Toward an Understanding of Zeolite Y as a Cracking Catalyst with the Use of Periodic Charge Equilibration

Ramachandran, Sunder; Lenz, Terry G.; Skiff, and W. M.; Rappé, Anthony K.

doi:10.1021/jp952864q

Cited by 78 publications

(70 citation statements)

References 83 publications

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“…Also, it was noted that a strong electron delocalization occurred: the limitation of the zeolite catalyst to a molecular fragment is then biased. This is according to Ramachandran et al 53 the main reason why associative reaction mechanisms rather than consecutive reaction mechanisms are usually more likely in zeolite. Of course, one cannot find this when doing quantum chemical calculations employing the cluster approach of these reactions, as the zeolite catalyst cavity is not explicitly considered.…”

Section: Discussionmentioning

confidence: 77%

A Periodic Density Functional Theory Study of Cumene Formation Catalyzed by H-Mordenite

2004

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A periodic density functional theory study of the alkylation of benzene with propene in proton-exchanged mordenite has been achieved. The two different reaction routes that are usually proposed for this reaction, namely the direct and the step-by-step reaction pathways, have been investigated. The explicit consideration of the zeolite catalyst framework allows a better level of description of the interactions between the catalyst framework and the reaction than what is obtained with the cluster approach method. The direct reaction route is found to be the preferred one. It is observed that the cluster approach method, which does not describe the zeolite framework, is unable to qualitatively described the trend in activation energies. This is owing to the greater stabilization of larger transition state by the mordenite zeolite framework compared with smaller ones.

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Section: Discussionmentioning

confidence: 77%

A Periodic Density Functional Theory Study of Cumene Formation Catalyzed by H-Mordenite

2004

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“…Ramachandran et al created the periodic charge equilibration (PQEq) method to derive the charges for periodic systems. 879 They applied the method to systems related to zeolite Y and found that the zeolite lattice has little influence on the charge distributions of absorbed n -octane, water, and benzene, but a considerable effect on the charge distribution of the transition state in the hydride transfer reaction between the C 4 H 9 + ion and n -octane.…”

Section: Classical Modeling Of Metal Ions: the Polarizable Modelmentioning

confidence: 99%

Metal Ion Modeling Using Classical Mechanics

2017

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Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems.

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“…Ramachandran et al extended the original approach to the extended crystals by incorporating the lattice effect in the expression for the chemical potential and called it the periodic charge equilibration method (PQeq). 42 Haldoupis et al adapted these methods for use with MOFs. 12 The charge assignment methods outlined above rely on the assumption that assigning point charges to MOF atoms is sufficient to reproduce the electrostatic interaction relevant to adsorbing molecules.…”

Section: Introductionmentioning

confidence: 99%

Accelerating Applications of Metal–Organic Frameworks for Gas Adsorption and Separation by Computational Screening of Materials

2012

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The selection of metal-organic frameworks (MOFs) for gas adsorption and separation has become a significant challenge over the past decade because of the large number of new structures reported every year. We applied a multiscale computational approach to screen existing MOFs for CO(2)/N(2) separation. Pore characteristics of 1163 MOFs were analyzed by the method developed by Haldoupis, Nair, and Sholl (Haldoupis, E.; Nair, S.; Sholl, D. S. J. Am. Chem. Soc.2010, 132, 7528) using a simple steric model. On the basis of the pore size analysis, 359 MOFs were examined by classical molecular simulations. Adsorption and diffusion properties were computed using grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations, respectively. These molecular simulations were used to assess which materials hold the greatest promise as membrane materials for CO(2)/N(2) separations. Finally, density functional theory (DFT) calculations were performed to provide preliminary information on the dynamic framework motion of selected MOFs.

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Toward an Understanding of Zeolite Y as a Cracking Catalyst with the Use of Periodic Charge Equilibration

Cited by 78 publications

References 83 publications

A Periodic Density Functional Theory Study of Cumene Formation Catalyzed by H-Mordenite

A Periodic Density Functional Theory Study of Cumene Formation Catalyzed by H-Mordenite

Metal Ion Modeling Using Classical Mechanics

Accelerating Applications of Metal–Organic Frameworks for Gas Adsorption and Separation by Computational Screening of Materials

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