scholarly journals Sulfur Resistance of Pt-W Catalysts

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Carolina P. Betti ◽  
Juan M. Badano ◽  
Ivana L. Rivas ◽  
Vanina A. Mazzieri ◽  
M. Juliana Maccarrone ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Model Compound ◽  
Pt Catalysts ◽  
Electronic Effects ◽  
Sulfur Resistance ◽  
Metal Impregnation

The sulfur resistance of low-loaded monometallic Pt catalysts and bimetallic Pt-W catalysts during the partial selective hydrogenation of styrene, a model compound of Pygas streams, was studied. The effect of metal impregnation sequence on the activity and selectivity was also evaluated. Catalysts were characterized by ICP, TPR, XRD, and XPS techniques. Catalytic tests with sulfur-free and sulfur-doped feeds were performed. All catalysts showed high selectivities (>98%) to ethylbenzene. Activity differences between the catalysts were mainly attributed to electronic effects due to the presence of different electron-rich species of Pt0and electron-deficient species ofPtδ+. Pt0promotes the cleavage of H2whilePtδ+the adsorption of styrene. The catalyst successively impregnated with W and Pt (WPt/Al) was more active and sulfur resistant than the catalyst prepared with an inverse impregnation order (PtW/Al). The higher poison resistance of WPt/Al was attributed to both steric and electronic effects.

The structure and electronic effects of ZIF-8 and ZIF-67 supported Pt catalysts for crotonaldehyde selective hydrogenation

2022 ◽  
Author(s):  
Haiyu Shen ◽  
Huahua Zhao ◽  
Jian Yang ◽  
Jun Zhao ◽  
Liang Yan ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Selective Hydrogenation ◽  
Metal Organic Frameworks ◽  
Pt Catalysts ◽  
Electronic Effects ◽  
Supported Pt Catalysts ◽  
Metal Organic

Metal organic frameworks (MOFs) have been applied to stabilize metal nanoparticles due to their excellent properties, but there are many different viewpoints about the interaction between MOF and nanoparticles, which...

scholarly journals Effect of Carbon Supported Pt Catalysts on Selective Hydrogenation of Cinnamaldehyde

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Qing Han ◽  
Yunfei Liu ◽  
Dong Wang ◽  
Fulong Yuan ◽  
Xiaoyu Niu ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Impregnation Method ◽  
Pt Catalysts ◽  
Cinnamyl Alcohol ◽  
Electronic Effects ◽  
Carbon Supports ◽  
Graphene Oxides ◽  
Graphitization Degree ◽  
Supported Pt Catalysts ◽  
Reduced Graphene

Selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) is of both fundamental and industrial interest. It is of great significance to evaluate the possible differences between different supports arising from metal dispersion and electronic effects, in terms of activity and selectivity. Herein, Pt catalysts on different carbon supports including carbon nanotubes (CNTs) and reduced graphene oxides (RGO) were developed by a simple wet impregnation method. The resultant catalysts were well characterized by XRD, Raman, N2physisorption, TEM, and XPS analysis. Applied in the hydrogenation of cinnamaldehyde, 3.5 wt% Pt/CNT shows much higher selectivity towards cinnamyl alcohol (62%) than 3.5 wt% Pt/RGO@SiO2(48%). The enhanced activity can be ascribed to the high graphitization degree of CNTs and high density of dispersed Pt electron cloud.

scholarly journals High-Active Metallic-Activated Carbon Catalysts for Selective Hydrogenation

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Nicolás Carrara ◽  
Carolina Betti ◽  
Fernando Coloma-Pascual ◽  
María Cristina Almansa ◽  
Laura Gutierrez ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Selective Hydrogenation ◽  
Nickel Catalysts ◽  
Metallic Phase ◽  
Hydrogen Chemisorption ◽  
Electronic Effects ◽  
X Ray ◽  
Mild Conditions ◽  
Temperature Programmed ◽  
Carbon Catalysts

A series of low-loaded metallic-activated carbon catalysts were evaluated during the selective hydrogenation of a medium-chain alkyne under mild conditions. The catalysts and support were characterized by ICP, hydrogen chemisorption, Raman spectroscopy, temperature-programmed desorption (TPD), temperature-programmed reduction (TPR), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR micro-ATR), transmission electronic microscopy (TEM), and X-ray photoelectronic spectroscopy (XPS). When studying the effect of the metallic phase, the catalysts were active and selective to the alkene synthesis. NiCl/C was the most active and selective catalytic system. Besides, when the precursor salt was evaluated, PdN/C was more active and selective than PdCl/C. Meanwhile, alkyne is present in the reaction media, and geometrical and electronic effects favor alkene desorption and so avoid their overhydrogenation to the alkane. Under mild conditions, nickel catalysts are considerably more active and selective than the Lindlar catalyst.

Selective hydrogenation of 2-pentenal using highly dispersed Pt catalysts supported on ZnSnAl mixed metal oxides derived from layered double hydroxides

2020 ◽  
Vol 10 (4) ◽  
pp. 1106-1116
Author(s):  
Huanjun Wang ◽  
Xiaocheng Lan ◽  
Shiqing Wang ◽  
Babar Ali ◽  
Tiefeng Wang
Keyword(s):  
Metal Oxides ◽  
Layered Double Hydroxides ◽  
Selective Hydrogenation ◽  
High Selectivity ◽  
Mixed Metal Oxides ◽  
Pt Catalysts ◽  
Mixed Metal ◽  
Highly Dispersed ◽  
Double Hydroxides

Highly dispersed Pt catalysts supported on ZnSnAl mixed metal oxides showed high selectivity for 2-pentenol in selective hydrogenation of 2-pentenal.

Selective hydrogenation of cinnamaldehyde to cinnamyl alcohol over BN-supported Pt catalysts at room temperature

2019 ◽  
Vol 578 ◽  
pp. 105-115 ◽  
Author(s):  
Zhang Cao ◽  
Jiahao Bu ◽  
Zeqin Zhong ◽  
Changyong Sun ◽  
Qingsong Zhang ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Room Temperature ◽  
Pt Catalysts ◽  
Cinnamyl Alcohol ◽  
Supported Pt Catalysts

scholarly journals Metal and Precursor Effect during 1-Heptyne Selective Hydrogenation Using an Activated Carbon as Support

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Cecilia R. Lederhos ◽  
Juan M. Badano ◽  
Nicolas Carrara ◽  
Fernando Coloma-Pascual ◽  
M. Cristina Almansa ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Selective Hydrogenation ◽  
Photoelectron Spectroscopy ◽  
Palladium Catalysts ◽  
Active Sites ◽  
Ruthenium Catalysts ◽  
Superior Performance ◽  
Support Surface ◽  
Electronic Effects ◽  
X Ray

Palladium, platinum, and ruthenium supported on activated carbon were used as catalysts for the selective hydrogenation of 1-heptyne, a terminal alkyne. All catalysts were characterized by temperature programmed reduction, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. TPR and XPS suggest that the metal in all catalysts is reduced after the pretreatment with H2at 673 K. The TPR trace of the PdNRX catalyst shows that the support surface groups are greatly modified as a consequence of the use of HNO3during the catalyst preparation. During the hydrogenation of 1-heptyne, both palladium catalysts were more active and selective than the platinum and ruthenium catalysts. The activity order of the catalysts is as follows: PdClRX > PdNRX > PtClRX ≫ RuClRX. This superior performance of PdClRX was attributed in part to the total occupancy of the d electronic levels of the Pd metal that is supposed to promote the rupture of the H2bond during the hydrogenation reaction. The activity differences between PdClRX and PdNRX catalysts could be attributed to a better accessibility of the substrate to the active sites, as a consequence of steric and electronic effects of the superficial support groups. The order for the selectivity to 1-heptene is as follows: PdClRX = PdNRX > RuClRX > PtClRX, and it can be mainly attributed to thermodynamic effects.

Effect of the support, Al2O3 or SiO2, on the catalytic behaviour of Cr–ZnO promoted Pt catalysts in the selective hydrogenation of cinnamaldehyde

2011 ◽  
Vol 402 (1-2) ◽  
pp. 50-58 ◽  
Author(s):  
E.V. Ramos-Fernández ◽  
J. Ruiz-Martínez ◽  
J.C. Serrano-Ruiz ◽  
J. Silvestre-Albero ◽  
A. Sepúlveda-Escribano ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Pt Catalysts ◽  
Catalytic Behaviour ◽  
Effect Of The Support

scholarly journals Electronic and bite angle effects in catalytic C–O bond cleavage of a lignin model compound using ruthenium Xantphos complexes

2017 ◽  
Vol 7 (3) ◽  
pp. 619-626 ◽  
Author(s):  
Luke Shaw ◽  
D. M. Upulani K. Somisara ◽  
Rebecca C. How ◽  
Nicholas J. Westwood ◽  
Pieter C. A. Bruijnincx ◽  
...  
Keyword(s):  
Model Compound ◽  
Bond Cleavage ◽  
Electronic Effects ◽  
Ether Bond ◽  
Lignin Model Compound ◽  
Bite Angle ◽  
Lignin Model ◽  
Ether Bond Cleavage

Bite angle and electronic effects on the ruthenium–diphosphine catalysed ether bond cleavage of the lignin β-O-4 model compound 2-phenoxy-1-phenylethanol were tested.

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