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Preprint . 2026
License: CC BY
Data sources: Datacite
ZENODO
Preprint . 2026
License: CC BY
Data sources: Datacite
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Operator Firing Order as the Missing Mechanism in Ethanol-to-Hydrocarbon Selectivity: Contact-Geometric Analysis of ZSM-5 and MCM-22 Zeolites

Authors: Nogueira Grossi, Pablo;

Operator Firing Order as the Missing Mechanism in Ethanol-to-Hydrocarbon Selectivity: Contact-Geometric Analysis of ZSM-5 and MCM-22 Zeolites

Abstract

Zeolite shape selectivity is conventionally attributed to pore size, yet Sousa et al. [8, 9] demonstrated that HZSM-5 and HMCM-22 exhibit reversed product distribu-tions despite similar Brønsted acidity an empirical contrast that pore-size argu-ments alone cannot explain. We show that this reversal arises from a dierence in operator ring order : in ZSM-5, the pore aperture constrains the reaction trajec-tory before molecular branching occurs (C → K → F → U), whereas in MCM-22, molecules enter the large supercage (inner free diameter 7.1 Å [20]) and branch beforeencountering the 10-ring exit lter (C → F → K → U). We formalise this withinthe TO/TOGT framework, which maps heterogeneous catalysis onto a contact 3-manifold Xcat = (R3, αcat) acted on by the operator pipeline G = U ◦ F ◦ K ◦ C.The central result the Helical Selectivity Principle (Theorem 3) establishesthat only reaction pathways with radial coordinate r ≤ r∗(λ) = pJ/λ can reach the stable catalytic xed point x∗, where J is inter-site coupling and λ is the on-sitebinding energy modelled by the Discrete Nonlinear Schrödinger (DNLS) equation[10]. This geometric inequality recovers the empirical pore cut-o of HZSM-5 and HMCM-22, the PtSn ensemble eect, and the trilobe/tetralobe extrudate optimi-sation as corollaries. Four falsiable predictions are stated; Falsiable Prediction 4 reversal of the DRIFTS surface-intermediate sequence in MCM-22 under alteredtemperature or feed conditions is the primary experimental test. Parts (i)(ii) ofthe central theorem are a proof sketch; the Global Contactomorphism Conjecture isstated precisely and not claimed. Lean 4 formalisation (CatGT_Main.lean): 6 closedtheorems, 3 honest admits, 0 hidden sorries. Attached: 1. zeolite_operator_selectivity_FINAL.pdf ← Main paper 2. dm3_zeolite_figures.pdf ← Figures 3. ALGEBRAIC_PROOFS_ALL_7_THEOREMS.md ← Supplementary proofs 4. dm3_dnls_zeolite_simulation.py ← Reproducible code 5. ZENODO_README.md ← Documentation 6. CatGT_PROOFS_COMPLETE.lean ← Formal verification 7. dm3_zeolite_figures.png ← Alt format (optional)

Keywords

operator order,, ethanol-to-hydrocarbon conversion,, Topographical Orthogenetic Theory, DRIFTS,, pore topology,, MCM-22,, contact geometry,, coke formation,, ZSM-5,, Catalysis Today,

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
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Average
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