Selective Liquid-Phase Hydrogenation of Citral over Supported Palladium

1997 ◽  
Vol 172 (1) ◽  
pp. 46-54 ◽  
Author(s):  
M.A. Aramendı́a ◽  
V. Borau ◽  
C. Jiménez ◽  
J.M. Marinas ◽  
A. Porras ◽  
...  
1989 ◽  
Vol 54 (11) ◽  
pp. 3003-3010 ◽  
Author(s):  
Jiří Hanika ◽  
Vladimíra Ehlová

Kinetics of the side reactions represented by the system involving hydrogenation and disproportionation of cyclohexene on a commercial catalyst CHEROX 41-00 (3%Pd/C) and on a supported palladium catalyst prepared by impregnation of aluminia with aqueous palladium dichloride (2.15% Pd/γ-Al2O3) have been investigated. As follows from the effectiveness factors of internal diffusion for individual reactions, in the region of internal diffusion, cyclohexene hydrogenation is preferred compared to disproportionation. This finding can be related to the fact that while the rate of disproportionation is controlled by cyclohexene diffusion, the rate of hydrogenation is controlled by diffusion of hydrogen.


Author(s):  
Alexander A. Krasnov ◽  
Adele R. Latypova ◽  
Olga V. Lefedova ◽  
Nikolaiy Yu. Sharonov ◽  
Evgeniy V. Efremov ◽  
...  

A study of the kinetics of liquid phase hydrogenation of nitrobenzene, 4-nitrotoluene, 4-nitroaniline and 2-chloro-4-nitroaniline on supported palladium catalyst in aqueous solutions of 2-propanol of different composition was carried out. The influence of the substituent on the value of the total amount of hydrogen absorbed during the reaction and the kinetics of the hydrogenation of substituted nitrobenzenes was discussed. It was found out that the reaction selectivity to 2-chloro-1,4-phenylenediamine decreases due to by-reaction dehalogenation. The degree of dehalogenation depends on the composition of solvent and may be approximately estimated by the values of the absorbed hydrogen volume during the reaction. Also, the presence of the donor-acceptor substituents is capable of exerting influence on the reaction rate of hydrogenation of the nitro compound.


Author(s):  
Lihui Fan ◽  
Luyang Zhang ◽  
Yanming Shen ◽  
Dongbin Liu ◽  
Nasarul Wahab ◽  
...  

<p>The ZSM-5, g-Al<sub>2</sub>O<sub>3</sub>, SiO<sub>2</sub> and MgO supported Pd-catalysts were prepared for the phenol hydrogenation to cyclohexanone in liquid-phase. The natures of these catalysts were characterized by XRD, N<sub>2</sub> adsorption-desorption analysis, H<sub>2</sub>-TPR, CO<sub>2</sub>-TPD and NH<sub>3</sub>-TPD. The catalytic performance of the supported Pd-catalyst for phenol hydrogenation to cyclohexanone is closely related to nature of the support and the size of Pd nanoparticles. The Pd/MgO catalyst which possesses higher basicity shows higher cyclohexanone selectivity, but lower phenol conversion owing to the lower specific surface area. The Pd/SiO<sub>2</sub> catalyst prepared by precipitation gives higher cyclohexanone selectivity and phenol conversion, due to the moderate amount of Lewis acidic sites, and the smaller size and higher dispersion of Pd nanoparticles on the surface. Under the reaction temperature of 135 <sup>o</sup>C and H<sub>2</sub> pressure of 1 MPa, after reacting for 3.5 h, the phenol conversion of 71.62% and the cyclohexanone selectivity of 90.77% can be obtained over 0.5 wt% Pd/SiO<sub>2</sub> catalyst. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 7<sup>th</sup> March 2016; Revised: 13<sup>rd</sup> May 2016; Accepted: 7<sup>th</sup> June 2016</em></p><p><strong>How to Cite:</strong> Fan, L., Zhang, L., Shen, Y., Liu, D., Wahab, N., Hasan, M.M. (2016). Liquid-phase Hydrogenation of Phenol to Cyclohexanone over Supported Palladium Catalysts. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (3): 354-362 (doi: 10.9767/bcrec.11.3.575.354-362)</p><p><strong>Permalink/DOI</strong>: <a href="http://doi.org/10.9767/bcrec.11.3.575.354-362">http://doi.org/10.9767/bcrec.11.3.575.354-362</a></p>


Sign in / Sign up

Export Citation Format

Share Document