Theoretical study of the structural, vibrational, and topologic properties of the charge distribution of the molecular complexes between thiophene and Brönsted acid sites of zeolites

Soscún, Humberto; Castellano, Olga; Hernández, Javier; Hinchliffe, Alan

doi:10.1002/qua.1087

Cited by 4 publications

(5 citation statements)

References 21 publications

(30 reference statements)

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“…For instance, the electron correlation reduces the length of this bond by 7.3%, indicating that these effects are very important in sulfur−zeolitemolecular complexes. The comparison of the S 44 −H 43 bond distance with other results of similar complexes from Table indicate that the CH 3 SH-T1O−OH interaction is larger than the interaction of CH 3 SH with the B2 cluster, CH 3 SH with the B3 cluster, and CH 3 SH with the B4 cluster 18 (B2, B3 and B4, are zeolite clusters with 3, 4, and 5 tetrahedrals, respectively) and thiophene with B2 zeolite . These results show that T10 gives a better representation of the zeolite structure and is able to give a more realistic description of the interaction of zeolites with sulfur compounds than zeolite clusters of smaller sizes.…”

Section: Resultssupporting

confidence: 50%

“…These structures were fully optimized following C s symmetry. In addition, the present results were compared with previous calculations of the interaction of CH 3 SH with small zeolite clusters and with those of the thiophene−zeolite interaction reported by us . The structures of the isolated CH 3 SH and CH 3 OH molecules were previously fully optimized.…”

Section: Theoretical Methods and Computational Detailsmentioning

confidence: 84%

“…Topology of the Charge Distribution. Details of the theory associated with the topology of the charge distributions ρ( r ) and their applications to the study of chemical interactions and the formation of zeolite−sulfur complexes has been referenced elsewhere . This theory defines the existence of the bond critical point in the regions where the gradient field of ρ( r ) vanishes (∇ρ( r ) = 0).…”

Section: Resultsmentioning

confidence: 99%

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Adsorption of CH₃SH in Acidic Zeolites: A Theoretical Study

2004

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The adsorption of a CH 3 SH molecule on acid zeolite has been investigated by theoretical ab initio and density functional theory DFT methods. The zeolite was modeled by a cluster of 10 membered rings whose formula is (SiH 2 ) 9 (O) 9 Al(OH) 2 containing 43 atoms and only one Bro ¨nsted acid site (T10-OH). The calculations were performed at Hartree-Fock and the BLYP/DFT levels of theory with the 6-31+G(d,p) basis set and taking the C s symmetry restriction for the isolated species and the adsorption complex geometry. After interaction of CH 3 SH with the zeolite cluster, a van der Waals 1:1 adsorption complex CH 3 SH-T10-OH is formed, with a geometry that is dominated by the formation of a hydrogen bond between the S atom of CH 3 SH and the H atom of the hydroxyl group S--H of the T10-OH moiety. Similar calculations were carried out for the adsorption of methanol CH 3 OH with the T10-OH cluster for comparison. For both complexes the structural, energetic, vibrational, and topologic properties were analyzed. Additionally, the deprotonation energy for the T10-OH cluster was determined and our BLYP value of 1374 kJ/mol is comparable to previous experimental and theoretical determinations from the literature. The structural results indicate that the complex is linear and the interaction energies indicate that the adsorption of the sulfur compound is much less than the oxygenated alcohol, which may be accounted for by the differences in the electronegativities of S and O atoms. A comparison of the calculated interaction energy for the CH 3 SH-T10-OH complex indicates that the nature of CH 3 SH adsorption is similar to other sulfur-zeolite complexes from the literature. The frequency shifts of the OH vibrational mode of the zeolite are found to be negative on complex formation and resemble the corresponding shifts of the experimental adsorption of CH 3 SH in SiO 2 and H-ZSM5 zeolites. Finally, the analysis of the topologic properties of the complexes and the isolated molecules indicate that additional chemical interactions occur between the O atoms of the zeolite network and the H atoms of the CH 3 SH and CH 3 OH molecules, which increases the stability of the complexes.

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Section: Resultssupporting

confidence: 50%

Section: Theoretical Methods and Computational Detailsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

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Adsorption of CH₃SH in Acidic Zeolites: A Theoretical Study

2004

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“…The distance of the additional hydrogen bonds is ∼2.72Å, revealing strong hydrogen bonds. The complexation energies on monomer M 4 are similar to previously reported DFT calculations of the adsorption of thiophene on clusters representing zeolites (6.1-10.5 kJ/mol) [65]. Experimental adsorption of DBT, 4-MDBT, and 4,6-DMDBT on activated carbons shows that selectivities towards the problematic compounds 4-MDBT, between 1.28 and 2.3, and 4,6-DMDBT, between 1.96 and 3.50, using DBT as reference [66].…”

Section: Complexation Energies and Selectivities Of Dbt 4-mdbt And supporting

confidence: 86%

Interaction of Refractory Dibenzothiophenes and Polymerizable Structures

Rivera

Navarro-Santos

Guerra-González

et al. 2014

International Journal of Polymer Science

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We carried out first principles calculations to show that polymerizable structures containing hydroxyl (alcoholic chain) and amino groups are suitable to form stable complexes with dibenzothiophene (DBT) and its alkyl derivates. These sulfur pollutants are very difficult to eliminate through traditional catalytic processes. Spontaneous and exothermic interactions at 0 K primarily occur through the formation of stable complexes of organosulfur molecules with monomeric structures by hydrogen bonds. The bonds are formed between the sulfur atom and the hydrogen of the hydroxyl group; additional hydrogen bonds are formed between the hydrogen atoms of the organosulfur molecule and the nitrogen atoms of the monomers. We vary the number of methylene groups in the alcoholic chain containing the hydroxyl group of the monomer and find that the monomeric structure with four methylene groups has the best selectivity towards the interaction with the methyl derivates with reference to the interaction with DBT. Even this study does not consider solvent and competitive adsorption effects; our results show that monomeric structures containing amino and hydroxyl groups can be used to develop adsorbents to eliminate organosulfur pollutants from oil and its derivates.

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“…The reason to choose these compounds is that THT, TBM, and DMS (selected from alkyl-thiophenes, thiols, and sulfides) are widely used sulfur odorants for light hydrocarbon fuels that are a cost-effective H 2 source for fuel cells, while CO 2 , H 2 O, H 2 S, and COS are common impurities. Several previous calculation studies on adsorption of individual sulfur species (thiophene, , CH 3 SH, , C 2 H 5 SH, H 2 S) as well as light hydrocarbons, − H 2 O, and CO 2 on zeolites can be found in the literature, but their diverse cluster models and levels in the theories taken for the calculations limit a direct and meaningful comparison of the results. Here we present the binding energies of the compounds on simple zeolite model clusters obtained with highly accurate B3LYP and MP2 methods, and discuss the results comparing with experimental sulfur adsorption uptake and selectivity properties of AgNaY zeolites.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Properties of Organosulfur Compounds on Zeolite Clusters: A Density Functional Theory Calculation Study

et al. 2008

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The effects of cations of zeolite for the adsorption of organosulfur compounds were investigated by using density functional theory calculations. The binding energies of tetrahydrothiophene (C 4 H 8 S, THT), dimethyl sulfide (C 2 H 6 S, DMS), tert-butylmercaptan (C 4 H 10 S, TBM), hydrogen sulfide (H 2 S), and carbonyl sulfide (COS) on the zeolite model clusters [X(HO) 3 SiOAl(OH) 3 , X ) H + , Na + and Ag + ] were obtained and compared with those of H 2 O, CO 2 , and C 1 -C 3 light hydrocarbons. Compared to the H + and Na + cations, the Ag + cation induces much stronger binding of THT, DMS, TBM, and H 2 S over H 2 O suggesting great enhancements in the adsorption selectivity. The order of binding energies of these sulfur compounds is THT > DMS > TBM > H 2 S > COS, and it does not depend on the cation types. These results agree well with the experimental adsorption uptake and selectivity properties of AgNaY zeolites for organosulfur compounds.

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Theoretical study of the structural, vibrational, and topologic properties of the charge distribution of the molecular complexes between thiophene and Brönsted acid sites of zeolites

Cited by 4 publications

References 21 publications

Adsorption of CH₃SH in Acidic Zeolites: A Theoretical Study

Adsorption of CH₃SH in Acidic Zeolites: A Theoretical Study

Interaction of Refractory Dibenzothiophenes and Polymerizable Structures

Adsorption Properties of Organosulfur Compounds on Zeolite Clusters: A Density Functional Theory Calculation Study

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Theoretical study of the structural, vibrational, and topologic properties of the charge distribution of the molecular complexes between thiophene and Brönsted acid sites of zeolites

Cited by 4 publications

References 21 publications

Adsorption of CH3SH in Acidic Zeolites: A Theoretical Study

Adsorption of CH3SH in Acidic Zeolites: A Theoretical Study

Interaction of Refractory Dibenzothiophenes and Polymerizable Structures

Adsorption Properties of Organosulfur Compounds on Zeolite Clusters: A Density Functional Theory Calculation Study

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Adsorption of CH₃SH in Acidic Zeolites: A Theoretical Study

Adsorption of CH₃SH in Acidic Zeolites: A Theoretical Study