Synergistic effect of co-reactant promotes one-step oxidation of cyclohexane into adipic acid catalyzed by manganese porphyrins

2015 ◽  
Vol 93 (7) ◽  
pp. 696-701 ◽  
Author(s):  
Hui Li ◽  
Yuanbin She ◽  
Haiyan Fu ◽  
Meijuan Cao ◽  
Jing Wang ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Co Oxidation ◽  
Adipic Acid ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Catalyst Structure ◽  
Manganese Porphyrins ◽  
Co Oxidation Reaction ◽  
One Step ◽  
Acid Catalyzed

The synergistic effect of cyclohexane and cyclohexanone promoted synthesis of adipic acid catalyzed by [MnIIIT(p-Cl)PP]Cl with cyclohexane and cyclohexanone as co-reactants. The results showed that the conversions of cyclohexane and cyclohexanone were significantly enhanced because of the cyclohexanone synergistic effect, and the higher selectivity to adipic acid was obtained with dioxygen as an oxidant. The studies indicated that the co-oxidation of cyclohexane and cyclohexanone was influenced by the initial molar ratio of cyclohexanone and cyclohexane, catalyst structure, catalyst concentrations, and reaction conditions. The preliminary mechanism of the co-oxidation reaction of cyclohexane and cyclohexanone using [MnIIIT(p-Cl)PP]Cl as the catalyst was proposed.

scholarly journals Stroboscopic operando spectroscopy of the dynamics in heterogeneous catalysis by event-averaging

2021 ◽  
Author(s):  
Jan Knudsen ◽  
Tamires Gallo ◽  
Virgínia Boix ◽  
Marie Strømsheim ◽  
Giulio D'Acunto ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Oxidation Reaction ◽  
Ambient Pressure ◽  
Reaction Conditions ◽  
Catalyst Structure ◽  
Time Resolved ◽  
Co Oxidation Reaction ◽  
Surface Phases ◽  
Gas Environment

Abstract Heterogeneous catalyst surfaces are highly dynamic entities that respond rapidly to changes in their local gas environment, and the dynamics of the response is a decisive factor for the catalysts’ action and activity. Few probes are able to map catalyst structure and local gas environment simultaneously under reaction conditions at the time scales of the dynamic changes. Here we use the CO oxidation reaction over a Pd(100) surface exposed to pressures of 3 and 100 mbar of a CO + O2 gas mixture to demonstrate how such studies can be performed by time-resolved ambient pressure photoelectron spectroscopy. Central elements of the method are cyclic gas pulsing and software-based event-averaging by image recognition of spectral features. For the CO oxidation reaction over Pd(100) our main finding is that that all surface phases – the CO-covered Pd surface, a surface oxide and a thick PdOx phase – catalyse the CO oxidation reaction, in dependence on the supply of gas phase reactants.

scholarly journals Biodiesel Production from a Novel Nonedible Feedstock, Soursop (Annona muricata L.) Seed Oil

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2562 ◽  
Author(s):  
Chia-Hung Su ◽  
Hoang Nguyen ◽  
Uyen Pham ◽  
My Nguyen ◽  
Horng-Yi Juan
Keyword(s):  
Reaction Time ◽  
Seed Oil ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Annona Muricata ◽  
Reaction Conditions ◽  
Biodiesel Feedstock ◽  
Acid Catalyzed ◽  
American Society ◽  
Optimal Reaction

This study investigated the optimal reaction conditions for biodiesel production from soursop (Annona muricata) seeds. A high oil yield of 29.6% (w/w) could be obtained from soursop seeds. Oil extracted from soursop seeds was then converted into biodiesel through two-step transesterification process. A highest biodiesel yield of 97.02% was achieved under optimal acid-catalyzed esterification conditions (temperature: 65 °C, 1% H2SO4, reaction time: 90 min, and a methanol:oil molar ratio: 10:1) and optimal alkali-catalyzed transesterification conditions (temperature: 65 °C, reaction time: 30 min, 0.6% NaOH, and a methanol:oil molar ratio: 8:1). The properties of soursop biodiesel were determined and most were found to meet the European standard EN 14214 and American Society for Testing and Materials standard D6751. This study suggests that soursop seed oil is a promising biodiesel feedstock and that soursop biodiesel is a viable alternative to petrodiesel.

scholarly journals CO Oxidation on Stepped Rh Surfaces: μm-Scale Versus Nanoscale

2019 ◽  
Vol 150 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Y. Suchorski ◽  
I. Bespalov ◽  
J. Zeininger ◽  
M. Raab ◽  
M. Datler ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Reaction ◽  
Active Surface ◽  
Reaction Conditions ◽  
Miller Index ◽  
Co Oxidation Reaction ◽  
Catalytically Active ◽  
Field Emission Microscopy ◽  
Photoemission Electron

Abstract The catalytic CO oxidation reaction on stepped Rh surfaces in the 10−6 mbar pressure range was studied in situ on individual μm-sized high-Miller-index domains of a polycrystalline Rh foil and on nm-sized facets of a Rh tip, employing photoemission electron microscopy (PEEM) and field-ion/field-emission microscopy (FIM/FEM), respectively. Such approach permits a direct comparison of the reaction kinetics for crystallographically different regions under identical reaction conditions. The catalytic activity of the different Rh surfaces, particularly their tolerance towards poisoning by CO, was found to be strongly dependent on the density of steps and defects, as well as on the size (µm vs. nm) of the respective catalytically active surface. Graphic Abstract

scholarly journals Stroboscopic operando spectroscopy of the dynamics in heterogeneous catalysis by event-averaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jan Knudsen ◽  
Tamires Gallo ◽  
Virgínia Boix ◽  
Marie Døvre Strømsheim ◽  
Giulio D’Acunto ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Metallic Surface ◽  
Reaction Conditions ◽  
Catalyst Structure ◽  
Time Resolved ◽  
Poisoning Effect ◽  
Highly Active ◽  
Co Oxidation Reaction ◽  
Gas Environment

AbstractHeterogeneous catalyst surfaces are dynamic entities that respond rapidly to changes in their local gas environment, and the dynamics of the response is a decisive factor for the catalysts’ action and activity. Few probes are able to map catalyst structure and local gas environment simultaneously under reaction conditions at the timescales of the dynamic changes. Here we use the CO oxidation reaction and a Pd(100) model catalyst to demonstrate how such studies can be performed by time-resolved ambient pressure photoelectron spectroscopy. Central elements of the method are cyclic gas pulsing and software-based event-averaging by image recognition of spectral features. A key finding is that at 3.2 mbar total pressure a metallic, predominantly CO-covered metallic surface turns highly active for a few seconds once the O2:CO ratio becomes high enough to lift the CO poisoning effect before mass transport limitations triggers formation of a √5 oxide.

Preparation of Biodiesel from Crude Rubber Seed Oil by Alkaline Transesterification

2012 ◽  
Vol 581-582 ◽  
pp. 133-137
Author(s):  
Hong Wang ◽  
Yan Lin Sun ◽  
Li Zhang
Keyword(s):  
Fatty Acids ◽  
Yunnan Province ◽  
Seed Oil ◽  
Methyl Esters ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Rubber Seed Oil ◽  
Rubber Seed ◽  
Optimum Technique ◽  
Acid Catalyzed

Abstract: This paper is focused on the preparation of biodiesel from crude rubber seed oil with high free fatty acids (FFA) content. The rubber seeds were collected in Xishuangbanna, Yunnan province. Two-step synthesis was selected to obtain the product, that is, acid catalyzed esterification was carried out first to decrease the FFA content, then methyl esters of fatty acids can be formed by alkaline transesterification. The reaction conditions of alkaline transesterification were investigated. The results show that the optimum technique is to carry out the reaction at 60°C for 1.5h, with the methanol-to-oil molar ratio 6:1, the catalyst amount 1.0% (g NaOH/ g oil). The yield can reach 75%. GC analysis shows the content of methyl esters of fatty acids is 82.29%. Some properties of biodiesel prepared are also presented.

scholarly journals OPTIMIZING REACTION CONDITIONS OF BIODIESEL PRODUCTION FROM WASTE COOKING OIL USING GREEN SOLID CATALYST

2020 ◽  
Vol 7 (8) ◽  
pp. 65-71
Author(s):  
I Nengah Simpen ◽  
I Made Sutha Negara ◽  
Sofyan Dwi Jayanto
Keyword(s):  
Reaction Time ◽  
Research Result ◽  
Waste Cooking Oil ◽  
Biodiesel Production ◽  
National Standard ◽  
Molar Ratio ◽  
Solid Catalyst ◽  
Reaction Conditions ◽  
Cooking Oil ◽  
One Step

Biodiesel production from waste cooking oil in two steps reaction of esterification and transesterification is low efficient, due to twice methanol consumption and need more reaction time. Optimizing reaction conditions of CaO as a matrix of solid catalyst prepared from crab shell (green CaO) and modified by K2O/TiO2 for converting waste cooking oil to biodiesel have been carried out. Catalytic process of waste cooking oil to biodiesel took place in one step reaction of esterification and transesterification. The research result showed that optimum conditions in its one step reaction such as methanol to oil molar ratio was 9:1, amount of CaO/K2O-TiO2 catalyst to oil was 5% and reaction time of 60 minutes with biodiesel yield was 88.24%. Physical and chemical properties of biodiesel which produced from one step reaction of esterification and transesterification of waste cooking oil were suitable with Indonesian National Standard (SNI-04-7182-2006) namely density at 40oC of 850 kg/m3, kinematic viscosity at 40oC of 3.32 cSt, water content of 0.046%, iodine number of 59.25 g I2/100g and acid value of 0.29 mg KOH/g. Gas chromatography-mass spectrometry (GC-MS) analysis of biodiesel formed fatty acid methyl esters from conversion of waste cooking oil.

Esterification Deacidification of Zanthoxylum Bungeanum Seed Oil

2012 ◽  
Vol 512-515 ◽  
pp. 1615-1618
Author(s):  
Jian Zhang ◽  
Xuan Jun Wang
Keyword(s):  
Sulfuric Acid ◽  
Reaction Time ◽  
Seed Oil ◽  
Acid Value ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
One Step ◽  
Acid Catalyzed ◽  
Zanthoxylum Bungeanum ◽  
Acid Esterification

Effects of mole rate of methanol/oil, reaction time and technology on the free fatty acid ( FFA) level decrease of Zanthoxylum bungeanum seed oil with sulfuric acid as catalyst was investigated. Results show that, the acid level decreases with the mole rate of methanol/oil increases when the sulfuric acid is 2% based on the weight of Zanthoxylum bungeanum seed oil and reacting at 60°C for 2h. When the mole rate is 20~35∶1, the final acid value is less than 2mgKOH/g which meets the requirement for biodiesel production. When the mole rate is 25∶1, with sulfuric acid dosage 2% and reacting at 60°C, the acid value decreases fast at the beginning of the acid esterification. The acid value of ZSO was reduced to 1.56 mg KOH/g from 78.91 mg KOH/g by only one-step acid-catalyzed esterification with methanol-to-oil molar ratio 30:1, H2SO4 2%, temperature 60°C and reaction time 60 min, which was selected as optimum for the acid-catalyzed esterification.

scholarly journals Step dynamics and oxide formation during CO oxidation over a vicinal Pd surface

2016 ◽  
Vol 18 (30) ◽  
pp. 20312-20320 ◽  
Author(s):  
Mikhail Shipilin ◽  
Johan Gustafson ◽  
Chu Zhang ◽  
Lindsay Richard Merte ◽  
Edvin Lundgren
Keyword(s):  
Partial Pressure ◽  
Co Oxidation ◽  
Oxidation Reaction ◽  
Oxide Formation ◽  
Reaction Conditions ◽  
Co Oxidation Reaction ◽  
Step Dynamics

Under CO oxidation reaction conditions the surface of Pd(553) adopts different structures depending on O2 partial pressure.

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  
Keyword(s):  
Room Temperature ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Diastereoselective Synthesis ◽  
Substituted Anilines ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Acid Catalyzed ◽  
Reaction Media ◽  
Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

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