scholarly journals Modifications in the Composition of CuO/ZnO/Al2O3 Catalyst for the Synthesis of Methanol by CO2 Hydrogenation

2021 ◽  
Author(s):  
Bianca Trifan ◽  
Javier Lasobras ◽  
Jaime Soler ◽  
Javier Herguido ◽  
Miguel Menéndez
Keyword(s):  
High Pressure ◽  
Renewable Energy ◽  
Heterogeneous Catalysts ◽  
High Selectivity ◽  
Efficient Catalyst ◽  
Synthesis Time ◽  
Mild Conditions ◽  
Temperature And Pressure ◽  
Synthesis Of Methanol ◽  
Co Precipitation

Renewable methanol, obtained from CO2 and hydrogen provided from renewable energy, has been proposed as a way to close the CO2 loop. In industry, methanol synthesis using the catalyst CuO/ZnO/Al2O3 occurs at a high pressure. We intend to make certain modification on the traditional catalyst in order to work at lower pressure, maintaining high selectivity. Therefore, three heterogeneous catalysts have been synthesized by co-precipitation in order to improve the activity and the selectivity to methanol under mild conditions of temperature and pressure. Certain modifications on the traditional catalyst Cu/Zn/Al2O3 were employed such as the modification of the synthesis time and the addition of Pd as a dopant agent. The most efficient catalyst among those tested was a palladium-doped catalyst, 5% Pd/Cu/Zn/Al2O3. This had a selectivity of 64% at 210C and 5 bar.

scholarly journals Modifications in the Composition of CuO/ZnO/Al2O3 Catalyst for the Synthesis of Methanol by CO2 Hydrogenation

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 774
Author(s):  
Bianca Trifan ◽  
Javier Lasobras ◽  
Jaime Soler ◽  
Javier Herguido ◽  
Miguel Menéndez
Keyword(s):  
High Pressure ◽  
Heterogeneous Catalysts ◽  
High Selectivity ◽  
Co2 Hydrogenation ◽  
Efficient Catalyst ◽  
Synthesis Time ◽  
Mild Conditions ◽  
Temperature And Pressure ◽  
Synthesis Of Methanol ◽  
Al2o3 Catalyst

Renewable methanol, obtained from CO2 and hydrogen provided from renewable energy, was proposed to close the CO2 loop. In industry, methanol synthesis using the catalyst CuO/ZnO/Al2O3 occurs at a high pressure. We intend to make certain modification on the traditional catalyst to work at lower pressure, maintaining high selectivity. Therefore, three heterogeneous catalysts were synthesized by coprecipitation to improve the activity and the selectivity to methanol under mild conditions of temperature and pressure. Certain modifications on the traditional catalyst Cu/Zn/Al2O3 were employed such as the modification of the synthesis time and the addition of Pd as a dopant agent. The most efficient catalyst among those tested was a palladium-doped catalyst, 5% Pd/Cu/Zn/Al2O3. This had a selectivity of 64% at 210 °C and 5 bar.

Selective direct hydroxylation of benzene to phenol with hydrogen peroxide by iron and vanadyl based homogeneous and heterogeneous catalysts

2016 ◽  
Vol 6 (22) ◽  
pp. 8166-8176 ◽  
Author(s):  
Liliana Carneiro ◽  
Ana Rosa Silva
Keyword(s):  
Hydrogen Peroxide ◽  
Heterogeneous Catalysts ◽  
High Selectivity ◽  
Mild Conditions ◽  
Hydroxylation Of Benzene ◽  
Very High ◽  
Direct Hydroxylation

With our homogeneous and heterogeneous catalysts, very high selectivity to phenol was achieved, with yields comparable to or higher than the ones reported in the literature, under mild conditions.

Microwave-Assisted Decarbonylation of Biomass-Derived Aldehydes Using Pd-Doped Hydrotalcites

2019 ◽  
Author(s):  
Nan An ◽  
Diana Ainembabazi ◽  
Kavya Samudrala ◽  
Christopher Reid ◽  
Kare Wilson ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Reaction Times ◽  
Inverse Correlation ◽  
Mulliken Charge ◽  
Metal Leaching ◽  
Carbonyl Carbon ◽  
Mild Conditions ◽  
Microwave Assisted ◽  
Biomass Processing ◽  
Alcohol Dehydrogenation

<p>Here we report the synthesis, characterization and activity of tunable Pd-doped hydrotalcites (Pd-HTs) for the decarbonylation of furfural, hydroxymethylfurfural (HMF), aromatic and aliphatic aldehydes under microwave conditions. The decarbonylation activity reported is a notable improvement over prior heterogeneous catalysts for this process. Furfural decarbonylation is optimized in a benign solvent compatible with biomass processing - ethanol, under relatively mild conditions and short reaction times. HMF selectively affords excellent yields of furfuryl alcohol with no humin formation, but longer reaction can also afford furan via tandem alcohol dehydrogenation and decarbonylation. Yields of substituted benzaldehydes are related to calculated Mulliken charge of the carbonyl carbon. The activity and selectivity differences can be traced to loading-dependent differences in Pd speciation on the catalysts. Poisoning studies show inverse correlation between Pd loading and metal leaching: Pd-HTs with lowest Pd loading, which consist of highly dispersed and oxidized Pd species, operate heterogeneously with negligible metal leaching. Recycling experiments are consistent with this trend, offering potential for further optimization to improve robustness.</p>

Chiral Mn(III) Salen Complex Immobilized on CuFe2O4@SiO2-NH2 NPs: A Cheap and Efficient Catalyst for N-arylation of Aryl Halides and Phenylboronic Acid Under Mild Conditions

2020 ◽  
Vol 17 (11) ◽  
pp. 857-863
Author(s):  
Mohammad Ali Nasseri ◽  
Seyyedeh Ameneh Alavi ◽  
Milad Kazemnejadi ◽  
Ali Allahresani
Keyword(s):  
Phenylboronic Acid ◽  
Significant Loss ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Efficient Catalyst ◽  
Aryl Chlorides ◽  
Mild Conditions ◽  
Cross Coupling Reactions ◽  
Salen Complex ◽  
Ft Ir

A convenient and efficient chiral CuFe2O4@SiO2-Mn(III) Ch.salen nanocatalyst has been developed for the C-N cross-coupling reactions of aryl halides/ phenylboronic acid with N-heterocyclic compounds in water and/or DMSO under mild conditions. The catalyst could be applied for the N-arylation of a variety of nitrogen-containing heterocycles with aryl chlorides, bromides, iodides and phenylboronic acid under mild conditions. Moderate to good yields were achieved for all substrates. The structure of catalyst was characterized using various techniques including FT-IR, FE-SEM, EDX, XRD, TEM and TGA. The catalyst can be simply recovered and reused for several times without significant loss of activity.

4-Hydroxy Pyridinium Triflate@SiO2 Nanoparticles as a Novel Efficient Catalyst for Fries Rearrangement of Aryl Esters with High Selectivity

2020 ◽  
Vol 17 (8) ◽  
pp. 654-660
Author(s):  
Shermineh Sadat Ghalehbandi ◽  
Dadkhoda Ghazanfari ◽  
Sayed Ali Ahmadi ◽  
Enayatollah Sheikhhosseini
Keyword(s):  
High Selectivity ◽  
Sio2 Nanoparticles ◽  
High Yield ◽  
Synthetic Method ◽  
Functionalized Silica ◽  
Efficient Catalyst ◽  
Fries Rearrangement ◽  
Free Condition ◽  
Solvent Free Condition ◽  
Work Up

Introduction: We developed a simple, fast and new method for the Fries rearrangement of aryl esters. Materials and Methods: 4-Hydroxy pyridinium triflate functionalized silica is a very efficient, reusable and economically available catalyst for the Fries rearrangement in solvent-free condition and under microwave irradiation. Results and Discussion: Also, a notable selectivity was observed in the presence of 4-hydroxy pyridinium triflate functionalized silica. Conclusion: Selectivity, shorter reaction time, high yield, and easy work-up are advantages of this synthetic method.

Eco-Friendly Synthesis of Sulphonic Acid Oxime Esters Catalyzed by 2-(1H-Benzotriazole-1-yl)-1,1,3,3-Tetramethyluronium Tetrafluoroborate

2014 ◽  
Vol 525 ◽  
pp. 93-96
Author(s):  
Wei Shi ◽  
Ji Ming Zhang ◽  
Jian Hua Zhou ◽  
Jian Hua Zhou ◽  
Song Song Ding
Keyword(s):  
High Selectivity ◽  
Sulphonic Acid ◽  
Present Approach ◽  
High Yield ◽  
Facile Synthesis ◽  
Reaction Duration ◽  
Mild Conditions ◽  
Environmental Friendly

Herein we describle a facile synthesis of sulphonic acid oxime esters in acetonitrile from the corresponding sulphonic acids and oximes catalyzed by the environmental friendly 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) in the presence of triethylamine (TEA) under mild conditions. The present approach offers the advantages of a clean reaction, simple methodology, employing readily available catalyst, short reaction duration, high selectivity and high yield.

Measured temperature and pressure dependence of Vp and Vs in compacted, polycrystalline sI methane and sII methane–ethane hydrate

2003 ◽  
Vol 81 (1-2) ◽  
pp. 47-53 ◽  
Author(s):  
M B Helgerud ◽  
W F Waite ◽  
S H Kirby ◽  
A Nur
Keyword(s):  
High Pressure ◽  
Shear Wave ◽  
Pressure Dependence ◽  
Gas Hydrate ◽  
Pressure Vessel ◽  
Wave Speed ◽  
Measured Temperature ◽  
Shear Wave Speed ◽  
Temperature And Pressure ◽  
Fixed End

We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane–ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17°C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between –20 and 15°C and 0 to 105 MPa applied piston pressure. PACS No.: 61.60Lj

Pretreatment of Fir Powder and Its Dissolution in Ionic Liquid of 1-(2-Hydroxylethyl)-3-Ethylene Imidazolium Chloride

2011 ◽  
Vol 236-238 ◽  
pp. 87-90
Author(s):  
Li Ying Guo
Keyword(s):  
High Pressure ◽  
Ionic Liquid ◽  
Dissolution Rate ◽  
Mass Fraction ◽  
Wood Powder ◽  
Imidazolium Chloride ◽  
Chemical Structures ◽  
Good Solubility ◽  
Temperature And Pressure ◽  
Pressure Dissolution

Ionic liquid, 1-(2-hydroxylethyl)-3-ethylene imidazolium chloride ([HeVIM]Cl) was synthesized and its chemical structures was examined by FTIR and 1HNMR. Fir powder was extracted with a mixture of benzene/ethanol or activated with 25% (mass fraction) NaOH under normal temperature and pressure, microwave and high pressure. Dissolution of the pretreated wood powder in [HeVIM]Cl by microwave (90°C, 400w) was studied. The results showed that the ionic liquid [HeVIM]Cl exhibited a good solubility. Wood powder pretreated with 25% NaOH under high pressure had the lowest crystallinity (2.4%) and the highest dissolution rate (21.6%).

HPHT synthesis and enhanced TE performance of Te and Sn/Se elements binary-doped CoSb3

2019 ◽  
Vol 12 (01) ◽  
pp. 1850105 ◽  
Author(s):  
Hairui Sun ◽  
Pin Lv ◽  
Chao Wang ◽  
Yunxian Liu ◽  
Xiaopeng Jia ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
High Pressure ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Grain Boundaries ◽  
Preparation Methods ◽  
Synthesis Time ◽  
Lattice Disorder ◽  
Positive Effect

A series of binary-doped CoSb3 with Te and Se/Sn bulk compounds Co4Sb[Formula: see text]TexSny/Sey ([Formula: see text] and 0.6, [Formula: see text] and 0.3), have been successfully prepared via a simple high pressure and high-temperature (HPHT) method. And, the influence of the doping elements on the microstructure of the samples synthesized under diverse pressures and the corresponding TE performance were studied in detail. Comparing with other preparation methods, the synthesis time of HPHT was acutely shortened. The obtained samples contain more grain boundaries, lattice disorder, dislocations and the possible “nanodot”, which have positive effect on reducing thermal conductivity. The experimental data indicate that the absolute values of Seebeck coefficient increases with pressure. What’s more, the thermal conductivities show a monotone decreasing trend as the synthesis pressure rises. The minimum value obtained is 1.93[Formula: see text]Wm[Formula: see text]K[Formula: see text] at normal temperature for Co4Sb[Formula: see text]Te[Formula: see text]Se[Formula: see text] prepared under 3[Formula: see text]GPa.

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