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Sun Y, Mao X, Pei S. A two-layer ONIOM study of thiophene cracking catalyzed by proton- and cation-exchanged FAU zeolite. J Mol Model 2016; 22:51. [PMID: 26841976 DOI: 10.1007/s00894-016-2916-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/18/2016] [Indexed: 11/26/2022]
Abstract
A two-layer ONIOM study on the hydrodesulfurization mechanism of thiophene in H-FAU and M-FAU (M = Li(+), Na(+), and K(+)) has been carried out. The calculated results reveal that in H-FAU, for a unimolecular mechanism, the rate-determining step is hydrogenation of alkoxide intermediate. The assistance of H2O and H2S molecules does not reduce the difficulty of the C-S bond cracking step more effectively. A bimolecular hydrodesulfurization mechanism is more favorable due to the lower activation barriers. The rate-determining step is the formation of 2-methylthiophene, not the C-S bond cracking of thiophene. Moreover, the ring opening of thiophene is much easier to occur than the desulfurization step. A careful analysis of energetics indicates that H2S, propene, and methyl thiophene are the major products for the hydrodesulfurization process of thiophene over H-FAU zeolite, in good agreement with experimental findings. In M-FAU zeolites, both unimolecular and bimolecular cracking processes are difficult to occur because of the high energy barriers. Compared to the case on H-FAU, the metal cations on M-FAU increase the difficulty of occurrence of bimolecular polymerization and subsequent C-S bond cracking steps. Graphical abstract Hydrodesulfurization process of thiophene can take place in H-FAU zeolite. Two different mechanisms, unimolecular and bimolecular ones, have been proposed and evaluated in detail. The bimolecular mechanism is more favorable due to lower activation barrier as described in the picture above. Our calculated data indicate that H2S, propene, and methylthiophene are the major products, in good agreement with experimental observations. The effect of metal cations on the reaction mechanism is also investigated in this work.
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Affiliation(s)
- Yingxin Sun
- School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, China.
| | - Xinfeng Mao
- School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, China
| | - Supeng Pei
- School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, China.
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Mao X, Sun Y, Pei S. A theoretical investigation into thiophenic derivative cracking mechanism over acidic and cation-exchanged beta zeolites. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2015.10.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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ROOHI HOSSEIN, JAHANTAB MAHJOUBEH. Adsorption of parent nitrosamine on the nanocrystaline M-ZSM-5 zeolite: A density functional study. J CHEM SCI 2013. [DOI: 10.1007/s12039-013-0453-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Nie X, Janik MJ, Guo X, Song C. A computational investigation of ring-shift isomerization of sym-octahydrophenanthrene to sym-octahydroanthracene catalyzed by acidic zeolites. Phys Chem Chem Phys 2012; 14:16644-53. [DOI: 10.1039/c2cp41824j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sirijaraensre J, Limtrakul J. Effect of the acidic strength on the vapor phase Beckmann rearrangement of cyclohexanone oxime over the MFI zeolite: an embedded ONIOM study. Phys Chem Chem Phys 2009; 11:578-85. [DOI: 10.1039/b808662a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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The adsorption of saturated and unsaturated hydrocarbons on nanostructured zeolites (H-MOR and H-FAU): An ONIOM study. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.molcata.2007.07.037] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Jungsuttiwong S, Limtrakul J, Truong TN. Theoretical study of modes of adsorption of water dimer on H-ZSM-5 and H-Faujasite zeolites. J Phys Chem B 2007; 109:13342-51. [PMID: 16852665 DOI: 10.1021/jp045021k] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Modes of adsorption of water dimer on H-ZSM-5 and H-Faujasite (H-FAU) zeolites have been investigated by a quantum embedded cluster approach, using the hybrid B3LYP density functional theory. The results indicate that there are two possible adsorption pathways, namely the stepwise process where only one water binds strongly to the (-O)3-Al-O(H) tetrahedral unit while the other weakly binds to the zeolite framework and the concerted process where both water molecules form a large ring of hydrogen-bonding network with the Brønsted proton and an oxygen framework. With inclusion of the effects of the Madelung potential from the extended zeolite framework, for adsorption on H-ZSM-5 zeolite, both the neutral and ion-pair complexes exist with adsorption energies of -15.13 and -14.73 kcal/mol, respectively. For adsorption on the H-FAU, only the ion-pair complex exists with the adsorption energy of -14.63 kcal/mol. Our results indicate that adsorption properties depend not only on the acidity of the Brønsted acidic site but also on the topology of the zeolite framework, such as on the spatial confinement effects which lead to very different adsorption structures for the ion-pair complexes in H-ZSM-5 and H-FAU, even though their adsorption energies are quite similar. Our calculated vibrational spectra for these ion-pair complexes support previous experimental IR interpretations.
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Affiliation(s)
- Siriporn Jungsuttiwong
- Henry Eyring Center for Theoretical Chemistry, Chemistry Department, University of Utah, 315 S 1400 E, Room 2020, Salt Lake City, Utah 84112, USA
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Jansang B, Nanok T, Limtrakul J. Interaction of mordenite with an aromatic hydrocarbon: An embedded ONIOM study. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.molcata.2006.06.054] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Namuangruk S, Khongpracha P, Pantu P, Limtrakul J. Structures and Reaction Mechanisms of Propene Oxide Isomerization on H-ZSM-5: An ONIOM Study. J Phys Chem B 2006; 110:25950-7. [PMID: 17181244 DOI: 10.1021/jp065266s] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The isomerization mechanisms of propene oxide over H-ZSM-5 zeolite have been investigated via the utilization of 5T and 46T cluster models calculated by the B3LYP/6-31G(d,p) and the ONIOM(B3LYP/6-31G(d,p):UFF) methods, respectively. The reactions are considered to proceed through a stepwise mechanism: (1) the epoxide ring protonation, and concurrently the ring-opening, and (2) the 1,2-hydride shift forming the adsorbed carbonyl compound. Because of the asymmetric structure of propene oxide, two different C-O bonds (more or less substituted carbon atom sides) can be broken leading to two different types of products, propanal and propanone. The ring-opening step of these mechanisms is found to be the rate-determining step with an activation barrier of 38.5 kcal/mol for the propanal and of 42.4 kcal/mol for the propanone. Therefore, the propanal is predicted to be the main product for this reaction.
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Affiliation(s)
- Supawadee Namuangruk
- Laboratory for Computational and Applied Chemistry, Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
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Sirijaraensre J, Limtrakul J. Vapor-Phase Beckmann Rearrangement of Oxime Molecules over H-Faujasite Zeolite. Chemphyschem 2006; 7:2424-32. [PMID: 17004280 DOI: 10.1002/cphc.200600403] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The Beckmann rearrangement (BR) plays an important role in a variety of industries. The mechanism of this reaction rearrangement of oximes with different molecular sizes, specifically, the oximes of formaldehyde (H(2)C=NOH), Z-acetaldehyde (CH(3)HC=NOH), E-acetaldehyde (CH(3)HC=NOH) and acetone (CH(3))(2)C=NOH, catalyzed by the Faujasite zeolite is investigated by both the quantum cluster and embedded cluster approaches at the B3LYP level of theory using the 6-31G (d,p) basis set. To enhance the energetic properties, single point calculations are undertaken at MP2/6-311G(d,p). The rearrangement step, using the bare cluster model, is the rate determining step of the entire reaction of these oxime molecules of which the energy barrier is between 50-70 kcal mol(-1). The more accurate embedded cluster model, in which the effect of the zeolitic framework is included, yields as the rate determining step, the formaldehyde oxime reaction rearrangement with an energy barrier of 50.4 kcal mol(-1). With the inclusion of the methyl substitution at the carbon-end of formaldehyde oxime, the rate determining step of the reaction becomes the 1,2 H-shift step for Z-acetaldehyde oxime (30.5 kcal mol(-1)) and acetone oxime (31.2 kcal mol(-1)), while, in the E-acetaldehyde oxime, the rate determining step is either the 1,2 H-shift (26.2 kcal mol(-1)) or the rearrangement step (26.6 kcal mol(-1)). These results signify the important role that the effect of the zeolite framework plays in lowering the activation energy by stabilizing all of the ionic species in the process. It should, however, be noted that the sizeable turnover of a reaction catalyzed by the Brønsted acid site might be delayed by the quantitatively high desorption energy of the product and readsorption of the reactant at the active center.
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Affiliation(s)
- Jakkapan Sirijaraensre
- Laboratory for Computational and Applied Chemistry, Chemistry Department, Faculty of Science, Kasetsart University, Bangkok, Thailand
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Sirijaraensre J, Truong TN, Limtrakul J. Density Functional Study of the Mechanism of the Beckmann Rearrangement Catalyzed by H-ZSM-5: A Cluster and Embedded Cluster Study. J Phys Chem B 2005; 109:12099-106. [PMID: 16852493 DOI: 10.1021/jp045135w] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism of the Beckmann rearrangement (BR) catalyzed by the ZSM-5 zeolite has been investigated by both the quantum cluster and embedded cluster approaches at the B3LYP level of theory using the 6-31G(d,p) basis set. Single-point calculations were carried out at the MP2/6-311G(d,p) level of theory to improve energetic properties. The embedded cluster model suggests that the initial step of the Beckmann rearrangement is not the O-protonated oxime but the N-protonated oxime. The energy barriers derived from the proton shuttle of the N-bound to the O-bound isomer are determined to be approximately 99 and approximately 40 kJ/mol for the embedded cluster and quantum cluster approaches, respectively. The difference in the activation energy is due mainly to the effect of the Madelung potential from the zeolite framework. The next step is the rearrangement step, which is the transformation of the O-protonated oxime to be an enol-formed amide compound, formimidic acid. The activation energy, at the rearrangement step, is calculated to be approximately 125 and approximately 270 kJ/mol for the embedded cluster and quantum cluster approaches, respectively. The final step is the tautomerization step which transforms the enol-form to the keto-form, formamide compound. The energy barrier for tautomerization is calculated to be 123 and 151 kJ/mol for the embedded cluster and quantum cluster approaches, respectively. These calculated results suggest that the rate-determining step of the vapor phase of the Beckmann rearrangement on H-ZSM-5 is the rearrangement or tautomerization step.
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Affiliation(s)
- Jakkapan Sirijaraensre
- Computational and Applied Chemistry Laboratory, Physical Chemistry Division, Kasetsart University, Bangkok 10900, Thailand
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Bucko T, Hafner J, Benco L. Adsorption and Vibrational Spectroscopy of CO on Mordenite: Ab initio Density-Functional Study. J Phys Chem B 2005; 109:7345-57. [PMID: 16851841 DOI: 10.1021/jp050151u] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a periodic density-functional investigation of the adsorption and the vibrational spectroscopy of CO in mordenite. Our results highlight a pronounced sensitivity of the strength of the hydrogen bond between the acidic hydroxyl groups and the adsorbed molecule, and hence of the induced red shift of the OH, and the blue shift of the CO stretching mode on the choice of the exchange-correlation functional. The popular Perdew-Wang (PW) gradient-corrected functional strongly overestimates the frequency shifts and the interaction energies. We demonstrate that the revised Perdew-Burke-Ernzerhof (RPBE) functional leads to an improved description of hydrogen bonding. For bridging OH groups, terminal silanol groups and for Lewis sites formed by tricoordinated Al atoms, we predict adsorption energies and frequency shifts in good agreement with experiment. The calculated difference in the binding energies of CO in purely siliceous mordenite and at Brønsted acid sites in the main channel agrees very well with microcalorimetry data. We find that Brønsted acid sites in the small channels (the side-pockets) of mordenite do not adsorb CO, which is adsorbed only in the main channel via the C atom. For these adsorption complexes we find reasonable (though not perfect) agreement of the predicted blue shift of the CO-mode and of the red shift of the OH-mode with experiment. Our prediction that the side-pockets are inaccessible to CO correlates well with the microcalorimetric studies and with experimental observation of the adsorption of O(2), N(2) and H(2) molecules but contradicts the current interpretation of experimental adsorption studies for CO.
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Affiliation(s)
- T Bucko
- Institut für Materialphysik and Center for Computational Material Science, Universität Wien, Sensengasse, A-1090 Wien, Austria.
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The adsorption of benzene on industrially important nanostructured catalysts (H-BEA, H-ZSM-5, and H-FAU): confinement effects. J Mol Struct 2005. [DOI: 10.1016/j.molstruc.2004.09.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Density functional theory study of the ethylene epoxidation over Ti-substituted silicalite (TS-1). ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s1381-1169(03)00473-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Deka RC, Ajitha D, Hirao K. Adsorption of Small Molecules in Zeolites: A Local Hard−Soft Acid−Base Approach. J Phys Chem B 2003. [DOI: 10.1021/jp034311i] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ramesh Ch. Deka
- Department of Chemical Sciences, Tezpur University, Napaam, Tezpur 784 028, India, and Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - D. Ajitha
- Department of Chemical Sciences, Tezpur University, Napaam, Tezpur 784 028, India, and Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kimihiko Hirao
- Department of Chemical Sciences, Tezpur University, Napaam, Tezpur 784 028, India, and Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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The influence of the framework on adsorption properties of ethylene/H-ZSM-5 system: an ONIOM study. J Mol Struct 2003. [DOI: 10.1016/s0022-2860(03)00154-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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