Guaiacol Hydrodeoxygenation Mechanism on Pt(111): Insights from Density Functional Theory and Linear Free Energy Relations

The reaction mechanism of the mild hydrogenation of guaiacol over Pt(111) has been investigated by density functional theory calculations and microkinetic modeling.Our model suggests that at 573 K catechol is the preferred reaction product and that any deoxygenation to, e.g., phenol or benzene is at least four orders of magnitude slower than the production of catechol.Slow deoxygenation of guaiacol can occur by decarbonylation and possibly by hydrogenation of the phenyl ring followed by C-OH bond cleavage. Direct -OH removal without activation of the phenyl ring is found to be at least five orders of magnitude slower. Overall, this study suggests that Pt (111) sites are not active deoxygenation sites and that the experimentally observed deoxygenation activity of Pt catalysts originates likely from the involvement of the catalyst support or Pt step and corner sites.

show abstract

“…21 Overall, their DFT results are very similar to our results; however, no microkinetic analysis has been performed by these authors.…”

Section: Introductionsupporting

confidence: 92%

Theoretical Investigation of the Reaction Mechanism of the Guaiacol Hydrogenation over a Pt(111) Catalyst

et al. 2015

View full text Add to dashboard Cite

show abstract

“…It should be noted that the isomerization and transalkylation products were included with the unconverted m ‐cresol, as these reactions are catalyzed by BAS without the participation of Pt . The plots yield an apparent activation energy ( E a ) for the DDO path of 49.7 kJ mol −1 , significantly lower than that obtained on Pt(1 1 1) surfaces through theoretical calculations . This relatively low activation energy could be a result of the participation of BAS in the Pt‐catalyzed direct deoxygenation reaction, as suggested in previous work .…”

Section: Discussionmentioning

confidence: 92%

Insights into the Major Reaction Pathways of Vapor‐Phase Hydrodeoxygenation of m‐Cresol on a Pt/HBeta Catalyst

et al. 2016

View full text Add to dashboard Cite

Conversion of m‐cresol was studied on a Pt/HBeta catalyst at 225–350 °C and ambient hydrogen pressure. At 250 °C, the reaction proceeds through two major reaction pathways: (1) direct deoxygenation to toluene (DDO path); (2) hydrogenation of m‐cresol to methylcyclohexanone and methylcyclohexanol on Pt, followed by fast dehydration on Brønsted acid sites (BAS) to methylcyclohexene, which is either hydrogenated to methylcyclohexane on Pt or ring‐contracted to dimethylcyclopentanes and ethylcyclopentane on BAS (HYD path). The initial hydrogenation is the rate‐determining step of the HYD path as its rate is significantly lower than those of subsequent steps. The apparent activation energy of the DDO path is 49.7 kJ mol−1 but the activation energy is negative for the HYD path. Therefore, higher temperatures lead to the DDO path becoming the dominant path to toluene, whereas the HYD path, followed by fast equilibration to toluene, is less dominant, owing to the inhibition of the initial hydrogenation of m‐cresol.

show abstract

“…In addition to kinetic studies, also adsorption studies [48], theoretical DFT (density function theory) calculations [22,[71][72][73][74][75] and bond dissociation energy calculations [36] have been performed.…”

Section: Reaction Pathways and The Thermodynamic Feasibility Of Diffementioning

confidence: 99%

Hydrodeoxygenation of Lignin-Derived Phenols: From Fundamental Studies towards Industrial Applications

Mäki‐Arvela

Murzin

2017

Catalysts

View full text Add to dashboard Cite

Hydrodeoxygenation (HDO) of bio-oils, lignin and their model compounds is summarized in this review. The main emphasis is put on elucidating the reaction network, catalyst stability and time-on-stream behavior, in order to better understand the prerequisite for industrial utilization of biomass in HDO to produce fuels and chemicals. The results have shown that more oxygenated feedstock, selection of temperature and pressure as well as presence of certain catalyst poisons or co-feed have a prominent role in the HDO of real biomass. Theoretical considerations, such as density function theory (DFT) calculations, were also considered, giving scientific background for the further development of HDO of real biomass.

show abstract

Guaiacol Hydrodeoxygenation Mechanism on Pt(111): Insights from Density Functional Theory and Linear Free Energy Relations

Cited by 118 publications

References 53 publications

Theoretical Investigation of the Reaction Mechanism of the Guaiacol Hydrogenation over a Pt(111) Catalyst

Theoretical Investigation of the Reaction Mechanism of the Guaiacol Hydrogenation over a Pt(111) Catalyst

Insights into the Major Reaction Pathways of Vapor‐Phase Hydrodeoxygenation of m‐Cresol on a Pt/HBeta Catalyst

Hydrodeoxygenation of Lignin-Derived Phenols: From Fundamental Studies towards Industrial Applications

Contact Info

Product

Resources

About