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.

Alkylation of Phenol with Cyclohexanol Catalyzed by Acidic Ionic Liquid

2011 ◽  
Vol 233-235 ◽  
pp. 188-193 ◽  
Author(s):  
Hai Bing Yu ◽  
Jun Nan ◽  
Jing Cheng Zhang ◽  
Jian Zhou Gui
Keyword(s):  
Ionic Liquid ◽  
Catalytic Activity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Reactant Ratio ◽  
Temperature Reaction ◽  
Reaction Conditions ◽  
Acidic Ionic Liquid ◽  
Optimum Reaction

Alkylation of phenol with cyclohexanol catalyzed by acidic ionic liquid has been investigated. The influences of reaction temperature, reaction time, reactant ratio (mol ratio of phenol to cyclohexanol), the amount and the recycle of ionic liquid on catalytic activity were studied. The conversion of phenol and the selectivity of paracyclohexylphenol were 75.5% and 61.6%, respectively, under optimum reaction conditions. The ionic liquid was utilized repeatedly over three times without remarkable loss of catalytic activity．

Effects of Reaction Conditions on Deposition of Ferrites from Alkaline Metal Hydroxide Gels

1997 ◽  
Vol 495 ◽  
Author(s):  
Karl F. Schoch ◽  
Theodore R. Vasilow
Keyword(s):  
Flow Rate ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Metal Hydroxides ◽  
X Ray ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Mg Content

ABSTRACTFormation of ferrites from aqueous solution of metal salts is a well known process involving precipitation of metal hydroxides followed by oxidation of the resulting gel. The purpose of the present work was to determine the effects oxygen flow rate on the progress of the reaction and on the structure and properties of the resulting precipitate. The reaction was carried out at 70°C with pH of 10.5 and oxygen flow rate of 2,4, or 8 standard liters per hour. The progress of the reaction was monitored by following the oxidation-reduction potential of the solution, which changes dramatically after the Fe(II) is consumed. The reaction rate increased with increasing oxygen flow rate. The Mg content of the precipitate was lower than that of the reaction mixture, possibly because of the pH of the reaction mixture. X-ray diffraction and infrared spectroscopy confirmed formation of a ferrite under these conditions.

Partition mechanism of adsorption and the absence of displacement phenomena in the zonal analytical chromatography of proteins on bead 2-hydroxy-3-phenoxypropyl-cellulose

1989 ◽  
Vol 54 (9) ◽  
pp. 2375-2385 ◽  
Author(s):  
Peter Gemeiner ◽  
Eva Hrabárová ◽  
Magdaléna Zacharová ◽  
Albert Breier ◽  
Milan J. Beneš
Keyword(s):  
Reaction Time ◽  
Perchloric Acid ◽  
Adsorption Mechanism ◽  
Spherical Shape ◽  
Molar Ratio ◽  
Temperature Reaction ◽  
Reaction Conditions ◽  
Hydrophobic Region ◽  
Bead Cellulose ◽  
To Come

Hydrophobization of bead cellulose is described, carried out by its alkylation with 1,2-epoxy-3-phenoxypropane under the conditions of acid (perchloric acid, borontrifluoride diethyl etherate) and basic (sodium hydroxide) catalysis. Reaction conditions (temperature, reaction time, molar ratio of reactants) have been determined, allowing the hydrophobization of bead cellulose to be carried out to the largest possible extent while maintaining its spherical shape. The nonstoichiometric mechanism suggested for the adsorption of amphiphilic adsorptives on bead 2-hydroxy-3-phenoxypropyl-cellulose (HPP-C) was checked by means of adsorption of six proteins. It was found that the surface of the hydrophobic segment of the adsorbent must be sufficiently large to be able to come in touch with the hydrophobic region of the protein through its multiple residues. In such cases the partitioning of the protein between the hydrophobic segment present as a liquid-like film and the surrounding solution becomes the predominant step of the adsorption. This adsorption mechanism is also reflected in zonal chromatography on bead HPP-C, as no displacement phenomena could be observed in any of the six proteins used. Retention of these proteins has been affected to a decisive extent by the degree of hydrophobization of HPP-C.

scholarly journals Hydrothermal Catalytic Conversion of Glucose into Lactic Acid with Acidic MIL-101(Fe)

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Xiaofang Liu ◽  
Zhigang Liu ◽  
Qiuyun Zhang ◽  
Hongguo Wu ◽  
Rui Wang
Keyword(s):  
Catalytic Activity ◽  
Lactic Acid ◽  
Reaction Time ◽  
Specific Surface ◽  
Catalytic Conversion ◽  
Temperature Reaction ◽  
Reaction Parameters ◽  
Acid Properties ◽  
Catalyst Reusability ◽  
First Time

MIL-101(Fe) was explored for the first time for the catalytic conversion of glucose into lactic acid (LA). The as-synthesized MIL-101(Fe) was successfully characterized, and its higher specific surface area, porosity, and feasible acid properties were confirmed to determine the remarkable catalytic activity in glucose-to-LA conversion (up to 25.4% yield) compared with other catalysts like MIL-101(Cr, Al) and UiO-66(Zr). The reaction parameters including temperature, reaction time, and substrate species as well as catalyst reusability were discussed.

Catalytic Synthesis of Benzyl Acetate by Diatomite Supported Waugh-Type (NH4)6[MnMo9O32] •8H2O

2013 ◽  
Vol 483 ◽  
pp. 38-41
Author(s):  
Shu Heng Liu
Keyword(s):  
Acetic Acid ◽  
Catalytic Activity ◽  
Reaction Time ◽  
Catalytic Synthesis ◽  
Orthogonal Test ◽  
Solid Catalyst ◽  
High Catalytic Activity ◽  
Benzyl Acetate ◽  
Reaction Conditions ◽  
Catalyst Dosage

Take Waugh-Type (NH4)6[MnMo9O32] •8H2O absorbed on diatomite and prepared supported solid catalyst. The properties of the catalyst were studied through the synthesis of benzyl acetate. The appropriate reaction conditions were obtained by orthogonal test: mole ratio of acetic acid to benzyl alcohol was 2.5:1.0, the catalyst dosage was 1.6g, the water carrying agent toluene dosage was 2.5ml, reaction time was 150min, esterification yield was 87.4%. The catalyst are high catalytic activity and non- polluting, and could be reused.

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.

Synthesis of Diethyl Carbonate from Ethyl Carbamate and Ethanol with Acid as Catalyst

2013 ◽  
Vol 821-822 ◽  
pp. 1081-1084 ◽  
Author(s):  
Xian Ye Qin ◽  
Biao Liu ◽  
Bing Han ◽  
Wen Bo Zhao ◽  
Shui Sheng Wu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Ethyl Carbamate ◽  
Diethyl Carbonate ◽  
Bronsted Acid ◽  
Optimal Conditions ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
Pyrophosphoric Acid

The catalytic activity of many Lewis and Bronsted acid for the synthesis of diethyl carbonate (DEC) from ethyl carbamate (EC) and ethanol was evaluated in a bath reactor. Pyrophosphoric acid (H4P7O2) which showed the best activity was selected to further investigate the effect of reaction conditions, such as reaction temperature, catalyst dose and reaction time, on the yield of DEC. Under the optimal conditions, DEC yield can reach 29.1%.

scholarly journals High Oleic Pentaerythritol Tetraester Formation via Transesterification: Effect of Reaction Conditions

2020 ◽  
Vol 20 (4) ◽  
pp. 887 ◽  
Author(s):  
Nor Faeqah Idrus ◽  
Robiah Yunus ◽  
Zurina Zainal Abidin ◽  
Umer Rashid ◽  
Norazah Abd Rahman
Keyword(s):  
Reaction Time ◽  
Methyl Ester ◽  
Sodium Methoxide ◽  
Catalyst Concentration ◽  
Vacuum Pressure ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
High Oleic ◽  
Operating Variables ◽  
The Ideal

Pentaerythritol tetraoleate esters synthesized from high oleic palm oil methyl ester (POME) have potential as biolubricant base stock. In the present study, the chemical transesterification of POME and pentaerythritol (PE) using sodium methoxide as a catalyst was conducted under vacuum. The effect of operating variables such as reaction temperature, catalyst concentration, the molar ratio of POME to PE, vacuum pressure, and stirring rate on the yield of PE tetraoleate was examined. The ideal conditions for the reaction were at a temperature of 160 °C, 1.25% (w/w) catalyst concentration, the molar ratio of POME to PE at 4.5:1, vacuum pressure at 10 mbar, and stirring speed at 900 rpm. PE tetraoleate with a yield of 36% (w/w), was successfully synthesized under this condition within 2 h of reaction time.

Magnesium Recovery from Desiliconization Slag of Nickel Laterite Ores by Carbonization

2013 ◽  
Vol 813 ◽  
pp. 255-258 ◽  
Author(s):  
Wen Ning Mu ◽  
Shuang Zhi Shi ◽  
Yu Chun Zhai
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Flow Rate ◽  
Temperature Reaction ◽  
Nickel Laterite ◽  
Experimental Conditions ◽  
Solid Ratio ◽  
Carbonation Process ◽  
Laterite Ores ◽  
Orthogonal Experiments

This work examines the recovery of magnesium from desiliconization slag of nickel laterite ores by carbonation process. The effects of reaction temperature, reaction time, liquid/solid ratio and CO2 flow rate on magnesium dissolution are investigated. The optimized experimental conditions of recovering magnesium were gained by the analysis of orthogonal experiments.

Nanoaggregates of Mn(III)tetraperfluorophenylporphyrin: a greener approach for allylic oxidation of olefins

2011 ◽  
Vol 15 (11n12) ◽  
pp. 1258-1264 ◽  
Author(s):  
Amit Aggarwal ◽  
Sunaina Singh ◽  
Charles M. Drain
Keyword(s):  
Catalytic Activity ◽  
Molecular Oxygen ◽  
Reaction Medium ◽  
Oxidation Products ◽  
Allylic Oxidation ◽  
Central Metal Atom ◽  
Central Metal ◽  
Organic Nanoparticles ◽  
Aqueous Solvent ◽  
Turn Over

Organic nanoparticles of metalloporphyrins can be a versatile catalyst for the selective oxidation of alkenes and other hydrocarbons. The catalytic activity of the metalloporphyrin depends on the nature of the central metal atom, peripheral groups, and the architecture of the porphyrin macrocycle. Herein, we report the catalytic activity of organic nanoparticles of 5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)porphyrinato manganese(III), Mn (III)TPPF20, for the oxidation of cyclohexene using molecular oxygen as an oxidant in aqueous solvent under ambient conditions. While the solvated metalloporphyrins catalytically oxidize alkenes to the corresponding epoxide with a modest turn-over numbers, ca. 30 nm organic nanoparticles of Mn (III)TPPF20 have enhanced catalytic activity with up to a two-fold greater turn-over number and yields only allylic oxidation products. The activity of organic nanoparticles is slow compared to the solvated metalloporphyrins. These organic nanoparticles catalytic systems facilitate a greener reaction since ca. 89% of the reaction medium is water, molecular oxygen is used in place of man-made oxidants, and the ambient reaction conditions require less energy. This organic nanoparticle catalytic system also avoids using halogenated solvents commonly used in solution phase reactions. The enhanced catalytic activity of these organic nanoparticles is unexpected because the metalloporphyrins in the nanoaggregates are in the close proximity and the turn-over number should diminish by self-oxidative degradation.

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