scholarly journals Co Loading Adjustment for the Effective Obtention of a Sedative Drug Precursor through Efficient Continuous-Flow Chemoselective Hydrogenation of 2-Methyl-2-pentenal

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Antonio Jesús Fernández-Ropero ◽  
Bartosz Zawadzki ◽  
Krzysztof Matus ◽  
Wojciech Patkowski ◽  
Mirosław Krawczyk ◽  
...  
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Continuous Flow ◽  
Hydrogen Adsorption ◽  
Bet Surface Area ◽  
Sedative Drug ◽  
X Ray ◽  
Chemoselective Hydrogenation ◽  
Temperature Programmed

This work presents the effect of Co loading on the performance of CNR115 carbon-supported catalysts in the continuous-flow chemoselective hydrogenation of 2-methyl-2-pentenal for the obtention of 2-methylpentanal, an intermediate in the synthesis of the sedative drug meprobamate. The Co loading catalysts (2, 6, 10, and 14 wt.%) were characterized by Brunauer–Emmett–Teller (BET) surface area analysis, transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), temperature-programmed desorption of hydrogen (H2-TPD) analysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy for selected samples, and have been studied as hydrogenation catalysts at different pressure and temperature ranges. The results reveal that a certain amount of Co is necessary to achieve significant conversion values. However, excessive loading affects the morphological parameters, such as the surface area available for hydrogen adsorption and the particle size, preventing an increase in conversion, despite the increased presence of Co. Moreover, the larger particle size, caused by increasing the loading, alters the chemoselectivity, favouring the formation of 2-methyl-2-pentenol and, thus, decreasing the selectivity towards the desired product. The 6 wt.% Co-loaded material demonstrates the best catalytic performance, which is related to the formation of NPs with optimum size. Almost 100% selectivity towards 2-methylpentanal was obtained for the catalysts with lower Co loading (2 and 6 wt.%).

scholarly journals Oxidized Palladium Supported on Ceria Nanorods for Catalytic Aerobic Oxidation of Benzyl Alcohol to Benzaldehyde in Protic Solvents

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 847 ◽  
Author(s):  
Seyed Moeini ◽  
Chiara Battocchio ◽  
Stefano Casciardi ◽  
Igor Luisetto ◽  
Paolo Lupattelli ◽  
...  
Keyword(s):  
Benzyl Alcohol ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Aerobic Oxidation ◽  
Bet Surface Area ◽  
Impregnation Method ◽  
X Ray ◽  
Protic Solvents ◽  
Oxidation Of Benzyl Alcohol ◽  
Temperature Programmed

In the present study, the catalytic activity of palladium oxide (PdOx) supported on ceria nanorods (CeO2-NR) for aerobic selective oxidation of benzyl alcohol (BnOH) to benzaldehyde (PhCHO) was evaluated. The CeO2-NR was synthesized hydrothermally and the Pd(NO3)2 was deposited by a wet impregnation method, followed by calcination to acquire PdOx/CeO2-NR. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), transmission electron microscopy (TEM), Brunauer–Emmet–Teller (BET) surface area analysis, and X-ray photoelectron spectroscopy (XPS). In addition, the TPR-reduced PdOx/CeO2-NR (PdOx/CeO2-NR-Red) was studied by XRD, BET, and XPS. Characterizations showed the formation of CeO2-NR with (111) exposed plane and relatively high BET surface area. PdOx (x > 1) was detected to be the major oxide species on the PdOx/CeO2-NR. The activities of the catalysts in BnOH oxidation were evaluated using air, as an environmentally friendly oxidant, and various solvents. Effects of temperature, solvent nature and palladium oxidation state were investigated. The PdOx/CeO2-NR showed remarkable activity when protic solvents were utilized. The best result was achieved using PdOx/CeO2-NR and boiling ethanol as solvent, leading to 93% BnOH conversion and 96% selectivity toward PhCHO. A mechanistic hypothesis for BnOH oxidation with PdOx/CeO2-NR in ethanol is presented.

scholarly journals Kinetics of Highly Active TiO2 Microspheres Formation in a Presence of Ethylammonium Nitrate Ionic Liquid

2018 ◽  
Author(s):  
Anna Gołąbiewska ◽  
Micaela Checa-Suárez ◽  
Marta Paszkiewicz-Gawron ◽  
Wojciech Lisowski ◽  
Edyta Raczuk ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Phenol Degradation ◽  
Bet Surface Area ◽  
Synthesis Time ◽  
X Ray ◽  
Highly Active

Spherical microparticles of TiO2 were synthesized by the ionic liquid-assisted solvothermal method at different reaction time (3, 6, 12 and 24h). The properties of the prepared photocatalysts were investigated by means of UV-vis diffuse-reflectance spectroscopy (DRS), BET surface area measurements, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicated that the efficiency of phenol degradation was related with a time of the solvothermal synthesis as determined for TiO2_EAN(1:1)_24h sample. Microparticles of TiO2_EAN(1:1)_3h formed during the only 3h of synthesis time revealed really high photoactivity under visible irradiation – 75%. This value increased to 80% and 82% after 12h and 24h, respectively. The photoactivity increase was accompanied by the increase of the specific surface area thus pores size, as well as ability to absorb UV-vis irradiation. The high efficiency of phenol degradation of IL-TiO2 photocatalysts was ascribed to the interaction between the surface of TiO2 and ionic liquid components (carbon and nitrogen).

Novel Organometallic Fullerene Complexes for Vehicular Hydrogen Storage

2007 ◽  
Vol 1041 ◽  
Author(s):  
Erin Whitney ◽  
Anne C. Dillon ◽  
Calvin Curtis ◽  
Chaiwat Engtrakul ◽  
Kevin O'Neill ◽  
...  
Keyword(s):  
Surface Area ◽  
Hydrogen Adsorption ◽  
Binding Energies ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
Adsorption Sites ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Temperature Programmed

AbstractExperimental wet chemical approaches have been demonstrated in the synthesis of a new chainlike (C60-Fe-C60-Fe)n complex. This structure has been proposed based on 13C solid-state nuclear magnetic resonance, electron paramagnetic resonance, high-resolution transmission electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. Furthermore, this structure has been shown to have unique binding sites for dihydrogen molecules with the technique of temperature-programmed desorption. The new adsorption sites have binding energies that are stronger than that observed for hydrogen physisorbed on planar graphite, but significantly weaker than a chemical C-H bond. Volumetric measurements at 77 K and 2 bar show a hydrogen adsorption capacity of 0.5 wt%. Interestingly, the BET surface area is ∼31 m2/g after degassing, which is approximately an order of magnitude less than expected given the measured experimental hydrogen capacity. Nitrogen and hydrogen isotherms performed at 75 K also show a marked selectivity for hydrogen over nitrogen for this complex, indicating hidden surface area for hydrogen adsorption.

scholarly journals Propane and Naphthalene Oxidation over Gold-Promoted Cobalt Catalysts Supported on Zirconia

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 387
Author(s):  
María Silvia Leguizamón Aparicio ◽  
María Lucia Ruiz ◽  
Marco Antonio Ocsachoque ◽  
Marta Isabel Ponzi ◽  
Enrique Rodríguez-Castellón ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Cobalt Catalysts ◽  
Bet Surface Area ◽  
Promoting Effect ◽  
Propane Combustion ◽  
X Ray ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Supported Gold

Zirconia-supported gold-promoted cobalt catalysts were synthesized and tested for the complete oxidation of propane and naphthalene. The catalysts were characterized by BET surface area, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). In both propane and naphthalene combustion reactions, the results obtained indicate that catalysts formulated with Co3O4 are more active than those containing only Au. Catalysts prepared using the deposit/precipitation (DP) method have better activity than those in which the traditional technique is used. Gold addition using the DP methods generates a promoting effect on the activity of cobalt-containing catalysts. The AuDpCoZt catalyst was found to be the most active for both propane and naphthalene combustion. The catalytic behavior of this sample is associated with a synergic effect between gold, cobalt, and the support, which is also evidenced by an increase in the reducibility of this catalytic system. The effect of the presence of NO in the feed was also analyzed for propane combustion.

Chamosite, a naturally occurring clay as a versatile catalyst for various organic transformations

Clay Minerals ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 281-299 ◽  
Author(s):  
R. Arundhathi ◽  
B. Sreedhar ◽  
G. Parthasarathy
Keyword(s):  
Photoelectron Spectroscopy ◽  
Tamil Nadu ◽  
Layer Structure ◽  
Bet Surface Area ◽  
Silicate Layer ◽  
Reusable Catalyst ◽  
Organic Transformations ◽  
X Ray ◽  
Naturally Occurring ◽  
Temperature Programmed

AbstractThe chlorite-group mineral chamosite occurs in nanocrystalline form (~200 nm grain size) as a naturally occurring clay in the Quaternary marine sedimentary deposits near Kudiamozhi, Tuticorin District, Tamil Nadu, India; samples were used in this study as a reusable catalyst. The clay has the usual alternating tetrahedral-octahedral-tetrahedral silicate/aluminate/silicate layer structural arrangement (sometimes called the 2:1 silicate or talc layer structure). The interlayer and the t-o-t layer are bound together by both electrostatic and hydrogen-bonding forces. This natural clay catalyst has been well characterized by various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD), temperature programmed desorption (TPD), thermal analysis and BET surface area measurements (Sreedhar et al., 2009); it has been utilized for various organic transformations such as acylation of alcohols and amines, cyclization of arylaldehydes with O-phenylenediamines and C-O bond formation reactions.

scholarly journals The Effect of Using H4P2O7 as Phosphorus Source for Synthesizing Vanadyl Pyrophosphate Catalysts

2017 ◽  
Vol 6 (3) ◽  
pp. 207
Author(s):  
Y.H. Taufiq-Yap ◽  
A. Raslan ◽  
R. Irmawati
Keyword(s):  
Surface Area ◽  
Area Measurement ◽  
Bet Surface Area ◽  
Vanadyl Pyrophosphate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Area Measurement ◽  
Phosphorus Source ◽  
Temperature Programmed ◽  
Two Peaks

<p>Vanadyl pyrophosphate (VO)<sub>2</sub>P<sub>2</sub>O<sub>7</sub> catalysts synthesized via VOPO<sub>4</sub>·2H<sub>2</sub>O were investigated by using BET surface area measurement, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Temperature-Programmed Techniques (TPD and TPRS). H<sub>3</sub>PO<sub>4</sub> and H<sub>4</sub>P<sub>2</sub>O<sub>7</sub> were used as the phosphorus source. Only pyrophosphate phase was observed for both final catalysts after 75 hours of calcination in a reaction flow of <em>n</em>-butane/air mixture (0.75% <em>n</em>-butane/air). However, catalyst derived from H<sub>4</sub>P<sub>2</sub>O<sub>7</sub> based preparation (denoted VPD<sub>pyro</sub>) exhibit better crystallinity and slightly higher BET surface area compared to the H<sub>3</sub>PO<sub>4</sub> based preparation (denoted VPD<sub>ortho</sub>). The nature of the oxidants for both catalysts was investigated by O<sub>2</sub>-TPD. For VPD<sub>pyro</sub>, TPD showed an oxygen peak maximum at 986 K and a shoulder at 1003 K, whereas for VPD<sub>ortho</sub>, the oxygen was desorbed as two peaks maxima at 966 and 994 K. The total amount of oxygen desorbed thermally from VPD<sub>pyro</sub> (3.60×10<sup>20</sup> atom×g<sup>-1</sup>) is higher than that obtained for VPD<sub>ortho</sub> (3.07×10<sup>20</sup> atom×g<sup>-1</sup>). VPD<sub>pyro</sub> displayed a slightly improved activity and selectivity for <em>n</em>-butane oxidation. A proper amount of V<sup>5+</sup> species may have an effect on the enhancement of the catalytic activity.</p>

scholarly journals Modification of Carbon Black with Hydrogen Peroxide for High Performance Anode Catalyst of Direct Methanol Fuel Cells

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3902
Author(s):  
Yu-Wen Chen ◽  
Han-Gen Chen ◽  
Man-Yin Lo ◽  
Yan-Chih Chen
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Surface Area ◽  
Functional Groups ◽  
Methanol Oxidation ◽  
Photoelectron Spectroscopy ◽  
Direct Methanol Fuel Cells ◽  
Reducing Agent ◽  
Precipitation Method ◽  
X Ray

In this study, high-surface-area carbon black is used to support PtRu. In order to increase the functional groups on the surface of carbon black and to have a more homogenous dispersed PtRu metal, the surface of carbon black is functionalized by H2O2. PtRu/carbon black is synthesized by the deposition–precipitation method. NaH2PO2 is used as the reducing agent in preparation. These catalysts are characterized by N2 sorption, temperature-programmed desorption, X-ray diffraction, transmission electron microscope, and X-ray photoelectron spectroscopy. The methanol oxidation ability of the catalyst is tested by cyclic voltammetry measurement. Using H2O2 to modify carbon black can increase the amount of functional groups on the surface, thereby increasing the metal dispersion and decreasing metal particle size. NaH2PO2 as a reducing agent can suppress the growth of metal particles. The best modified carbon black catalyst is the one modified with 30% H2O2. The methanol oxidation activity of the catalyst is mainly related to the particle size of PtRu metal, instead of the surface area and conductivity of carbon black. The PtRu catalyst supported by this modified carbon black has very high activity, with an activity reaching 309.5 A/g.

scholarly journals Characteristics of High Surface Area Molybdenum Nitride and Its Activity for the Catalytic Decomposition of Ammonia

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 192
Author(s):  
Seo-Hyeon Baek ◽  
Kyunghee Yun ◽  
Dong-Chang Kang ◽  
Hyejin An ◽  
Min Bum Park ◽  
...  
Keyword(s):  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Decomposition ◽  
Molybdenum Nitride ◽  
X Ray ◽  
Temperature Programmed Oxidation ◽  
Oxidation Reduction ◽  
Temperature Programmed

High surface area (>170 m2 g−1) molybdenum nitride was prepared by the temperature-programmed nitridation of α-MoO3 with pure ammonia. The process was optimized by adjusting the experimental variables: the reaction temperature, heating rate, and molar flow rate of ammonia. The physicochemical properties of the as-formed molybdenum nitride were characterized by X-ray diffraction, N2 sorption, transmission electron microscopy, temperature-programmed oxidation/reduction, and X-ray photoelectron spectroscopy. Of the experimental variables, the nitridation temperature was found to be the most critical parameter determining the surface area of the molybdenum nitride. When the prepared molybdenum nitride was exposed to air, the specific surface area rapidly decreased because of the partial oxidation of molybdenum nitride to molybdenum oxynitride. However, the surface area recovered to 90% the initial value after H2 treatment. The catalyst with the highest degree of nitridation showed the best catalytic activity, superior to that of unmodified α-MoO3, for the decomposition of ammonia because of its high surface area.

scholarly journals Synthesis and Catalytic Performance of Ni/SiO2for Hydrogenation of 2-Methylfuran to 2-Methyltetrahydrofuran

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Fu Ding ◽  
Yajing Zhang ◽  
Guijin Yuan ◽  
Kangjun Wang ◽  
Ileana Dragutan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ni Content ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Ni Species

A series of Ni/SiO2catalysts with different Ni content were prepared by sol-gel method for application in the synthesis of 2-methyltetrahydrofuran (2-MTHF) by hydrogenation of 2-methylfuran (2-MF). The catalyst structure was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR). It is found that structures and catalytic performance of the catalysts were highly affected by the Ni content. The catalyst with a 25% Ni content had an appropriate size of the Ni species and larger BET surface area and produced a higher 2-MF conversion with enhanced selectivity in 2-MTHF.

Improvement of physico-chemical properties by addition of H2O2: An extensive case study on the RE-doped ceria system (RE = Gd, Sm)

2009 ◽  
Vol 24 (9) ◽  
pp. 2845-2854 ◽  
Author(s):  
Balaji P. Mandal ◽  
Vinita Grover ◽  
Mrinal R. Pai ◽  
Avesh K. Tyagi
Keyword(s):  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Powder Properties ◽  
Temperature Programmed

Effect of H2O2 on synthesis and powder properties such as surface area and agglomerate size of nanocrystalline Ce0.8M0.2O1.90 (M: Sm, Gd) was explored by treating cerium nitrate and rare-earth nitrate with NaOH in the presence/absence of H2O2. The resultant products were characterized by x-ray diffraction, Raman spectroscopy, thermo-gravimetry–differential thermal analysis, dynamic light scattering, surface area analysis, high-resolution transmission electron microscopy, and x-ray photoelectron spectroscopy. The presence of H2O2 was found to have a profound effect on powder properties such as surface area and particle size of these doped ceria samples and results in smaller crystallite size, softer agglomerates, and larger surface area. A mechanism is proposed to explain the observed better powder properties of the samples. It was also shown that the samples prepared in the presence of H2O2 can lower the conversion temperature of CO to CO2, proving these to be better catalysts. Interestingly, temperature-programmed reduction studies on Sm3+-doped samples showed that the doping in conjunction with the use of H2O2 leads to enhanced reduction properties of the samples over multiple cycles.

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