Substituent effects on the rate of dehydrogenation of primary and secondary alcohols

Gulková, Daniela; Kraus, M.

doi:10.1016/0304-5102(93)e0217-5

Cited by 19 publications

(17 citation statements)

References 10 publications

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“…The use of substituent effects is broadly applicable and can be a valuable tool for expanding the scope of our understanding of catalytic processes. [7][8][9] The work presented in this paper expands on a previous study of the nature of the transition state for carboxylic acid deprotonation on Ag single-crystal surfaces. 10 That work examined the surface chemistry of CH 3 CO 2 H and CF 3 CO 2 H on Ag(111) and Ag(110) surfaces.…”

Section: Introductionmentioning

confidence: 63%

The Transition State for Carboxylic Acid Deprotonation on Cu(100)

Immaraporn

Gellman

2004

J. Phys. Chem. B

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The kinetics of acid deprotonation on the Cu(100) surface have been studied using four different fluorinated carboxylic acids (CF2HCO2H, CF3CO2H, CF2HCF2CO2H, and CF3CF2CO2H). All four acids adsorb molecularly on Cu(100) at 90 K but deprotonate during heating to form carboxylates on the surface at temperatures below 300 K. Temperature-programmed reaction spectroscopy and X-ray photoemission spectroscopy were used to verify that the acids deprotonate on the Cu(100) surface. Work function measurements were used to study the deprotonation kinetics during heating and to estimate the activation energy barriers ( ) to deprotonation. The nature of the transition state to acid deprotonation on Cu(100) was probed by analysis of linear free energy relationships (LFER) or correlations of with the acid substituent constants, σF. The field reaction constant, ρF, or the slope of the LFER was found to be ρF = −52 ± 13 kJ/mol in the limit of zero coverage and ρF = −19 ± 2 kJ/mol at a coverage of 1/2 ML. These values of ρF can be compared to the value of ρF = −104 kJ/mol for acid deprotonation in the gas phase. This comparison suggests that the transition state for acid deprotonation on Cu(100) must be anionic with respect to the reactant (RCO2H(ad) ↔ [RCO2 δ-···Hδ+]‡ → ).

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Section: Introductionmentioning

confidence: 63%

The Transition State for Carboxylic Acid Deprotonation on Cu(100)

Immaraporn

Gellman

2004

J. Phys. Chem. B

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“…In these studies the Taft parameter was used to correlate the inductive effects of alkyl substituents with the activation barrier for dehydrogenation. It was concluded the transition state involves heterolytic cleavage of the a-C d+ -H bond [17].…”

Section: Introductionmentioning

confidence: 99%

“…This parameter has been extensively used to quantify the electron-donating inductive effect of the alkyl groups on the reaction rate observed in homogeneous organic reaction studies [11]. In heterogeneous reactions, the inductive effect of substituent groups has also been observed, specifically, in dehydrogenation reactions of alkoxides on ZnO-Cr 2 O 3 [17], vanadia supported on ceria and titania [18], and Cu(111) [19,20]. In these studies the Taft parameter was used to correlate the inductive effects of alkyl substituents with the activation barrier for dehydrogenation.…”

Section: Introductionmentioning

confidence: 99%

Inductive Effect of Alkyl Chains on Alcohol Dehydration at Bridge-bonded Oxygen Vacancies of TiO2(110)

et al. 2007

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The activation energies for alkene formation via dehydration of alcohols on bridge-bonded oxygen (BBO) vacancy sites of TiO 2 (110) is found to correlate with the inductive electron donating effect of alcohol alkyl groups as measured by the Taft parameter. Based on this correlation we conclude that the reaction involves a single transition state that undergoes concerted rupture of the C-O bond of the alkoxide and a C-H bond of the alkyl group attached to the b-carbon.

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“…1 depicts the representative TEM micrographs of the three styrene derivative-functionalized Pt nanoparticles. [39][40][41] Of the three styrene derivatives under study, the Taft constant increases in the order of tert-butyl (σ* = −0.30) < methoxy (σ* = + 1.81) < trifluoromethyl (σ* = +2.61). 22 Interestingly, whereas the same "bare" platinum colloids (average core diameter 2.8 ± 0.6 nm) 19 were used prior to styrene functionalization, the eventual nanoparticles were markedly smaller and exhibited a clear variation of the core size.…”

Section: Resultsmentioning

confidence: 99%

Effects of para-substituents of styrene derivatives on their chemical reactivity on platinum nanoparticle surfaces

Chen

Deming

et al. 2016

Nanoscale

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Stable platinum nanoparticles were successfully prepared by the self-assembly of para-substituted styrene derivatives onto the platinum surfaces as a result of platinum-catalyzed dehydrogenation and transformation of the vinyl groups to the acetylene ones, forming platinum-vinylidene/-acetylide interfacial bonds. Transmission electron microscopic measurements showed that the nanoparticles were well dispersed without apparent aggregation, suggesting sufficient protection of the nanoparticles by the organic capping ligands, and the average core diameter was estimated to be 2.0 ± 0.3 nm, 1.3 ± 0.2 nm, and 1.1 ± 0.2 nm for the nanoparticles capped with 4-tert-butylstyrene, 4-methoxystyrene, and 4-(trifluoromethyl)styrene, respectively, as a result of the decreasing rate of dehydrogenation with the increasing Taft (polar) constant of the para-substituents. Importantly, the resulting nanoparticles exhibited unique photoluminescence, where an increase of the Hammett constant of the para-substituents corresponded to a blue-shift of the photoluminescence emission, suggesting an enlargement of the HOMO-LUMO band gap of the nanoparticle-bound acetylene moieties. Furthermore, the resulting nanoparticles exhibited apparent electrocatalytic activity towards oxygen reduction in acidic media, with the best performance among the series of samples observed with the 4-tert-butylstyrene-capped nanoparticles due to an optimal combination of the nanoparticle core size and ligand effects on the bonding interactions between platinum and oxygen species.

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Substituent effects on the rate of dehydrogenation of primary and secondary alcohols

Cited by 19 publications

References 10 publications

The Transition State for Carboxylic Acid Deprotonation on Cu(100)

The Transition State for Carboxylic Acid Deprotonation on Cu(100)

Inductive Effect of Alkyl Chains on Alcohol Dehydration at Bridge-bonded Oxygen Vacancies of TiO2(110)

Effects of para-substituents of styrene derivatives on their chemical reactivity on platinum nanoparticle surfaces

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