Al-Modified Ti-MOR as a robust catalyst for cyclohexanone ammoximation with enhanced anti-corrosion performance

2021 ◽  
Author(s):  
Rusi Peng ◽  
Zhipeng Wan ◽  
Huanzhi Lv ◽  
Yejun Guan ◽  
Hao Xu ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Active Sites ◽  
Corrosion Performance ◽  
Cyclohexanone Ammoximation

The skeleton desilication accompanied by Ti active sites leaching accounts for the dominant chemical deactivation reasons in the alkali liquid-phase ammoximation, which could be retarded by creating a protective Al-rich shell.

scholarly journals Solid-to-liquid phase transitions of sub-nanometer clusters enhance chemical transformation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Juan-Juan Sun ◽  
Jun Cheng
Keyword(s):  
Phase Transitions ◽  
Liquid Phase ◽  
Active Sites ◽  
Catalyst Activity ◽  
Ab Initio Molecular Dynamics ◽  
Free Energies ◽  
Elementary Reactions ◽  
Au Clusters ◽  
Calculate Temperature Dependence ◽  
Entropic Effects

AbstractUnderstanding the nature of active sites is crucial in heterogeneous catalysis, and dynamic changes of catalyst structures during reaction turnover have brought into focus the dynamic nature of active sites. However, much less is known on how the structural dynamics couples with elementary reactions. Here we report an anomalous decrease in reaction free energies and barriers on dynamical sub-nanometer Au clusters. We calculate temperature dependence of free energies using ab initio molecular dynamics, and find significant entropic effects due to solid-to-liquid phase transitions of the Au clusters induced by adsorption of different states along the reaction coordinate. This finding demonstrates that catalyst dynamics can play an important role in catalyst activity.

Active sites in modified copper catalysts for selective liquid phase dehydration of aqueous glycerol to acetol

RSC Advances ◽  
2013 ◽  
Vol 3 (37) ◽  
pp. 16499 ◽  
Author(s):  
Rasika B. Mane ◽  
Aritomo Yamaguchi ◽  
Atul Malawadkar ◽  
Masayuki Shirai ◽  
Chandrashekhar V. Rode
Keyword(s):  
Liquid Phase ◽  
Active Sites ◽  
Copper Catalysts

Active sites for the liquid-phase beckmann rearrangement of cyclohexanone, acetophenone and cyclododecanone oximes, catalyzed by beta zeolites

1998 ◽  
Vol 177 (2) ◽  
pp. 267-272 ◽  
Author(s):  
M CAMBLOR ◽  
A CORMA ◽  
H GARCIA ◽  
V SEMMERHERLEDAN ◽  
S VALENCIA
Keyword(s):  
Liquid Phase ◽  
Active Sites ◽  
Beckmann Rearrangement ◽  
Beta Zeolites

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

2012 ◽  
Vol 550-553 ◽  
pp. 420-423 ◽  
Author(s):  
Qian Wen Dai ◽  
Zi Li Liu ◽  
Cui Xia Xu ◽  
Qi Gang Xie ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Liquid Phase ◽  
Selective Hydrogenation ◽  
Active Sites ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Catalytic Performance ◽  
Chemical Reduction Method ◽  
Ultrasonic Assisted ◽  
Optimal Reaction

The Ni-Mo-P amorphous catalysts were prepared by chemical reduction method under different sonication conditions. The catalytic performance of the prepared catalysts in selective hydrogenation of nitrobenzene(NB) to aniline(AN) were characterized by XRD, BET, N2-adsorption, H2-TPR and H2-TPD. The results show that the introduction of ultrasonic can improve the dispersion of the active sites in the catalyst, the particle size of the catalyst is also smaller than the regular prepared Ni-Mo-P amorphous catalyst. And the influences of the sonication power and time on the catalysts were discussed and compared. The optimal sonication condition is 70 W within 25 min, its optimal reaction time is 150 min.

Hydrogenation of Ethylbenzene Over Ru/γ-Al2O3 Catalyst in Trickle-Bed Reactor

2021 ◽  
Vol 21 (7) ◽  
pp. 4116-4120
Author(s):  
Seung Kyo Oh ◽  
Huiji Ku ◽  
Gi Bo Han ◽  
Byunghun Jeong ◽  
Young-Kwon Park ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Active Sites ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Impregnation Method ◽  
Average Pore ◽  
Wet Impregnation ◽  
Trickle Bed Reactor ◽  
Liquid Phase Hydrogenation ◽  
Trickle Bed

The objective of this study is to evaluate the catalytic performance of pellet-type Ru/γ-Al2O3 as a catalyst during liquid-phase hydrogenation of the aromatic hydrocarbon. The Ru/γ-Al2O3 catalyst was prepared using a wet impregnation method. After adding a binder to Ru/γ-Al2O3, a pellet-type catalyst was obtained through an extrusion method. Nanoporous structures are well developed in the pellet-type Ru/γ-Al2O3 catalyst. The average pore sizes of the Ru/γ-Al2O3 catalysts were approximately 10 nm. The catalytic performance of the pellet-type Ru/γ-Al2O3 catalyst during ethylbenzene hydrogenation was evaluated in a trickle-bed reactor. When the ruthenium loading increased from 1 to 5 wt%, the number of active sites effective for the hydrogenation of ethylbenzene increased proportionally. In order to maximize the conversion of ethylbenzene to ethylcyclohexane, it was necessary to maintain a liquid phase hydrogenation reaction in the trickle bed reactor. In this regards, the reaction temperature should be lower than 90 °C. The conversion of ethylbenzene to ethylcyclohexane on the Ru(5 wt%)/γ-Al2O3 catalyst was highest, which is ascribed to the largest number of active sites of the catalyst.

One methyl group makes a major difference: shape-selective catalysis by zeolite nanoreactors in liquid-phase condensation reactions

2017 ◽  
Vol 5 (33) ◽  
pp. 17464-17469 ◽  
Author(s):  
Chang Liu ◽  
Changyan Cao ◽  
Jian Liu ◽  
Xiaoshi Wang ◽  
Yanan Zhu ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Active Sites ◽  
Knoevenagel Condensation ◽  
Shape Selectivity ◽  
Methyl Group ◽  
Condensation Reactions ◽  
Shape Selective ◽  
Selective Catalysis ◽  
Zeolite Crystals

Shape-selectivity with one-methyl-group-precision can be realized in Knoevenagel condensation reactions on zeolite crystals encapsulating basic active sites.

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