Trends in C2−C4 Alcohols Dehydration Catalyzed by the γ‐Alumina (100) Surface: The Isobutanol Puzzle
Abstract
The monomolecular dehydration of alcohols into olefins catalyzed by the (100) surface of γ‐alumina is investigated by DFT simulations. The transition states (TS) and mean energy paths are determined for C2 to C4 alcohols through the intrinsic reaction coordinate (IRC) method. The reaction occurs through a non‐ideal E2‐type mechanism: the Cα─O bond stretching takes place before the Cβ─Hβ stretching along IRC. Quantitative structural and energetic trends are recovered: primary alcohols are the least reactive with the lower (respectively larger) Cα─O (respectively Cβ─Hβ) stretching, while secondary and tertiary are the most reactive with the larger (respectively lower) Cα─O (respectively Cβ─Hβ) stretching. However, the calculated dehydration kinetic constant of isobutanol underestimates the experimental one. By analyzing structural and charge descriptors along the IRC path and at TS, we identify that the TS of isobutanol dehydration is subject to steric hindrance between the two methyl groups present on and the (100) surface, which destabilizes the TS during the elimination. This destabilization is confirmed by the Bader charge analysis of the TS carbocationic alkyl moiety. We finally question the relevance of the Al site located on the (100) surface for catalyzing the dehydration of alcohols containing hindered mathematical equation atom.
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BibTeX
@article{marmey2026trends,
title = {{Trends in C2−C4 Alcohols Dehydration Catalyzed by the γ‐Alumina (100) Surface: The Isobutanol Puzzle}},
author = {Pierre Marmey and Thomas Pigeon and Manuel Corral Valero and Pascal Raybaud},
journal = {ChemCatChem},
year = {2026},
month = sep,
doi = {10.1002/cctc.71080},
url = {https://ifp.hal.science/hal-05785578v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Trends in C2−C4 Alcohols Dehydration Catalyzed by the γ‐Alumina (100) Surface: The Isobutanol Puzzle
AU - Pierre Marmey
AU - Thomas Pigeon
AU - Manuel Corral Valero
AU - Pascal Raybaud
PY - 2026
DA - 2026/09/30
JO - ChemCatChem
DO - 10.1002/cctc.71080
UR - https://ifp.hal.science/hal-05785578v1
AB - The monomolecular dehydration of alcohols into olefins catalyzed by the (100) surface of γ‐alumina is investigated by DFT simulations. The transition states (TS) and mean energy paths are determined for C2 to C4 alcohols through the intrinsic reaction coordinate (IRC) method. The reaction occurs through a non‐ideal E2‐type mechanism: the Cα─O bond stretching takes place before the Cβ─Hβ stretching along IRC. Quantitative structural and energetic trends are recovered: primary alcohols are the least reactive with the lower (respectively larger) Cα─O (respectively Cβ─Hβ) stretching, while secondary and tertiary are the most reactive with the larger (respectively lower) Cα─O (respectively Cβ─Hβ) stretching. However, the calculated dehydration kinetic constant of isobutanol underestimates the experimental one. By analyzing structural and charge descriptors along the IRC path and at TS, we identify that the TS of isobutanol dehydration is subject to steric hindrance between the two methyl groups present on and the (100) surface, which destabilizes the TS during the elimination. This destabilization is confirmed by the Bader charge analysis of the TS carbocationic alkyl moiety. We finally question the relevance of the Al site located on the (100) surface for catalyzing the dehydration of alcohols containing hindered mathematical equation atom.
SN - 1867-3880
SN - 1867-3899
ER -