scholarly journals Novel Effect of Zinc Nitrate/Vanadyl Oxalate for Selective Catalytic Oxidation of α-Hydroxy Esters to α-Keto Esters with Molecular Oxygen: An In Situ ATR-IR Study

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1281 ◽  
Author(s):  
Yongwei Ju ◽  
Zhongtian Du ◽  
Chuhong Xiao ◽  
Xingfei Li ◽  
Shuang Li
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Aerobic Oxidation ◽  
Value Added ◽  
Attenuated Total Reflection ◽  
Reaction Conditions ◽  
Keto Esters ◽  
Selective Catalytic Oxidation ◽  
Hydroxy Esters

Selective oxidation of α-hydroxy esters is one of the most important methods to prepare high value-added α-keto esters. An efficient catalytic system consisting of Zn(NO3)2/VOC2O4 is reported for catalytic oxidation of α-hydroxy esters with molecular oxygen. Up to 99% conversion of methyl DL-mandelate or methyl lactate could be facilely obtained with high selectivity for its corresponding α-keto ester under mild reaction conditions. Zn(NO3)2 exhibited higher catalytic activity in combination with VOC2O4 compared with Fe(NO3)3 and different nitric oxidative gases were detected by situ attenuated total reflection infrared (ATR-IR) spectroscopy. UV-vis and ATR-IR results indicated that coordination complex formed in Zn(NO3)2 in CH3CN solution was quite different from Fe(NO3)3; it is proposed that the charge-transfer from Zn2+ to coordinated nitrate groups might account for the generation of different nitric oxidative gases. The XPS result indicate that nitric oxidative gas derived from the interaction of Zn(NO3)2 with VOC2O4 could be in favor of oxidizing VOC2O4 to generate active vanadium (V) species. It might account for different catalytic activity of Zn(NO3)2 or Fe(NO3)3 combined with VOC2O4. This work contributes to further development of efficient aerobic oxidation under mild reaction conditions.

Solvent-free liquid-phase selective catalytic oxidation of toluene to benzyl alcohol and benzaldehyde over CeO2-MnOx composite oxides

2022 ◽  
Author(s):  
Gui Chen ◽  
Kuiyi You ◽  
Xiangbo Gong ◽  
Fangfang Zhao ◽  
Zhenpan Chen ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Benzyl Alcohol ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Efficient Method ◽  
Value Added ◽  
Solvent Free ◽  
Composite Oxides ◽  
Selective Catalytic Oxidation

An efficient method for highly selective preparation of the high value-added benzyl alcohol (BOL) and benzaldehyde (BAL) from liquid-phase catalytic oxidation of toluene with molecular oxygen over CeO2-MnOx composite oxides...

Kinetic Model of the 1,2-Propanediol Oxidation Reaction in the Presence of 3wt%Pd/α-Al2O3 Catalyst

2021 ◽  
Vol 903 ◽  
pp. 143-148
Author(s):  
Svetlana Cornaja ◽  
Svetlana Zhizhkuna ◽  
Jevgenija Vladiko
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Kinetic Model ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Oxidation Reaction ◽  
Main Product ◽  
Oxidation Process ◽  
Water Solution ◽  
Reaction Conditions

Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c0(NaOH), p(O2), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.

scholarly journals Recent Advances in Homogeneous Metal-Catalyzed Aerobic C–H Oxidation of Benzylic Compounds

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 640 ◽  
Author(s):  
Garazi Urgoitia ◽  
Raul SanMartin ◽  
María Herrero ◽  
Esther Domínguez
Keyword(s):  
Molecular Oxygen ◽  
Aerobic Oxidation ◽  
Key Factors ◽  
Reaction Conditions ◽  
Aromatic Ketones ◽  
Recent Advances ◽  
Metal Catalyzed

Csp3–H oxidation of benzylic methylene compounds is an established strategy for the synthesis of aromatic ketones, esters, and amides. The need for more sustainable oxidizers has encouraged researchers to explore the use of molecular oxygen. In particular, homogeneous metal-catalyzed aerobic oxidation of benzylic methylenes has attracted much attention. This account summarizes the development of this oxidative strategy in the last two decades, examining key factors such as reaction yields, substrate:catalyst ratio, substrate scope, selectivity over other oxidation byproducts, and reaction conditions including solvents and temperature. Finally, several mechanistic proposals to explain the observed results will be discussed.

Selective aerobic allylic oxidation of α-pinene catalyzed by metalloporphyrins in the absence of solvents and additives

2019 ◽  
Vol 43 (9-10) ◽  
pp. 419-425 ◽  
Author(s):  
Huanhuan Dong ◽  
Shichao Xu ◽  
Jing Wang ◽  
Yuxiang Chen ◽  
Liangwu Bi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Flow Rate ◽  
Catalyst Concentration ◽  
Aerobic Oxidation ◽  
Oxygen Flow Rate ◽  
Oxidation Products ◽  
Allylic Oxidation ◽  
Temperature Reaction ◽  
Reaction Conditions

Selective aerobic oxidation of α-pinene to high-value products is a major challenge in chemistry. Metalloporphyrins are proved to be selective catalysts for aerobic oxidation of simple hydrocarbons. Herein, we extend this method to more complex substrates using metallodeuteroporphyrins as model catalysts. It was found that the oxidation occurs mainly on the C=C and allylic C–H bonds of α-pinene influenced by the reaction temperature, reaction time, catalyst concentration, and oxygen flow rate. Allylic C–H oxidation products are obtained with a maximum selectivity value of 78.4% using the following reaction conditions: 105°C, 7 h, 5 ppm, and 60 mL/min. The influence of the metal nuclei of the metallodeuteroporphyrins on this reaction is also investigated. It was found that metallodeuteroporphyrins with Fe3+ as the metal nucleus exhibit the highest catalytic activity.

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