The dehydration of alcohols

Knözinger, Helmut

doi:10.1002/9780470771259.ch12

Cited by 20 publications

(7 citation statements)

References 198 publications

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“…As shown in Table 1, a hydrogen/deuterium isotope effect was observed using perdeuterated ethanol for both acetaldehyde and ethylene formation, which we attribute to a primary kinetic isotope effect (KIE). Notably, there is also a small hydrogen/ deuterium isotope effect when using ethanol-OD for acetaldehyde production, which could be an equilibrium isotope effect, or as discussed by Knozinger and Scheglila 53 and Bauer, 54 the value of this isotope effect represents the minimum KIE that would be expected in the limit of the high temperatures used in our reactions.…”

Section: Resultsmentioning

confidence: 76%

Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO₂

et al. 2020

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The Mg-catalyzed dehydrogenation of ethanol to yield acetaldehyde is an important step in the Lebedev reaction. In this work, we prepared a model MgO−SiO 2 catalyst by impregnation of MgO onto an SBA-15 support and used this material to study the reaction kinetics of ethanol dehydrogenation to acetaldehyde. The rates of acetaldehyde and ethylene production were measured for ethanol partial pressures ranging from 0.92 to 5.25 kPa. Both rates are fractional order at 723 K, decreasing to nearly zero-order at 648 K. Consistent with the literature for MgO−SiO 2 Lebedev catalysts, both basic sites and Lewis acidic sites were observed on this catalyst. The rates of both acetaldehyde and ethylene were inhibited by pyridine but not by 2,6-ditertbutylpyridine, suggesting that both reactions involve not only basic but also Lewis acidic sites. To elucidate the origin of this cooperativity, a microkinetic model was constructed using a recently published mechanism for the Lebedev reaction catalyzed by MgO. The model was fit to our data using four fitting parameters. The fitting suggests that adsorbed ethanol and hydrogen atoms have a weaker bond with mixed-oxide MgO−SiO 2 catalysts than with bulk MgO catalysts, which we attribute experimentally to an increase in the number of moderate-strength Mg 2+ − O 2− site pairs formed at the expense of strongly basic MgO sites.

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Section: Resultsmentioning

confidence: 76%

Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO₂

et al. 2020

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“…Dehydration of alcohols to olefins or ethers is known to be catalyzed by metal oxides . Alumina has been extensively studied for this reaction .…”

Section: Introductionmentioning

confidence: 99%

“…Dehydration of alcohols to olefins or ethers is known to be catalyzed by metal oxides . Alumina has been extensively studied for this reaction . Other oxides such as ZrO 2 and rare earth oxides have been examined as well.…”

Section: Introductionmentioning

confidence: 99%

Dehydration of 2‐Octanol over Ca‐doped CeO₂ Catalysts

et al. 2017

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Vapor‐phase catalytic dehydration of 2‐octanol was investigated over Ca‐doped CeO2 at 375 °C and atmospheric pressure. Ca doping up to 0.15 wt % was found to increase the dehydration activity for 2‐octanol, whereas further increases in Ca content (0.50 and 1.25 wt %) detrimentally affected the conversion. Catalyst surface area and pore volume increased with increasing Ca content in Ca‐doped CeO2. Hydrogen temperature‐programmed reduction (TPR) profiles indicate that the partially reduced state of surface ceria (i.e., Ce3+), which increases with increasing Ca loading up to 0.15 wt %, might play an important role in promoting dehydration.

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“…The dehydration of alcohols has been investigated over a wide spectrum of solid acid catalysts in both the vapor phase and the liquid phase. 5 With the exception of methanol, the dehydration of an aliphatic alcohol proceeds via two pathways, i.e., the intermolecular dehydration to ethers and the intramolecular dehydration to alkenes. 6 Ether formation is favored at lower reaction temperatures, whereas alkenes are the preferred products at higher temperatures.…”

Section: ■ Introductionmentioning

confidence: 99%

Dehydration of 1-Octadecanol over H-BEA: A Combined Experimental and Computational Study

et al. 2016

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Liquid-phase dehydration of 1-octadecanol, which is intermediately formed during the hydrodeoxygenation of microalgae oil on zeolite H-BEA, has been studied, combining experiment and theory. Both the OH group and the alkyl chain of 1-octadecanol interact with zeolite Brønsted acid sites, inducing inefficient utilization in the presence of high acid-site concentrations. The parallel intramolecular and intermolecular dehydration pathways, leading to octadecene and dioctadecyl ether, have different activation energies and pass through different reaction intermediates. The formation of surface alkoxides is the rate-limiting step in the intramolecular dehydration, whereas the intermolecular dehydration proceeds via a bulky dimer intermediate, occurring preferentially at the pore mouth or outer surface of zeolite crystallites. Despite the main contribution of Brønsted acid sites toward both dehydration pathways, Lewis acid sites are also active to form dioctadecyl ether.

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The dehydration of alcohols

Cited by 20 publications

References 198 publications

Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO₂

Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO₂

Dehydration of 2‐Octanol over Ca‐doped CeO₂ Catalysts

Dehydration of 1-Octadecanol over H-BEA: A Combined Experimental and Computational Study

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The dehydration of alcohols

Cited by 20 publications

References 198 publications

Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO2

Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO2

Dehydration of 2‐Octanol over Ca‐doped CeO2 Catalysts

Dehydration of 1-Octadecanol over H-BEA: A Combined Experimental and Computational Study

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Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO₂

Reaction Kinetics Analysis of Ethanol Dehydrogenation Catalyzed by MgO–SiO₂

Dehydration of 2‐Octanol over Ca‐doped CeO₂ Catalysts