scholarly journals Hydrogenation of Adiponitrile to Hexamethylenediamine over Raney Ni and Co Catalysts

2020 ◽  
Vol 10 (21) ◽  
pp. 7506 ◽  
Author(s):  
Younghyun Lee ◽  
Sung Woo Lee ◽  
Hyung Ju Kim ◽  
Yong Tae Kim ◽  
Kun-Yi Andrew Lin ◽  
...  
Keyword(s):  
Metal Leaching ◽  
Catalyst Loading ◽  
Ni Catalyst ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Raney Ni ◽  
Higher Temperature ◽  
Product Solution

Hexamethylenediamine (HMDA), a chemical for producing nylon, was produced on Raney Ni and Raney Co catalysts via the hydrogenation of adiponitrile (ADN). HMDA was hydrogenated from ADN via 6-aminohexanenitrile (AHN). For the two catalysts, the effects of five different reaction parameters (reaction temperature, H2 pressure, catalyst loading, and ADN/HMDA ratio in the reactant) on the hydrogenation of ADN were investigated. Similar general trends demonstrating the dependence of ADN hydrogenation on the reaction conditions for both catalysts were observed: higher temperature (60–80 °C) and H2 pressure, as well as lower ADN/catalyst and ADN/HMDA ratios, led to higher HMDA yields. A further increase in temperature from 80 to 100 °C increased the HMDA yield from 90.5 to 100% for the Raney Ni catalyst, but did not affect the HMDA yield (85~87%) for the Raney Co catalyst. A 100% HMDA yield (the highest yield reported to date) was also achieved via ADN hydrogenation over the Raney Ni catalyst, with a high HMDA content in the reactant (e.g., ADN/HMDA volumetric ratio of 0.06). No sign of metal leaching into the product solution was found, meaning that the Raney Ni and Raney Co catalysts were stable during ADN hydrogenation.

scholarly journals Sustainable Highly Selective Toluene Oxidation to Benzaldehyde

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 262
Author(s):  
Francesca Valentini ◽  
Giacomo Ferracci ◽  
Pierluca Galloni ◽  
Giuseppe Pomarico ◽  
Valeria Conte ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Synthetic Route ◽  
Reaction Conditions ◽  
Toluene Oxidation ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Hydrophobic Ionic Liquids ◽  
Industrial Level ◽  
Oxidative System

Thanks to the well-recognized role of benzaldehyde in industry, nowadays the research of new and sustainable approaches to selectively synthesize such an interesting product is receiving great attention from the chemists’ community. In this paper, a V-based catalytic biphasic system is adopted to perform toluene oxidation to benzaldehyde. Importantly, to pursue sustainability, organic solvents have been avoided, so toluene is used as substrate and co-solvent, together with water. Also, the use of hydrophobic ionic liquids has been explored. To perform oxidation, NH4VO3 catalyst, H2O2, and a safe and inexpensive co-catalyst are used. Among the tested co-catalysts, KF and O2 were found to be the best choice, to guarantee good yields, in mild reaction conditions. In fact, with such a sustainable method, up to 30% of benzaldehyde can be obtained at 60 °C and, more interestingly, the oxidative system can be recharged, raising-up the yield. The entire process results highly selective, since no traces of benzyl alcohol or benzoic acid are detected. Hence, it constitutes a very appealing synthetic route, even suitable to be easily scaled-up at an industrial level.

scholarly journals Influence of Co-Catalysts and Polymerization Conditions on Properties of Poly(anhydride-alt-epoxide)s from ROCOP Using Salen Complexes with Different Metals

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1222 ◽  
Author(s):  
Proverbio ◽  
Galotto ◽  
Losio ◽  
Tritto ◽  
Boggioni
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Reaction Conditions ◽  
Aliphatic Polyesters ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Salen Complexes ◽  
Polymerization Conditions

Cyclohexene oxide (CHO) and phthalic anhydride (PA) have been reacted in the presence of commercial salen–type complexes with different metals Cr (1), Al (2), and Mn (3) in combination with 4-(dimethylamino) pyridine (DMAP), bis-(triphenylphosphorydine) ammonium chloride (PPNCl) and bis-(triphenylphosphoranylidene)ammonium azide (PPNN3) as co-catalysts to obtain alternating poly(PA-alt-CHO)s by ring-opening copolymerization (ROCOP). The effect of different reaction conditions (pre-contact between catalyst and co-catalyst, polymerization time) on the productivity, molecular weight and glass transition temperature has been evaluated. By using a 24 h pre-contact, the aliphatic polyesters obtained were characterized by high molecular weight (Mn > 15 kg/mol) and glass transition temperature (Tg) up to 146 °C; the more sustainable metals Al and Mn in the presence of PPNCl give comparable results to Cr. Moreover, biodegradability data of these polyesters and the study of the microstructure reveal that the biodegradability is influenced more by the type of chain linkages rather than by the molecular weight of the polyesters.

scholarly journals Catalytic condensation of depithed sugarcane bagasse derived levulinic acid into diphenolic acid

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2235-2248
Author(s):  
Lethiwe Debra Mthembu ◽  
David Lokhat ◽  
Nirmala Deenadayalu
Keyword(s):  
Sulfuric Acid ◽  
Sugarcane Bagasse ◽  
Levulinic Acid ◽  
Methanesulfonic Acid ◽  
Environmentally Benign ◽  
Catalyst Loading ◽  
Optimum Conditions ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
Catalytic Condensation

Levulinic acid (LA) is a platform chemical that can be produced from biomass. Diphenolic acid (DPA) is a derivative of LA with the potential to replace bisphenol A, a plasticizer. To determine the optimum conditions for DPA production, commercial LA was used with a mild environmentally benign acid, namely, methanesulfonic acid (MsOH). The optimized reaction parameters were time (6 h), temperature (75 °C), and catalyst loading (5.5 g), yielding 65.8% DPA at 90% LA conversion. The response surface methodology (RSM) study indicated that the temperature had the most significant effect on DPA yield, followed by time and catalyst loading. The analysis of variance (ANOVA) revealed that the model was able to satisfactorily predict the DPA yield. To determine the effect of catalyst on DPA production from commercial LA, ionic liquids (ILs), MsOH, and sulfuric acid were used. IL catalysts produced 59 to 68% of DPA, MsOH produced 65.6% of DPA, and sulfuric acid produced the maximum DPA of 74%. The study of LA: phenol ratio revealed that more reactants (2:5) yielded the most DPA (86.35%). The optimized reaction conditions were then used to produce DPA from LA derived from depithed sugarcane bagasse (DSB), which yielded 64.5% of DPA.

Surfactant involved in Copper Sulfide Nanocrystallites Synthesis

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Claudia Maria Simonescu ◽  
Valentin Serban Teodorescu ◽  
Camelia Capatina
Keyword(s):  
Copper Sulfide ◽  
X Ray Diffraction ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Shape Of Nanoparticles ◽  
Tem Transmission Electron Microscopy ◽  
Shape And Size

This paper presents the obtaining of copper sulfide CuS (covelite) from Cu(CH3COO)2.H2O and thioacetamide (TAA) system. The reaction was conducted in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). The effects of various reaction parameters on the size and on the shape of nanoparticles have been examined. CuS obtained was characterized by X ray diffraction, IR spectroscopy, TEM � transmission electron microscopy and SAED selected area electron diffraction. The influence of surfactant to the shape and size of CuS (covellite) nanocrystals was established. The size of the nanocrystals varied from 10-60 nm depending on the reaction conditions such as quantity of surfactant.

A review of sustainable lignocellulose biorefining applying (natural) deep eutectic solvents (DESs) for separations, catalysis and enzymatic biotransformation processes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ana Bjelić ◽  
Brigita Hočevar ◽  
Miha Grilc ◽  
Uroš Novak ◽  
Blaž Likozar
Keyword(s):  
Special Section ◽  
Cost Effective ◽  
Deep Eutectic Solvents ◽  
Reaction Conditions ◽  
Co Catalysts ◽  
Biomass Fractionation ◽  
Functional Step ◽  
Natural Deep Eutectic Solvents ◽  
Economic Need ◽  
Molecular Compounds

AbstractConventional biorefinery processes are complex, engineered and energy-intensive, where biomass fractionation, a key functional step for the production of biomass-derived chemical substances, demands industrial organic solvents and harsh, environmentally harmful reaction conditions. There is a timely, clear and unmet economic need for a systematic, robust and affordable conversion method technology to become greener, sustainable and cost-effective. In this perspective, deep eutectic solvents (DESs) have been envisaged as the most advanced novel polar liquids that are entirely made of natural, molecular compounds that are capable of an association via hydrogen bonding interactions. DES has quickly emerged in various application functions thanks to a formulations’ simple preparation. These molecules themselves are biobased, renewable, biodegradable and eco-friendly. The present experimental review is providing the state of the art topical overview of trends regarding the employment of DESs in investigated biorefinery-related techniques. This review covers DESs for lignocellulosic component isolation, applications as (co)catalysts and their functionality range in biocatalysis. Furthermore, a special section of the DESs recyclability is included. For DESs to unlock numerous new (reactive) possibilities in future biorefineries, the critical estimation of its complexity in the reaction, separation, or fractionation medium should be addressed more in future studies.

Y(OTf)3-catalyzed Phosphorylation of 2H-Chromene Hemiacetals with P(O)-H compounds to 2-Phosphorylated 2H-Chromenes

2021 ◽  
Author(s):  
Long Chen ◽  
Shi-Lu Zheng ◽  
Yun-Xiang Zou ◽  
Zhong Wen ◽  
Jiafu Lin ◽  
...  
Keyword(s):  
Catalyst Loading ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
Low Catalyst Loading

Facile synthesis of 2-phosphorylated 2H-chromenes has been accomplished herein via a Y(OTf)3-catalyzed dehydrative coupling of 2H-chromene hemiacetals with P(O)-H compounds. This protocol features low catalyst loading, mild reaction conditions, broad...

Preparation and Characrization of Tic/C Composite Fiber by Chemical Vapor Deposition

2012 ◽  
Vol 455-456 ◽  
pp. 935-938
Author(s):  
Hai Quan Wang
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Fibers ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Composite Fiber ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Tic Particle ◽  
Higher Temperature

- TiC/C composite fibers were prepared by vapor phase titanizing of the regular carbon fibers via chemical vapor deposition (CVD). The carbon fibers were titanized from the surface of the fiber to the core. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were applied to characterize the morphology and structure of the TiC/C composite fibers. The influences of CVD reaction conditions such as temperature and reaction time on the TiC particle size and the thickness of the deposited layer were investigated. Higher temperature and longer time resulted in the growth of bigger size of the TiC crystal particles, and the particle uniformity was also decreased.

scholarly journals Photocatalytic reduction of CO2 over exposed-crystal-face-controlled TiO2 nanorod having a brookite phase with co-catalyst loading

2014 ◽  
Vol 152-153 ◽  
pp. 309-316 ◽  
Author(s):  
Teruhisa Ohno ◽  
Takayoshi Higo ◽  
Naoya Murakami ◽  
Hirofumi Saito ◽  
Qitao Zhang ◽  
...  
Keyword(s):  
Photocatalytic Reduction ◽  
Catalyst Loading ◽  
Crystal Face ◽  
Co Catalyst ◽  
Tio2 Nanorod ◽  
Reduction Of Co2 ◽  
Brookite Phase
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