DFT studies of homogeneous catalysis in the gas phase: Dehydration kinetics of several tertiary alcohols with hydrogen chloride

Mora, José R.; Marquez, David J.; Márquez, Edgar; Loroño, Marcos; Córdova, Tania; Chuchani, Gabriel

doi:10.1002/qua.23145

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…Several kinetic investigations have indicated that the formation of ethers through an Ad E 2 mechanism and subsequent ether‐splitting could provide an alternative pathway 19. 20 For the hydrochloric acid‐catalyzed gas phase dehydration, a concerted six‐membered transition‐state has been proposed on the basis of DFT calculations, with the HCl proton linked to the OH group and the chloride linked to the hydrogen atom at the β‐position 21. In the case of alcohol dehydration over γ‐alumina, the mechanism seems different from that of simple Brønsted acids, as the involvement of free carbenium ions, as in the E1 mechanism, can be ruled out on the basis of kinetic isotope effect (KIE) studies.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Insights into the Rhenium‐Catalyzed Alcohol‐To‐Olefin Dehydration Reaction

Korstanje

Jastrzebski

Gebbink

2013

Chemistry A European J

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Rhenium-based complexes are powerful catalysts for the dehydration of various alcohols to the corresponding olefins. Here, we report on both experimental and theoretical (DFT) studies into the mechanism of the rhenium-catalyzed dehydration of alcohols to olefins in general, and the methyltrioxorhenium-catalyzed dehydration of 1-phenylethanol to styrene in particular. The experimental and theoretical studies are in good agreement, both showing the involvement of several proton transfers, and of a carbenium ion intermediate in the catalytic cycle.

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Section: Introductionmentioning

confidence: 99%

Mechanistic Insights into the Rhenium‐Catalyzed Alcohol‐To‐Olefin Dehydration Reaction

Korstanje

Jastrzebski

Gebbink

2013

Chemistry A European J

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“…Recently, Julio et al studied the gas‐phase elimination kinetics of aliphatic unsaturated aldehydes in the presence of hydrogen chloride, showing that the reaction occurs in a homogeneous and molecular manner [8]. Moreover, Mora and coworkers have evaluated the dehydration kinetics of several tertiary alcohols using hydrogen chloride as catalyst [9]. Their results showed that this reaction is molecular in nature and occurs through a six‐membered transition state.…”

Section: Introductionmentioning

confidence: 99%

Unveiling the structure‐reactivity relationship involved in the reaction mechanism of the HCl‐catalyzed alkyl t‐butyl ethers thermal decomposition. A computational study

Cuesta

Mora

Meneses

et al. 2022

Int J of Quantum Chemistry

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The gas‐phase thermal decomposition of a series of alkyl t‐butyl ethers catalyzed by hydrogen chloride is theoretically studied at the ωB97XD/6‐311++g(d)//CCSD(T)/6‐311++g(d) level. The experimental activation free energy for three known systems namely: t‐butyl methyl ether, t‐butyl ethyl ether, and t‐butyl isopropyl ether is used for validation of the proposed theoretical model as the transition state (TS). The chemical process was characterized using intrinsic reaction coordinate, reaction force, and reaction electronic flux profiles. The Cαδ+Oδ− polarization was identified as the determining factor in the rate‐limiting step. Upon functionalization on the Cα, 24 new compounds with different electron‐withdrawing and donating groups were studied. A good multiple‐linear correlation (R2 = 0.88) was found between the Ln(kX/kH) as the response variable and the Taft‐Topsom substituent parameters as attributes. This result supports the reliability and predictability of the proposed transition state model at this level of theory.

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“…By comparing different functional groups the following reactivity was found acid<ester<alco-hol<ether (Stimson & Tilley, 1972). In 2012, Mora et al studied the hydrogen chloride catalyzed dehydration reaction mechanism of several tertiary alcohols (Jose R. Mora et al, 2012); while, in 2015, Julio et al worked on elucidating the gas phase elimination kinetics of aliphatic unsaturated aldehydes catalyzed by hydrogen chloride (Julio, Mora, Maldonado, & Chuchani, 2015). Their results suggest these reactions are homogeneous and unimolecular.…”

Section: Introductionmentioning

confidence: 99%

Gas Phase Decomposition of T-Butyl Methyl Ether Catalyzed by Different Hydrogen Halides: A DFT Study

Cuesta¹,

Mora

Márquez³

2022

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The gas phase decomposition of t-butyl methyl ether catalyzed by hydrogen halides is studied. Four different hydrogen halides (fluorine, chlorine, bromine, and iodine) were evaluated to determine the electronic influence of the halogen in the reaction mechanism. To describe the mechanism, the ωB97XD/LANL2DZ level of theory was used. The reactivity order found was F<Cl<Br<I. Interestingly, the activation free energy estimated for the HCl model was 133.9 kJ/mol, which is in good agreement with the experimental one (134.3 kJ/mol). Furthermore, a correlation above 0.804 was noticed when the electronegativity, the hydrogen-halide distance, and the pKa of the hydrogen halides were compared to the thermodynamic parameters (activation free energy, enthalpy, and entropy). Analyzing the mechanism in depth through the intrinsic reaction coordinate, reaction force, and reaction electronic flux plots, it was observed that though the reaction occurs in a one-step concerted way. The mechanism could be divided into two events; the first one composed by a proton transfer from the halide to the oxygen and the carbon-oxygen bond cleavage, and the second one being the rate-limiting event which includes the proton transfer from the t-butyl to the halide and the double bond formation.

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DFT studies of homogeneous catalysis in the gas phase: Dehydration kinetics of several tertiary alcohols with hydrogen chloride

Cited by 5 publications

References 27 publications

Mechanistic Insights into the Rhenium‐Catalyzed Alcohol‐To‐Olefin Dehydration Reaction

Mechanistic Insights into the Rhenium‐Catalyzed Alcohol‐To‐Olefin Dehydration Reaction

Unveiling the structure‐reactivity relationship involved in the reaction mechanism of the HCl‐catalyzed alkyl t‐butyl ethers thermal decomposition. A computational study

Gas Phase Decomposition of T-Butyl Methyl Ether Catalyzed by Different Hydrogen Halides: A DFT Study

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