scholarly journals Selective Liquid Phase Hydrogenation of Benzaldehyde to Benzyl Alcohol Over Alumina Supported Gold

2019 ◽  
Vol 150 (3) ◽  
pp. 881-887
Author(s):  
Yufen Hao ◽  
Chiara Pischetola ◽  
Fernando Cárdenas-Lizana ◽  
Mark A. Keane
Keyword(s):  
Liquid Phase ◽  
Benzyl Alcohol ◽  
Reaction Conditions ◽  
Liquid Phase Hydrogenation ◽  
Alcohol Water ◽  
Reaction Constant ◽  
Supported Gold ◽  
First Time ◽  
Nucleophilic Mechanism ◽  
By Products

Abstract We report for the first time 100% benzyl alcohol yield from the liquid phase (T = 353 K, P = 9 bar) hydrogenation of benzaldehyde over Au/Al2O3. Under the same reaction conditions, a benchmark Pt/Al2O3 catalyst promoted the formation of toluene and benzene as hydrogenolysis by-products. Reaction kinetics was subjected to a Hammett treatment and the reaction constant (ρ = 0.9) was found to be consistent with a nucleophilic mechanism. A solvent (alcohol, water and alcohol + water) effect is demonstrated and ascribed to competitive adsorption where solvation by polar (water) facilitates benzaldehyde activation. Graphic Abstract

scholarly journals Liquid phase hydrogenation of CO2 to formate using palladium and ruthenium nanoparticles supported on molybdenum carbide

2019 ◽  
Vol 43 (35) ◽  
pp. 13985-13997 ◽  
Author(s):  
Claire E. Mitchell ◽  
Umberto Terranova ◽  
Ihfaf Alshibane ◽  
David J. Morgan ◽  
Thomas E. Davies ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Palladium Nanoparticles ◽  
Molybdenum Carbide ◽  
Active Catalyst ◽  
Ruthenium Nanoparticles ◽  
Reaction Conditions ◽  
Hydrogenation Of Co2 ◽  
Liquid Phase Hydrogenation ◽  
Hydrogenation Of Co

We report the development of palladium nanoparticles supported on Mo2C as an active catalyst for the liquid-phase hydrogenation of CO2 to formate under mild reaction conditions (100 °C and 2.0 MPa of a 1 : 1 CO2 : H2 mixture).

Catalytic Oxidation of Benzyl Alcohol to Benzaldehyde with Fe/Cu-Cross-Linked Montmorillonite

2011 ◽  
Vol 396-398 ◽  
pp. 1891-1894
Author(s):  
Xue Ju Zhang ◽  
He Song ◽  
Xiang Feng Guo ◽  
Li Hua Jia
Keyword(s):  
Hydrogen Peroxide ◽  
Liquid Phase ◽  
Benzyl Alcohol ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Reaction Conditions ◽  
Oxidation Of Benzyl Alcohol ◽  
Excellent Activity ◽  
Phase Oxidation

The Fe/Cu-cross-linked montmorillonite catalysts were synthesized with Linan Na-Mont and characterized by BET, SEM, XRD. Liquid-phase oxidation of benzyl alcohol to benzaldehyde by hydrogen peroxide over Fe/Cu-PILC catalyst in the absence of solvent has been thoroughly investigated. The influence of reaction conditions has also been studied. The results show that Fe/Cu(100)-PILC has excellent activity and reusability in the process. The active oxygen species in the reaction is from the absorbed oxygen of Fe/Cu-PILC.

scholarly journals INTENSIFICATION OF THE CYCLOHEXANE LIQUID PHASE OXIDATION PROCESS

2018 ◽  
Vol 13 (4) ◽  
pp. 50-57
Author(s):  
A. S. Frolov ◽  
E. A. Kurganova ◽  
E. M. Yarkina ◽  
N. V. Lebedeva ◽  
G. N. Koshel ◽  
...  
Keyword(s):  
Liquid Phase ◽  
High Selectivity ◽  
Fold Increase ◽  
Liquid Phase Oxidation ◽  
Oxidation Products ◽  
Additional Increase ◽  
Combined Use ◽  
Phase Oxidation ◽  
First Time ◽  
By Products

Liquid-phase oxidation of cyclohexane to cyclohexanol and cyclohexanone was studied in the absence of solvents under an air pressure of 0.5-5 MPa, in the temperature range 115-150 °C, catalyzed by N-hydroxyphthalimide (N-HPI). It was established for the first time that the use of N-HPI as a catalyst in place of the conventionally used metal salts of variable valence allowed a 2-3-fold increase in the conversion of the initial hydrocarbon and selectivity from 70-75 to 90%. The combined use of N-HPI with cobalt(II) acetate results in an additional increase in the conversion of cyclohexane by 30-40%, the selectivity of cyclohexanol and cyclohexanone formation to 94-97%, which seems to be due to the synergistic effect between the two components of the catalyst. The mechanism of catalytic oxidation of cyclohexane to cyclohexanol and cyclohexanone is discussed. It has been suggested that N-HPI plays a dual role in the oxidation of cyclohexane: it catalyzes the conversion of cyclohexane to cyclohexanol and cyclohexanone and, on the other hand, promotes the conversion of cyclohexanol to cyclohexanone, thereby substantially reducing the formation of adipic acid and its esters, by-products of the reaction, and increases selectivity of oxidation. This also explains the unusually high (1.3-1.5 : 1) ketone: alcohol ratio in the oxidation products of cyclohexane in the presence of N-HPI. The high selectivity of the formation of the desired products, the conversion of cyclohexane, the moderate temperature, the available catalyst, suggest that this method of oxidizing cyclohexane to cyclohexanol and cyclohexanone may be of interest for further practical use.

Nucleosides. III. Investigation of the Electrochemical Synthesis of N4, O5'-Diacetyl-2',3'-dideoxy-2',3'-didehydrocytidine

1994 ◽  
Vol 47 (10) ◽  
pp. 1843 ◽  
Author(s):  
O Johansen ◽  
SM Marcuccio ◽  
AWH Mau
Keyword(s):  
Current Density ◽  
Electrochemical Synthesis ◽  
Electrode Surface ◽  
Aprotic Solvents ◽  
Reaction Conditions ◽  
Protic Solvents ◽  
Half Wave ◽  
First Time ◽  
By Products ◽  
Base Moiety

The influence of the reaction conditions on the yield of N4,O5′-diacetyl-2′,3′-dideoxy-2′,3′-didehydrocytidine (3), by electrochemical synthesis from N4,O2′,O5′-triacetyl-3′-bromo-3′-deoxycytidine (2), has been studied in order to evaluate the potential of this reaction for synthesis on a larger scale. We have characterized the half-wave potentials of the precursor (2) and the product (3) by polarography under various conditions, and found that reduction in the base moiety can easily take place giving by-products. Furthermore, this reduction consumes protons leading to rapid solvolysis in protic solvents. We have demonstrated for the first time that (3) can be formed near quantitatively in both protic and aprotic solvents. The success of the synthesis of (3) as well as of other 2′,3′-dideoxy 2′,3′-didehydro nucleosides also depends to a large extent on how uniform the current density across the working electrode surface can be maintained during electrolysis.

scholarly journals Effect of Cerium Precursor in the Synthesis of Ce-MCM-41 and in the Efficiency for Liquid-Phase Oxidation of Benzyl Alcohol

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 377 ◽  
Author(s):  
Carlos M. Aiube ◽  
Karolyne V. de Oliveira ◽  
Julio L. de Macedo
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Benzyl Alcohol ◽  
Heterogeneous Catalysts ◽  
Liquid Phase Oxidation ◽  
Oxidation Of Benzyl Alcohol ◽  
Metal Precursors ◽  
Phase Oxidation ◽  
First Time ◽  
Mcm 41

Understanding the effects of synthetic parameters in the catalytic activity of heterogeneous catalysts is of utmost importance when aiming for optimal reaction conditions. Hence, we disclose in this work the synthesis and characterization of cerium-modified MCM-41 materials. In addition, it was observed for the first time, differences in catalytic activity when using different cerium synthetic precursors: CeCl3·7H2O and Ce(NO3)3·6H2O (Ce-MCM-Cl and Ce-MCM-NO3, respectively). A mechanism for cerium incorporation in MCM-41 was proposed, where [Ce(OH)3] species were hydrogen bonded to silicate anions, forming framework Ce-O-Si bonds during condensation and, consequently, causing distortion of the typical hexagonal mesophase. It was also observed that Ce(OH)3 formed aggregated layers with template assemblies during synthesis, resulting in non-framework CeO2 species on the MCM-41 surface after calcination. These CeO2 species were preferentially formed for Ce-MCM-NO3 and were attributed to the nitrate ions’ strong binding to template molecules. In the solvent free liquid-phase oxidation of benzyl alcohol (BzOH), Ce-MCM-Cl achieved better BzOH conversions and benzaldehyde (BzD) yields, while Ce-MCM-NO3 offered increased BzD selectivity. The catalysts’ reusability was also studied over three catalytic runs, where Ce-MCM-NO3 was more resistant than Ce-MCM-Cl towards deactivation. The observed catalytic behavior shows the importance of metal precursors in the obtainment of materials with desirable final properties.

Reaction Pathways and the Role of Solvent in the Hydrogenation of Chloronitrobenzenes

2003 ◽  
Vol 68 (10) ◽  
pp. 1819-1832 ◽  
Author(s):  
Vieroslav Krátky ◽  
Milan Králik ◽  
Alexander Kaszonyi ◽  
Magdaléna Stolcová ◽  
Lubomír Zalibera ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Benzene Ring ◽  
Catalyst Activity ◽  
Reaction Pathways ◽  
Reaction Conditions ◽  
Liquid Phase Hydrogenation ◽  
Role Of Solvent ◽  
Hplc Analyses ◽  
C Nmr

Liquid phase hydrogenation of chloronitrobenzenes to corresponding chloroanilines over Pd on carbon (Pd/C) under mild reaction conditions was studied. On the basis of 1H, 13C NMR, GC-MS and HPLC analyses of reaction mixtures, the reaction pathways were evaluated. The reduction of substrates proceeds via the formation of chloronitrosobenzenes and N-(chlorophenyl)hydroxylamines and mainly results in the formation of the chloroanilines and aniline. Aniline is formed by hydrogenolysis of chlorine (dechlorination) in benzene ring. Other compounds (mono- and disubstituted azobenzenes and azoxybenzenes) were also detected by GS-MS and HPLC (<3 mole %). The used solvent influences the reaction mixture composition and catalyst activity.

scholarly journals Liquid Phase Hydrogenation of Benzalacetophenone: Effect of Solvent, Catalyst Support, Catalytic Metal and Reaction Conditions

2011 ◽  
Vol 32 (6-8) ◽  
pp. 1312-1322 ◽  
Author(s):  
Achim STOLLE ◽  
Christine SCHMÖGER ◽  
Bernd ONDRUSCHKA ◽  
Werner BONRATH ◽  
Thomas F. KELLER ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Catalyst Support ◽  
Reaction Conditions ◽  
Effect Of Solvent ◽  
Liquid Phase Hydrogenation ◽  
Catalytic Metal
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