Gas phase hydrogenation of o-xylene on Ru supported catalysts

1993 ◽  
Vol 49 (2) ◽  
pp. 353-360 ◽  
Author(s):  
M. Viniegra ◽  
N. Martín ◽  
A. López-Gaona ◽  
G. Córdoba
Keyword(s):  
Gas Phase ◽  
Supported Catalysts

scholarly journals Towards High Efficacy of Pd-Au/C Catalyst for Tetrachloromethane Hydrodechlorination

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 338-359
Author(s):  
Magdalena Bonarowska ◽  
Zbigniew Kaszkur ◽  
Krzysztof Matus ◽  
Alicja Drelinkiewicz ◽  
Tomasz Szumełda ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Gas Phase ◽  
Thermal Activation ◽  
Supported Catalysts ◽  
Carbon Support ◽  
Thermal Reduction ◽  
Microwave Oven ◽  
Optimal Conditions ◽  
Catalyst Activation ◽  
Critical Part

We present an efficient strategy for synthesising the PdAu catalysts with a homogeneous PdAu alloy phase for environmentally important hydrodechlorination of tetrachloromethane in the gas phase. The synthesis of carbon-supported catalysts involved two major steps: (i) incorporation of palladium and gold nanoparticles into carbon support and (ii) activation of the catalysts. The critical part of this work was to find the optimal conditions for both steps. Thus, the incorporation of the nanoparticles was carried out in two ways, by impregnation and direct redox reaction method using acetone solutions of metal precursor salts. The activation was performed either by a conventional thermal reduction in hydrogen or flash irradiation in a microwave oven. The homogeneity and structure of the PdAu alloy were found to depend on the catalyst activation method critically. In all cases, we observed better homogeneity for catalysts that were subject to microwave irradiation. Moreover, the flash microwave irradiation of prepared catalysts provided catalysts of better stability and selectivity towards the desired products (hydrocarbons) in the hydrodechlorination of tetrachloromethane as compared to the catalyst obtained by conventional thermal activation in hydrogen.

Laser electrodispersion as a new chlorine-free method for the production of highly effective metal-containing supported catalysts

2012 ◽  
Vol 84 (3) ◽  
pp. 495-508 ◽  
Author(s):  
Ekaterina S. Lokteva ◽  
Anton A. Peristyy ◽  
Natalia E. Kavalerskaya ◽  
Elena V. Golubina ◽  
Lada V. Yashina ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Stability ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Promising Technique ◽  
Wet Impregnation ◽  
Oxide Supports ◽  
Highly Active ◽  
Specific Catalytic Activity ◽  
Free Metal

Laser electrodispersion (LED) of metals is a promising technique for the preparation of heterogeneous catalysts as an alternative to wet impregnation of supports with the corresponding salt solutions. The LED technique can be used to deposit highly active chloride- and nitrate-free metal nanoparticles onto carbon or oxide supports. We report preparation and properties of new Ni-, Pd-, and Au-containing alumina-supported catalysts with low metal loadings (10–3–10–4 % mass) and their comparison with the previously studied carbon (Sibunit) supported systems. The catalysts demonstrate high stability and extremely high specific catalytic activity (by 2–3 orders of magnitude higher than for traditional catalysts) in the gas-phase hydrodechlorination (HDC) of chlorobenzene (CB).

scholarly journals Gas phase synthesis of isopropyl chloride from isopropanol and HCl over alumina and flexible 3-D carbon foam supported catalysts

2017 ◽  
Vol 542 ◽  
pp. 212-225
Author(s):  
Natalia Bukhanko ◽  
Christopher Schwarz ◽  
Ajaikumar Samikannu ◽  
Tung Ngoc Pham ◽  
William Siljebo ◽  
...  
Keyword(s):  
Gas Phase ◽  
Supported Catalysts ◽  
Carbon Foam ◽  
Phase Synthesis ◽  
Gas Phase Synthesis

Selective Hydrogenation of Crotonaldehyde Over Cobalt Based Self-Supported Catalysts

1994 ◽  
Vol 368 ◽  
Author(s):  
A. N. Patil ◽  
M. A. Bañares ◽  
X. Lei ◽  
T. P. Fehlner ◽  
E. E. Wolf
Keyword(s):  
Gas Phase ◽  
Supported Catalysts ◽  
Catalyst Activity ◽  
Maximum Yield ◽  
Metal Core ◽  
Molecular Precursors ◽  
Crotyl Alcohol ◽  
Carboxylate Groups ◽  
Heterogenous Catalyst ◽  
Metal Layers

ABSTRACTComplex cobalt-carbonyl ligand based clusters of clusters are used as molecular precursors for self-supported model catalysts. These precursors consist of two metal layers: an outer of the complex Co-carbonyl ligands, and a core of metal (e.g. Co or Zn) carboxylate groups. Partial thermolysis at low temperature (LT) of these materials under hydrogen results in almost completely decarbonylated material with a mainly unchanged carboxylate metal core. Complete pyrolysis at higher temperatures (HT) in hydrogen leads to mixed metal environment. These materials were used as a heterogenous catalyst in the gas phase hydrogenation of crotonaldehyde. The maximum yield of 27 % of desired product crotyl alcohol was observed when HT-CoCo was used as the catalyst at 423 K. The catalyst activity and the crotyl alcohol selectivity remained unchanged over 2 days of operation. The bimetallic ZnCo catalysts showed lower selectivity to crotyl alcohol than the CoCo catalysts.

Selective gas phase hydrogenation of maleic anhydride over Ni-supported catalysts: Effect of support on the catalytic performance

2012 ◽  
Vol 449 ◽  
pp. 81-87 ◽  
Author(s):  
Silvina A. Regenhardt ◽  
Camilo I. Meyer ◽  
Teresita F. Garetto ◽  
Alberto J. Marchi
Keyword(s):  
Maleic Anhydride ◽  
Gas Phase ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Effect Of Support ◽  
Ni Supported Catalysts

Hollownano-MgF2 supported catalysts: Highly active and stable in gas-phase dehydrofluorination of 1,1,1,3,3-pentafluoropropane

2018 ◽  
Vol 238 ◽  
pp. 599-608 ◽  
Author(s):  
Zhaohua Jia ◽  
Wei Mao ◽  
Yanbo Bai ◽  
Bo Wang ◽  
Hui Ma ◽  
...  
Keyword(s):  
Gas Phase ◽  
Supported Catalysts ◽  
Highly Active

Supported Catalysts in Stirred Bed Gas Phase Reactors

1993 ◽  
pp. 31-45 ◽  
Author(s):  
K. D. Hungenberg ◽  
M. Kersting
Keyword(s):  
Gas Phase ◽  
Supported Catalysts

Three-Phase Model of a Fluidized-Bed Catalytic Reactor for Polyethylene Synthesis

2016 ◽  
Vol 14 (1) ◽  
pp. 93-103 ◽  
Author(s):  
R. A. Bortolozzi ◽  
M. G. Chiovetta
Keyword(s):  
Gas Phase ◽  
Fluidized Bed ◽  
Solid Particle ◽  
Active Sites ◽  
Supported Catalysts ◽  
Plug Flow ◽  
Solid Particles ◽  
Particle Phase ◽  
Three Phase ◽  
Bubbling Fluidized Bed

AbstractA mathematical model of a bubbling fluidized-bed reactor for the production of polyolefins is presented. The model is employed to simulate a typical, commercial-scale reactor where the synthesis of polyethylene using supported catalysts is carried out. Results are used to follow the evolution of temperature within the reactor bed to avoid conditions producing polymer degradation. The fluidized bed is modeled as a heterogeneous system with a bubble gas phase and a solid-particle emulsion. The catalyst active sites are considered located within a growing, solid, ever changing particle composed of the support, the catalyst and the polymer being produced. The model sees the reactor as a three phase complex: (a) the bubble phase, transporting most of the gas entering the reactor; (b) the solid-particle phase, where polymerization takes place; and (c) the interstitial-gas phase among solid particles. Both gaseous phases move continuously upward, with different velocities, and are modeled as plug flows. For the solid-particle phase, modeling alternatives are explored, ranging from a descending plug-flow limiting case to the opposite extreme of a perfectly mixed tank related to the particle drag-effect the rising bubble produces in the bed. In the scouting process between these limits instabilities are predicted by the model. The most realistic representation of the bed is that of the two gas phases moving upward in two plug-flow patterns and the solids moving with ascending and descending trajectories due to back-mixing.

Sign in / Sign up

Export Citation Format

Share Document