التفاصيل البيبلوغرافية
| العنوان: |
Computational Investigation of Site-Dependent Activation Barriers of Zeolite-Catalyzed Protolytic Cracking Reactions |
| المؤلفون: |
Shubham Malviya (14251379), Peng Bai (220785) |
| سنة النشر: |
2022 |
| مصطلحات موضوعية: |
Biophysics, Biochemistry, Infectious Diseases, Computational Biology, Environmental Sciences not elsewhere classified, Biological Sciences not elsewhere classified, Chemical Sciences not elsewhere classified, Physical Sciences not elsewhere classified, Information Systems not elsewhere classified, noncovalent interactions exerted, level shape selectivity, catalyst pore walls, specific barriers show, ts entropy via, lower ts energies, computational procedure consisting, dependent activation barriers, similar across zeolites, averaged activation barriers, ts configurations adapt, dependent ts energetics, accessible ts configurations, much larger number, complexes using force, approach allows us, averaged barriers, ts configurations, dependent reactivity, computational investigation, exchanged zeolites |
| الوصف: |
Proton-exchanged zeolites are effective Brønsted-acid catalysts that exhibit molecular-level shape selectivity. Yet, the nonuniform, heterogeneous porous environment makes it challenging to understand and predict site-dependent reactivity that originates from the intricate, noncovalent interactions exerted by the catalyst pore walls, especially with large, flexible reactants. In this work, we developed a computational procedure consisting of generating quasi-transition-state (TS) complexes using force-field-based configurational-biased sampling and subsequent reaction path optimization using a density-functional theory-based nudged-elastic-band method. This approach allows us to capture how the TS configurations adapt to the local environment and to obtain a rough estimate of TS entropy via the number of accessible TS configurations at each active site. The resulting site-dependent TS energetics further enable the calculation of ensemble-averaged activation barriers. Using this approach, we studied the protolytic cracking of n -butane in TON, MFI, LTA, and FAU zeolites. It is found that in the MFI zeolite, while the tighter zig-zag and straight channels have lower TS energies, the more spacious intersection region potentially supports a much larger number of TS configurations. In addition, it is also found that if the reactant state is restricted to the vicinity of an active site, the computed site-specific barriers show a large variation across different zeolites and among different sites within the same zeolite, with values ranging from 182 to 218 kJ/mol. We argued that for kinetics-limited reactions, the reactant state should be taken to be the globally most stable configuration and showed that this treatment leads to ensemble-averaged barriers that are substantially more similar across zeolites, with the FAU and LTA zeolites having intrinsic barriers around 220 kJ/mol and the MFI and TON zeolites around 200 kJ/mol. |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
unknown |
| Relation: |
https://figshare.com/articles/journal_contribution/Computational_Investigation_of_Site-Dependent_Activation_Barriers_of_Zeolite-Catalyzed_Protolytic_Cracking_Reactions/21717125 |
| DOI: |
10.1021/acscatal.2c04192.s001 |
| الاتاحة: |
https://doi.org/10.1021/acscatal.2c04192.s001 |
| Rights: |
CC BY-NC 4.0 |
| رقم الانضمام: |
edsbas.F95FF43A |
| قاعدة البيانات: |
BASE |