scholarly journals Preparation of Propanols by Glycerol Hydrogenolysis over Bifunctional Nickel-Containing Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1565
Author(s):  
Alexander A. Greish ◽  
Elena D. Finashina ◽  
Olga P. Tkachenko ◽  
Leonid M. Kustov
Keyword(s):  
Reaction Temperature ◽  
Hydrogen Pressure ◽  
Heterogeneous Catalysts ◽  
Flow System ◽  
Total Yield ◽  
Optimal Combination ◽  
Glycerol Conversion ◽  
Mild Conditions ◽  
Glycerol Hydrogenolysis

The paper presents the results obtained in studying glycerol hydrogenolysis into 1-propanol and 2-propanol over bifunctional Ni/WO3-TiO2 and Ni/WO3-ZrO2 catalysts in the flow system. Due to the optimal combination of acidic and hydrogenation properties of the heterogeneous catalysts, they exhibit higher performance in glycerol conversion into C3 alcohols, although the process is carried out in rather mild conditions. At the reaction temperature of 250 °C and hydrogen pressure of 3 MPa, the total yield of 1-propanol and 2-propanol reaches 95%, and the glycerol conversion is close to 100%.

scholarly journals Hydrogenolysis of Glycerol over γ-Al2O3-Supported Iridium Catalyst

2017 ◽  
Vol 61 (4) ◽  
pp. 295
Author(s):  
Tamer S. Ahmed ◽  
Omar Y. Abdelaziz ◽  
George W. Roberts
Keyword(s):  
Hydrogen Pressure ◽  
Reaction Medium ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Solution Ph ◽  
Glycerol Conversion ◽  
The Sustainable Development ◽  
Iridium Catalyst ◽  
Glycerol Hydrogenolysis ◽  
Feed Volume

In recent years, much attention has been focused on the hydrogenolysis of biodiesel derived glycerol to other high value products for the sustainable development and efficient valorization strategies. In the present work, alumina-supported Ir catalyst was prepared by the incipient wetness impregnation method and tested in the glycerol hydrogenolysis reaction. The synthesized catalyst was characterized by neutron activation analysis, N2 physisorption, and H2 chemisorption techniques. The experiments standard conditions were 150 mL feed volume, 0.3 g catalyst, 1500 rpm stirring speed, and 5 wt% glycerol aqueous solution for 4 h. The effects of catalyst amount, temperature, hydrogen pressure, stirring speed, and solution pH on glycerol conversion and selectivity of the principal products obtained were also investigated. The glycerol conversion and the 1,2-propanediol selectivity varied from 4.9% to 22% and from 23.8% to 70.3%, respectively. It was found that the selectivity of 1,2-propanediol increased significantly with the increased alkalinity of the reaction medium.

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>

scholarly journals Glycerol Hydrogenolysis with In Situ Hydrogen Produced via Methanol Steam Reforming: The Promoting Effect of Pd on a Cu/ZnO/Al2O3 Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 110
Author(s):  
Yuanqing Liu ◽  
Chau T. Q. Mai ◽  
Flora T. T. Ng
Keyword(s):  
Steam Reforming ◽  
Catalyst Activity ◽  
Promoting Effect ◽  
Glycerol Conversion ◽  
Glycerol Hydrogenolysis ◽  
Glycerol Dehydration ◽  
Effect Of Pd ◽  
Al2o3 Catalyst ◽  
Reaction Equilibrium

The glycerol hydrogenolysis to produce 1,2-propanediol without using externally supplied hydrogen was investigated using methanol present in crude glycerol to provide in situ hydrogen via its steam reforming reaction. This paper focuses on the promoting effect of Pd on the reactivity of a Cu/Zn/Al2O3 catalyst. Adding 2 wt% Pd onto a Cu/ZnO/Al2O3 catalyst significantly improved the selectivity to 1,2-propanediol from 63.0% to 82.4% and the glycerol conversion from 70.2% to 99.4%. This enhancement on the catalytic activity by Pd is mainly due to the improved hydrogenation of acetol, which is the intermediate formed during the glycerol dehydration. The rapid hydrogenation of acetol can shift the reaction equilibrium of glycerol dehydration forward resulting in a higher glycerol conversion. The improved reducibility of the catalyst by Pd allows the catalyst to be reduced in situ during the reaction preventing any loss of catalyst activity due to any potential oxidation of the catalyst. The catalyst was slightly deactivated when it was firstly recycled resulting in a 5.4% loss of glycerol conversion due to the aggregation of Cu and the deactivation became less noticeable upon further recycling.

scholarly journals Continuous-Flow Processes for the Production of Floxacin Intermediates: Efficient C–C Bond Formation through a Rapid and Strong Activation of Carboxylic Acids

2020 ◽  
Vol 02 (03) ◽  
pp. e128-e132
Author(s):  
Shao-Zheng Guo ◽  
Zhi-Qun Yu ◽  
Wei-Ke Su
Keyword(s):  
Reaction Time ◽  
Continuous Flow ◽  
Flow System ◽  
Bond Formation ◽  
Product Yield ◽  
Raw Material ◽  
Material Consumption ◽  
Tank Reactor ◽  
Mild Conditions ◽  
Flow Processes

AbstractThe development of highly efficient C–C bond formation methods for the synthesis of ethyl 2-(2,4-dichloro-5-fluorobenzoyl)-3-(dimethylamino)acrylate 1 in continuous flow processes has been described, which is based on the concept of rapid and efficient activation of carboxylic acid. 2,4-Dichloro-5-fluorobenzoic acid is rapidly converted into highly reactive 2,4-dichloro-5-fluorobenzoyl chloride by treating with inexpensive and less-toxic solid bis(trichloromethyl)carbonate. And then it rapidly reacts with ethyl 3-(dimethylamino)acrylate to afford the desired 1. This process can be performed under mild conditions. Compared with the traditional tank reactor process, less raw material consumption, higher product yield, less reaction time, higher operation safety ensured by more the environmentally friendly procedure, and process continuity are achieved in the continuous-flow system.

Rhenium-promoted Pt/WO3/ZrO2: an efficient catalyst for aqueous glycerol hydrogenolysis under reduced H2 pressure

RSC Advances ◽  
2016 ◽  
Vol 6 (89) ◽  
pp. 86663-86672 ◽  
Author(s):  
Qing Tong ◽  
Anyi Zong ◽  
Wei Gong ◽  
Lei Yu ◽  
Yining Fan
Keyword(s):  
Catalyst Surface ◽  
Surface Acidity ◽  
Efficient Catalyst ◽  
Glycerol Conversion ◽  
Glycerol Hydrogenolysis

Re improved the dispersion of Pt in Pt/WO3/ZrO2 and enhanced the catalyst surface acidity. Pt–Re/WO3/ZrO2 afforded glycerol conversion >99% and C3 alcohol selectivity >95%. The reactions were performed under reduced H2 pressure.

scholarly journals Bi-functional heterogeneous catalysts for carbon dioxide conversion: enhanced performances at low temperature

RSC Advances ◽  
2018 ◽  
Vol 8 (45) ◽  
pp. 25342-25350 ◽  
Author(s):  
Adrien Comès ◽  
Xavier Collard ◽  
Luca Fusaro ◽  
Luciano Atzori ◽  
M. Giorgia Cutrufello ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Low Temperature ◽  
Reaction Temperature ◽  
Heterogeneous Catalysts ◽  
Cyclic Carbonates ◽  
Carbon Dioxide Conversion

Novel bi-functional catalysts allowing to decrease the reaction temperature for the synthesis of cyclic carbonates below 150 °C were successfully synthesized.

Pd/SiO2–AlPO4 systems. Influence of the preparation variables on their catalytic activity

1985 ◽  
Vol 63 (12) ◽  
pp. 3471-3477 ◽  
Author(s):  
A. Alba ◽  
M. A. Aramendia ◽  
V. Borau ◽  
C. Jimenez ◽  
J. M. Marinas
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Reaction Temperature ◽  
Hydrogen Pressure ◽  
Pd Catalysts ◽  
Metal Precursor ◽  
Preparation Conditions ◽  
Liquid Phase Hydrogenation ◽  
Initial Hydrogen Pressure ◽  
Catalyst Reduction

A study on the liquid phase hydrogenation of cyclohexene over a series of Pd catalysts supported on various SiO2–AlPO4 systems (using a concentration of 2.47 M, with methanol as solvent, the initial hydrogen pressure is 5 bar and reaction temperature 300 K) is reported in this paper. The reaction has been studied as a standard in order to determine the most suitable preparation conditions for these catalystsWe have also studied the influence of other factors such as the kind of support, the nature of the metal precursor, the previous calcination of the precursor, the addition of alkaline hydroxides, and the catalyst reduction with various agents, on the catalytic activity of different Pd-supported systems

scholarly journals Low Temperature Chemoselective Hydrogenation of Aldehydes over a Magnetic Pd Catalyst

2019 ◽  
Vol 9 (9) ◽  
pp. 1792
Author(s):  
Liu ◽  
Wang ◽  
Gao ◽  
Wang ◽  
Cheng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Heterogeneous Catalysts ◽  
Aromatic Aldehydes ◽  
Pd Catalyst ◽  
Primary Alcohols ◽  
Mild Conditions ◽  
Excellent Yield ◽  
Chemoselective Hydrogenation ◽  
Supported Palladium

Chemoselective hydrogenation of aldehydes with heterogeneous catalysts under mild conditions is of great importance but remains a major challenge. Herein, an efficient strategy was developed for low temperature chemoselective hydrogenation of aldehydes with broad substrate scope over a magnetic material supported palladium catalyst (γ-Fe2O3@HAP-Pd). Aldehydes bearing various reducible functional groups readily underwent hydrogenation to give the corresponding primary alcohols with moderate to excellent yield at room temperature in aqueous solutions. The Hammett equation revealed that the hydrogenation of aromatic aldehydes proceeded via an anionic intermediate. Additionally, when the temperature increased to 70 °C, toluene was obtained by the deoxygenation of benzaldehyde in excellent yield. Furthermore, the γ-Fe2O3@HAP-Pd could be recycled up to six times without loss of activity and metal leaching.

Chemical fixation of carbon dioxide catalyzed via covalent triazine frameworks as metal free heterogeneous catalysts without a cocatalyst

2019 ◽  
Vol 7 (45) ◽  
pp. 26071-26076 ◽  
Author(s):  
Yi-Meng Li ◽  
Li Yang ◽  
Lei Sun ◽  
Lei Ma ◽  
Wei-Qiao Deng ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Heterogeneous Catalysts ◽  
Chemical Fixation ◽  
Co Catalyst ◽  
Metal Free ◽  
Mild Conditions ◽  
Fixation Of Carbon Dioxide

2,5-DCP-CTF performs as an efficient metal-free catalyst in the chemical fixation of CO2 under mild conditions without the employment of any co-catalyst.

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