scholarly journals BUTENEDIOLS PRODUCTION FROM ERYTHRITOL ON Rh PROMOTED CATALYST

2020 ◽  
Vol 50 (2) ◽  
pp. 89-94
Author(s):  
Emanuel Martín Virgilio ◽  
Cristina Liliana Padró ◽  
Maria Eugenia Sad
Keyword(s):  
Bimetallic Catalyst ◽  
Good Activity ◽  
Reaction Conditions ◽  
Total Conversion ◽  
Reaction Orders ◽  
Temperature Programmed ◽  
Lower Temperature ◽  
Low Activity ◽  
Monometallic Catalyst ◽  
Lower Carbon

The C-O hydrogenolysis of Erythritol to Butanodiols was studied in aqueous solution at 473 K and 25 bar of H2 using Rh/ReOx/TiO2 and the monometallic Rh/TiO2 and ReOx/TiO2 catalysts. The solids were characterized by temperature programmed reduction (TPR), TEM and XPS. TPR and XPS showed that ReOx species are close to Rh particles leading to reduction at lower temperature than Re on monometallic catalyst. However, some segregated Rhenium species were suspected by TPR profile for the bimetallic catalyst and detected by TEM.  Re/TiO2 exhibited low activity forming only products from dehydration and epimerization. Although Rh/TiO2 showed high activity (total conversion at 14 h), was more selective to C-C cleavage leading to lower carbon products. Rh/ReOx/TiO2, showed instead, a good activity and selectivity towards C-O hydrogenolysis route yielding 37.5% of Butanodiols. Activation energy and reaction orders on ERY (0.58) and H2 (0.53) were estimated from experiences made at different reaction conditions

Bimetallic Co and Mn Supported on Hydroxyapatite Catalyst for Carbon Monoxide Oxidation at Lower Temperature

2021 ◽  
Author(s):  
Rahul More ◽  
Pavan More
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Co Oxidation ◽  
Bimetallic Catalyst ◽  
Active Species ◽  
Deposition Method ◽  
Oxidation Of Co ◽  
Oxidation Activity ◽  
Lower Temperature ◽  
Monometallic Catalyst

Abstract The series of bimetallic Co and Mn supported on hydroxyapatite catalyst were prepared by successive deposition method and examined for CO oxidation. The CO oxidation activity was compared with monometallic Mn/HAp and Co/HAp. The catalysts are characterized in detail and correlated to the oxidation activity. The XRD, XPS and TPR characterization showed the presence of more facile Co2+, Mn3+ and adsorbed oxygen due to the interaction between Mn and Co. The 0.4 mol Mn and 0.1 mol Mn deposited on HAp showed formation of maximum active species. The maximum CoO species was observed over bimetallic catalyst compared to the monometallic catalyst. These active lower the activation energy require for CO and oxygen. These species were responsible for the oxidation of CO at lower temperature compared to the remaining catalyst.

Selectivity changes of acetone transformation over ZSM-5 zeolites with different acido-basic properties

1989 ◽  
Vol 54 (8) ◽  
pp. 2054-2063 ◽  
Author(s):  
Jiří Čejka ◽  
Ludmila Kubelková ◽  
Pavel Jírů
Keyword(s):  
Main Product ◽  
High Conversion ◽  
Total Conversion ◽  
Basic Properties ◽  
Product Composition ◽  
Conversion Level ◽  
Integral Reactor ◽  
Low Activity ◽  
High Conversion Level

Acetone transformation catalyzed by HZSM-5 and NaZSM-5 zeolites and by zeolites modified with basic oxides was studied in an integral reactor at a temperature of 350 °C. Modification of acido-basic properties of ZSM-5 zeolites resulted both in the total conversion changes and in the essential changes in the product composition. Isobutene was found to be the main product over HZSM-5 zeolites exhibiting low activity, while aromatics prevailed when high conversion level was attained. Classical condensation of acetone yielding mesityloxide and phorones was observed over NaZSM-5 zeolites impregnated with CaO and ZnO.

scholarly journals Modeling, optimization and experimental studies of supported nano-bimetallic catalyst for simultaneous total conversion of toluene and cyclohexane in air using a hybrid intelligent algorithm

RSC Advances ◽  
2018 ◽  
Vol 8 (31) ◽  
pp. 17346-17356 ◽  
Author(s):  
Mohammad Zabihi ◽  
Nasser Babajani
Keyword(s):  
Activated Carbon ◽  
Bimetallic Catalysts ◽  
Bimetallic Catalyst ◽  
Experimental Studies ◽  
Deep Oxidation ◽  
Intelligent Algorithm ◽  
Almond Shell ◽  
Total Conversion ◽  
Hybrid Intelligent Algorithm

This study reveals the simultaneous deep oxidation of toluene and cyclohexane over optimal supported bimetallic catalysts over almond shell based activated carbon.

Facile Synthesis, Morphology Evolution and Tunable Luminescence of NaGdF4:Yb,Er Nanorods with Various Aspect Ratios

NANO ◽  
2018 ◽  
Vol 13 (08) ◽  
pp. 1850093 ◽  
Author(s):  
Shasha Gai ◽  
Jiqing Jiao ◽  
Wei Wei ◽  
Yao Li ◽  
Lihua Liu ◽  
...  
Keyword(s):  
Energy Level ◽  
Hydrothermal Method ◽  
Growth Mechanism ◽  
Morphology Evolution ◽  
Schematic Diagram ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
Facile Hydrothermal Method ◽  
Aspect Ratios ◽  
Lower Temperature

The well-defined NaGdF4:Yb,Er nanorods (NRs) with various aspect ratios were synthesized using a facile hydrothermal method. The morphology and crystal phase of NRs could be controlled by reaction conditions. NaGdF4:Yb,Er NRs with various aspect ratios could be synthesized and their upconversion (UC) luminescence was tuned. It is displayed that the NRs with aspect ratios about 5 exhibited the strongest UC luminescence among samples. The growth mechanism and morphology transition of NRs had been deduced by schematic diagram. And UC mechanism had been determined by energy level diagrams. Compared with previous reports, the work provided a facial method for UCNRs with various aspect ratios at lower temperature.

Nanostructured Co3O4 Oxide for Low Temperature Ethanol Oxidation

2014 ◽  
Vol 798-799 ◽  
pp. 205-210
Author(s):  
Jairo Alberto Gomez-Cuaspud ◽  
Martin Schmal
Keyword(s):  
Ethanol Oxidation ◽  
Physicochemical Characterization ◽  
Fluorescence Analysis ◽  
Product Distribution ◽  
X Ray Diffraction ◽  
Ethanol Oxidation Reaction ◽  
Reaction Conditions ◽  
X Ray ◽  
Temperature Programmed ◽  
Combustion Technique

We investigated the synthesis of nanosized Co3O4 oxide by the polymerization-combustion technique, with different concentrations (3, 12 and 25% w/w) in the ethanol oxidation reaction. Characterization was done by X-ray fluorescence analysis, X-ray diffraction, temperature programmed reduction, scanning and transmission electronic microscopy and CO and H2 chemisorption. Principal results from physicochemical characterization show that the concentration of the metal oxide influence the product distribution and selectivity under isothermal conditions at 420 °C showed the formation of intermediate etoxi-species and preferential dehydrogenation reaction on stream of material. Specific concentrations result in high conversions and H2 selectivity under present reaction conditions.

scholarly journals Supported Gold Nanoparticles as Catalysts in Peroxidative and Aerobic Oxidation of 1-Phenylethanol under Mild Conditions

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 151 ◽  
Author(s):  
Ekaterina Pakrieva ◽  
Ana P. C. Ribeiro ◽  
Ekaterina Kolobova ◽  
Luísa M. D. R. S. Martins ◽  
Sónia A. C. Carabineiro ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Density Functional ◽  
Aerobic Oxidation ◽  
Reaction Conditions ◽  
Tert Butyl Hydroperoxide ◽  
Temperature Programmed ◽  
Pretreatment Atmosphere ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

The efficiency of Au/TiO2 based catalysts in 1-phenylethanol oxidation was investigated. The role of support modifiers (La2O3 or CeO2), influence of gold loading (0.5% or 4%) and redox pretreatment atmosphere, catalyst recyclability, effect of oxidant: tert-butyl hydroperoxide (TBHP) or O2, as well as the optimization of experimental parameters of the reaction conditions in the oxidation of this alcohol were studied and compared with previous studies on 1-octanol oxidation. Samples were characterized by temperature-programmed oxygen desorption (O2-TPD) method. X-ray photoelectron spectroscopy (XPS) measurements were carried out for used catalysts to find out the reason for deactivation in 1-phenylethanol oxidation. The best catalytic characteristics were shown by catalysts modified with La2O3, regardless of the alcohol and the type of oxidant. When O2 was used, the catalysts with 0.5% Au, after oxidative pretreatment, showed the highest activity in both reactions. The most active catalysts in 1-phenylethanol oxidation with TBHP were those with 4% Au and the H2 treatment, while under the same reaction conditions, 0.5% Au and O2 treatment were beneficial in 1-octanol oxidation. Despite the different chemical nature of the substrates, it seems likely that Au+(Auδ+) act as the active sites in both oxidative reactions. Density functional theory (DFT) simulations confirmed that the gold cationic sites play an essential role in 1-phenylethanol adsorption.

A temperature-programmed reaction/single-photon ionization time-of-flight mass spectrometry system for rapid investigation of gas–solid heterogeneous catalytic reactions under realistic reaction conditions

2015 ◽  
Vol 5 (11) ◽  
pp. 4959-4963 ◽  
Author(s):  
Songbo He ◽  
Huapeng Cui ◽  
Yulong Lai ◽  
Chenglin Sun ◽  
Sha Luo ◽  
...  
Keyword(s):  
Single Photon ◽  
Catalytic Reactions ◽  
Reaction Conditions ◽  
Ionization Time ◽  
Heterogeneous Catalytic ◽  
Flight Mass Spectrometry ◽  
Mass Spectrometry System ◽  
Photon Ionization ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction

A new TPRn/SPI-TOF-MS system for rapid investigation of realistic gas–solid heterogeneous catalytic reactions.

Friedel-Crafts Alkylation of o-xylene over V2O5 / ZrO2 Catalysts

2012 ◽  
Vol 11 (2) ◽  
pp. 1-16
Author(s):  
Sreejarani K Pillai ◽  
O Gheevarghese ◽  
I V Tleane
Keyword(s):  
Lewis Acidity ◽  
Bet Surface Area ◽  
High Yield ◽  
Impregnation Method ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Cumene Cracking ◽  
Wet Impregnation ◽  
Nmr Techniques ◽  
Temperature Programmed

The present study has undertaken the Friedel-Crafts benzylation of aromatics over the V2O5/ZrO2 catalysts systems. Catalysts with different V2O5 content (0-15wt %) was prepared by wet impregnation method and characterized by XRD, BET surface area, FTIR and 5’V NMR techniques. The surface acidic properties were determined by temperature programmed desorption of NH3, cumene cracking and perylene adsorption. Under the optimized reaction conditions, these catalysts are found to be very effective and considerably more selective than the conventional homogeneous Lewis acid catalysts. The investigation of vanadia systems-catalyzed benzylation of o-xylene with benzyl chloride revealed that the catalytic activity and product selectivity are sensitive to the precise reaction parameters and can be related to the Lewis acidity of the systems. The reaction is found to be very clean and produces the desired monoalkylated product with high yield.

scholarly journals Influence of Intercalation-Exfoliation-Reduction Technique towards the Physico-Chemical of VPO Catalysts

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Y. C. Wong ◽  
Y. H. Taufiq-Yap
Keyword(s):  
Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vpo Catalysts ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Vpo Catalyst ◽  
Temperature Programmed ◽  
Lower Temperature ◽  
Synthesized Materials

Four VPO catalysts were synthesized through intercalation and exfoliation in various alcohols and subsequent reduction of the exfoliated VOPO4sheets with various alcohols to produce VOHPO4⋅0.5H2O. The resulting VOHPO4⋅0.5H2O that undergoes the intercalation-exfoliation-reduction (IER) process will be further activated into VPO catalysts, and addition of 1 mole % Bi(NO3)3⋅5H2O in the first stage of this experiment has also being investigated. The synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and temperature-programmed reduction (TPR) in H2. Catalytic evaluation of the IER-treated and Bi-doped VPO catalysts was also studied on microreactor. The VPO catalyst produced through IER using 2-butanol and ethanol with addition of Bi, IERC(2Bu-Et)RBi1, gave the highest MA selectivity due to reactive O2−species released from the additional crystalline V5+phase formed by doping 1% bismuth as promoter (O2−-V5+pair) at relative lower temperature. Nevertheless, the VPO catalyst produced through IER using isobutanol, IERC(isoBu), gave the highest activity due to high amount of reactive O−species released from V4+phase (O−-V4+pair) whereby the IERC(isoBu) catalyst synthesized consists of high percentage of V4+(93 %).

Sign in / Sign up

Export Citation Format

Share Document