catalytic Implications for Natural Gas Reforming Application. Catalysts 2019. [DOI: 10.3390/catal9100801] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Solar concentrators employed in conjunction with highly efficient micro- and meso-channel reactors offer the potential for cost-effective upgrading of the energy content of natural gas, providing a near-term path towards a future solar-fuel economy with reduced carbon dioxide emissions. To fully exploit the heat and mass transfer advantages offered by micro- and meso-channel reactors, highly active and stable natural gas steam reforming catalysts are required. In this paper, we report the catalytic performance of MgAl2O4-supported Rh (5 wt.%), Ir (5 wt.%), and Ni (15 wt.%) catalysts used for steam reforming of natural gas. Both Rh- and Ir-based catalysts are known to be more active and durable than conventional Ni-based formulations, and recently Ir has been reported to be more active than Rh for methane steam reforming on a turnover basis. Thus, the effectiveness of all three metals to perform natural gas steam reforming was evaluated in this study. Here, the Rh- and Ir-supported catalysts both exhibited higher activity than Ni for steam methane reforming. However, using simulated natural gas feedstock (94.5% methane, 4.0% ethane, 1.0% propane, and 0.5% butane), the Ir catalyst was the least active (on a turnover basis) for steam reforming of higher hydrocarbons (C2+) contained in the feedstock when operated at <750 °C. To further investigate the role of higher hydrocarbons, we used an ethane feed and found that hydrogenolysis precedes the steam reforming reaction and that C–C bond scission over Ir is kinetically slow compared to Rh. Catalyst durability studies revealed the Rh catalyst to be stable under steam methane reforming conditions, as evidenced by two 100-hour duration experiments performed at 850 and 900 °C (steam to carbon [S/C] molar feed ratio = 2.0 mol). However, with the natural gas simulant feed, the Rh catalyst exhibited catalyst deactivation, which we attribute to coking deposits derived from higher hydrocarbons contained in the feedstock. Increasing the S/C molar feed ratio from 1.5 to 2.0 reduced the deactivation rate and stable catalytic performance was demonstrated for 120 h when operated at 850 °C. However, catalytic deactivation was observed when operating at 900 °C. While improvements in steam reforming performance can be achieved through choice of catalyst composition, this study also highlights the importance of considering the effect of higher hydrocarbons contained in natural gas, operating conditions (e.g., temperature, S/C feed ratio), and their effect on catalyst stability. The results of this study conclude that a Rh-supported catalyst was developed that enables very high activities and excellent catalytic stability for both the steam reforming of methane and other higher hydrocarbons contained in natural gas, and under conditions of operation that are amendable to solar thermochemical operations.
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18
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DeLuca M, Kravchenko P, Hoffman A, Hibbitts D. Mechanism and Kinetics of Methylating C6–C12 Methylbenzenes with Methanol and Dimethyl Ether in H-MFI Zeolites. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00650] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mykela DeLuca
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Pavlo Kravchenko
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Alexander Hoffman
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - David Hibbitts
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
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19
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Mechanism and site requirements for thiophene hydrodesulfurization on supported Re domains in metal or sulfide form. J Catal 2018. [DOI: 10.1016/j.jcat.2018.03.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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20
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Almithn A, Hibbitts D. Effects of Catalyst Model and High Adsorbate Coverages in ab Initio Studies of Alkane Hydrogenolysis. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01114] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Abdulrahman Almithn
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - David Hibbitts
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
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21
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Almithn AS, Hibbitts DD. Supra-monolayer coverages on small metal clusters and their effects on H2
chemisorption particle size estimates. AIChE J 2018. [DOI: 10.1002/aic.16110] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - David D. Hibbitts
- Dept. of Chemical Engineering; University of Florida; Gainesville FL 32611
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22
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Peng G, Gerceker D, Kumbhalkar M, Dumesic JA, Mavrikakis M. Ethane dehydrogenation on pristine and AlOx decorated Pt stepped surfaces. Catal Sci Technol 2018. [DOI: 10.1039/c8cy00398j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Atomic layer deposition (ALD) alumina overcoating over Pt enhances ethylene production and decreases coke formation in ethane dehydrogenation.
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Affiliation(s)
- Guowen Peng
- Department of Chemical and Biological Engineering
- University of Wisconsin-Madison
- Madison
- USA
| | - Duygu Gerceker
- Department of Chemical and Biological Engineering
- University of Wisconsin-Madison
- Madison
- USA
| | - Mrunmayi Kumbhalkar
- Department of Chemical and Biological Engineering
- University of Wisconsin-Madison
- Madison
- USA
| | - James A. Dumesic
- Department of Chemical and Biological Engineering
- University of Wisconsin-Madison
- Madison
- USA
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering
- University of Wisconsin-Madison
- Madison
- USA
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23
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Sullivan MM, Bhan A. Effects of oxygen coverage on rates and selectivity of propane-CO2 reactions on molybdenum carbide. J Catal 2018. [DOI: 10.1016/j.jcat.2017.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Meyer RJ, Zhang Q, Kryczka A, Gomez C, Todorovic R. Perturbation of Reactivity with Geometry: How Far Can We Go? ACS Catal 2017. [DOI: 10.1021/acscatal.7b03228] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Randall J. Meyer
- ExxonMobil Research and Engineering, Annandale, New Jersey 08801, United States
| | - Qiang Zhang
- Department
of Chemical Engineering, University of Illinois at Chicago, Chicago Illinois 60607, United States
| | - Anna Kryczka
- Illinois Math and Science Academy, Aurora, Illinois 60506, United States
| | - Carolina Gomez
- Department
of Chemical Engineering, University of Illinois at Chicago, Chicago Illinois 60607, United States
| | - Ruzica Todorovic
- Department
of Chemical Engineering, University of Illinois at Chicago, Chicago Illinois 60607, United States
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25
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Zhu Q, Wang G, Liu J, Su L, Li C. Effect of Sn on Isobutane Dehydrogenation Performance of Ni/SiO 2 Catalyst: Adsorption Modes and Adsorption Energies of Isobutane and Isobutene. ACS APPLIED MATERIALS & INTERFACES 2017; 9:30711-30721. [PMID: 28805375 DOI: 10.1021/acsami.7b09482] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The reaction of isobutane over Ni/SiO2 catalyst changes from hydrogenolysis to dehydrogenation when Sn is introduced. The adsorption modes and energies of isobutane and isobutene over the Ni/SiO2 catalyst with and without Sn addition were determined by in situ FTIR and a novel transient response adsorption approach. In the absence of Sn, isobutane is adsorbed in a double-site mode with H atoms in two methyl groups of isobutane, facilitating hydrogenolysis of isobutane. After the addition of Sn, a single-site adsorption mode with the H atom in the methylidyne group is speculated instead, which is beneficial to the rupture of the C-H bond rather than the C-C bond. Moreover, the double-site adsorption mode of isobutene with the C═C bond and the H atom in a methyl group is turned into single-site mode with the C═C bond after the introduction of Sn. As for the adsorption energy of isobutene, the introduction of Sn leads to an obvious decrease from 74 to 50 kJ mol-1 and facilitates the prompt desorption of isobutene, resulting in a high selectivity of 81.9 wt %.
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Affiliation(s)
- Qingqing Zhu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Qingdao, 266580, China
| | - Guowei Wang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Qingdao, 266580, China
| | - Jianwei Liu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Qingdao, 266580, China
| | - Lushu Su
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Qingdao, 266580, China
| | - Chunyi Li
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Qingdao, 266580, China
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26
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Nakagawa Y, Oya SI, Kanno D, Nakaji Y, Tamura M, Tomishige K. Regioselectivity and Reaction Mechanism of Ru-Catalyzed Hydrogenolysis of Squalane and Model Alkanes. CHEMSUSCHEM 2017; 10:189-198. [PMID: 27863013 DOI: 10.1002/cssc.201601204] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/12/2016] [Indexed: 05/25/2023]
Abstract
The dependence of the C-C hydrogenolysis activity on reaction parameters and the structure of the substrate alkanes was investigated for Ru/CeO2 catalyst with very small (dispersion: H/Ru=0.89) Ru particles. The substrate concentration and reaction temperature did not have a significant effect on the selectivity pattern, except that methane production was promoted at high temperatures. However, the hydrogen pressure had a marked effect on the selectivity pattern. Ctertiary -C bond dissociation, terminal Csecondary -Cprimary bond dissociation, and fragmentation to form excess methane had negative reaction order with respect to hydrogen partial pressure, whereas Csecondary -Csecondary bond dissociation had an approximately zero reaction order. Therefore, a high hydrogen pressure is essential for the regioselective hydrogenolysis of Csecondary -Csecondary bonds in squalane. Ru/SiO2 catalyst with larger Ru particles showed similar changes in the product distribution during the change in hydrogen pressure. The reaction mechanism for each type of C-C bond dissociation is proposed based on reactivity trends and DFT calculations. The proposed intermediate species for the internal Csecondary -Csecondary dissociation, terminal Csecondary -Cprimary dissociation, and Ctertiary -C dissociation is alkyls, alkylidynes, and alkenes, respectively.
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Affiliation(s)
- Yoshinao Nakagawa
- Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
- Research Center for Rare Metal and Green Innovation, Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai, 980-0845, Japan
| | - Shin-Ichi Oya
- Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
| | - Daisuke Kanno
- Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
| | - Yosuke Nakaji
- Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
| | - Masazumi Tamura
- Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
- Research Center for Rare Metal and Green Innovation, Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai, 980-0845, Japan
| | - Keiichi Tomishige
- Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
- Research Center for Rare Metal and Green Innovation, Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai, 980-0845, Japan
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27
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Moskaleva L, Chiu CC, Genest A, Rösch N. Transformations of Organic Molecules over Metal Surfaces: Insights from Computational Catalysis. CHEM REC 2016; 16:2388-2404. [DOI: 10.1002/tcr.201600048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Indexed: 01/20/2023]
Affiliation(s)
- Lyudmila Moskaleva
- Institute of Applied and Physical Chemistry and Center for Environmental Research and Sustainable Technology Universität Bremen; 28359 Bremen Germany
| | - Cheng-chau Chiu
- Institute of Atomic and Molecular Sciences; Academia Sinica Taipei 10617 Taiwan
| | - Alexander Genest
- Institute of High Performance Computing Agency for Science, Technology and Research; 1 Fusionopolis Way Connexis #16-16 Singapore 138632 Singapore
| | - Notker Rösch
- Institute of High Performance Computing Agency for Science, Technology and Research; 1 Fusionopolis Way Connexis #16-16 Singapore 138632 Singapore
- Department Chemie and Catalysis Research Center; Technische Universität München; 85747 Garching Germany
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28
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Hibbitts DD, Flaherty DW, Iglesia E. Role of Branching on the Rate and Mechanism of C–C Cleavage in Alkanes on Metal Surfaces. ACS Catal 2015. [DOI: 10.1021/acscatal.5b01950] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David D. Hibbitts
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
- Department
of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - David W. Flaherty
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
- Department
of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Enrique Iglesia
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
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29
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Tan Q, Wang G, Nie L, Dinse A, Buda C, Shabaker J, Resasco DE. Different Product Distributions and Mechanistic Aspects of the Hydrodeoxygenation of m-Cresol over Platinum and Ruthenium Catalysts. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00765] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Qiaohua Tan
- School
of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Gonghua Wang
- School
of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Lei Nie
- School
of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Arne Dinse
- Center of Expertise for Applied Chemistry & Physics, BP Products North America Incorporated, Naperville, Illinois 60563, United States
| | - Corneliu Buda
- Center of Expertise for Applied Chemistry & Physics, BP Products North America Incorporated, Naperville, Illinois 60563, United States
| | - John Shabaker
- Center of Expertise for Applied Chemistry & Physics, BP Products North America Incorporated, Naperville, Illinois 60563, United States
| | - Daniel E. Resasco
- School
of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States
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30
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Gürbüz EI, Hibbitts DD, Iglesia E. Kinetic and Mechanistic Assessment of Alkanol/Alkanal Decarbonylation and Deoxygenation Pathways on Metal Catalysts. J Am Chem Soc 2015; 137:11984-95. [DOI: 10.1021/jacs.5b05361] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elif I. Gürbüz
- Department of Chemical and Biomolecular Engineering and ‡Division of Chemical
Sciences,
E. O. Lawrence Berkeley National Laboratory, University of California at Berkeley, Berkeley, California 94720, United States
| | - David D. Hibbitts
- Department of Chemical and Biomolecular Engineering and ‡Division of Chemical
Sciences,
E. O. Lawrence Berkeley National Laboratory, University of California at Berkeley, Berkeley, California 94720, United States
| | - Enrique Iglesia
- Department of Chemical and Biomolecular Engineering and ‡Division of Chemical
Sciences,
E. O. Lawrence Berkeley National Laboratory, University of California at Berkeley, Berkeley, California 94720, United States
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31
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Effect of the Size of Iron Nanoparticles on the Catalytic Activity and Selectivity of Fe/Cnt Nanocomposites in Hydrogenolysis of Ethylene. THEOR EXP CHEM+ 2015. [DOI: 10.1007/s11237-015-9405-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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32
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Flaherty DW, Hibbitts DD, Iglesia E. Metal-catalyzed C-C bond cleavage in alkanes: effects of methyl substitution on transition-state structures and stability. J Am Chem Soc 2014; 136:9664-76. [PMID: 24961991 DOI: 10.1021/ja5037429] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methyl substituents at C-C bonds influence hydrogenolysis rates and selectivities of acyclic and cyclic C2-C8 alkanes on Ir, Rh, Ru, and Pt catalysts. C-C cleavage transition states form via equilibrated dehydrogenation steps that replace several C-H bonds with C-metal bonds, desorb H atoms (H*) from saturated surfaces, and form λ H2(g) molecules. Activation enthalpies (ΔH(‡)) and entropies (ΔS(‡)) and λ values for (3)C-(x)C cleavage are larger than for (2)C-(2)C or (2)C-(1)C bonds, irrespective of the composition of metal clusters or the cyclic/acyclic structure of the reactants. (3)C-(x)C bonds cleave through α,β,γ- or α,β,γ,δ-bound transition states, as indicated by the agreement between measured activation entropies and those estimated for such structures using statistical mechanics. In contrast, less substituted C-C bonds involve α,β-bound species with each C atom bound to several surface atoms. These α,β configurations weaken C-C bonds through back-donation to antibonding orbitals, but such configurations cannot form with (3)C atoms, which have one C-H bond and thus can form only one C-M bond. (3)C-(x)C cleavage involves attachment of other C atoms, which requires endothermic C-H activation and H* desorption steps that lead to larger ΔH(‡) values but also larger ΔS(‡) values (by forming more H2(g)) than for (2)C-(2)C and (2)C-(1)C bonds, irrespective of alkane size (C2-C8) or cyclic/acyclic structure. These data and their mechanistic interpretation indicate that low temperatures and high H2 pressures favor cleavage of less substituted C-C bonds and form more highly branched products from cyclic and acyclic alkanes. Such interpretations and catalytic consequences of substitution seem also relevant to C-X cleavage (X = S, N, O) in desulfurization, denitrogenation, and deoxygenation reactions.
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Affiliation(s)
- David W Flaherty
- Department of Chemical Engineering, University of California at Berkeley , Berkeley, California 94720, United States
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33
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Childers DJ, Schweitzer NM, Shahri SMK, Rioux RM, Miller JT, Meyer RJ. Evidence for geometric effects in neopentane conversion on PdAu catalysts. Catal Sci Technol 2014. [DOI: 10.1039/c4cy00846d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Silica-supported Pd and Pd(shell)/Au(core) nanoparticles of a similar size were evaluated for neopentane conversion.
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Affiliation(s)
- David J. Childers
- Department of Chemical Engineering
- University of Illinois at Chicago
- USA
| | | | | | - Robert M. Rioux
- Department of Chemical Engineering
- The Pennsylvania State University
- USA
| | - Jeffrey T. Miller
- Division of Chemical Sciences and Engineering
- Argonne National Laboratory
- USA
| | - Randall J. Meyer
- Department of Chemical Engineering
- University of Illinois at Chicago
- USA
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