Preparation and characterization of copper chloride supported on citric acid-modified magnetite nanoparticles (Cu2+ -CA@Fe3 O4 ) and evaluation of its catalytic activity in the reduction of nitroarene compounds

2017 ◽  
Vol 31 (12) ◽  
pp. e3822 ◽  
Author(s):  
Ehsan Ghonchepour ◽  
Elahe Yazdani ◽  
Dariush Saberi ◽  
Marzban Arefi ◽  
Akbar Heydari
Keyword(s):  
Catalytic Activity ◽  
Citric Acid ◽  
Magnetite Nanoparticles ◽  
Copper Chloride

Synthesis, Characterization of Novel Hexamethyleneiminium-Based Ionic Liquids and their Application in Esterification

2011 ◽  
Vol 233-235 ◽  
pp. 155-159
Author(s):  
Gong Li ◽  
Fei Ke Wu ◽  
Hui Juan Tong
Keyword(s):  
Catalytic Activity ◽  
Ionic Liquids ◽  
Citric Acid ◽  
Hydrogen Sulfate ◽  
Catalytic Activities ◽  
H Nmr ◽  
Acidic Ionic Liquids ◽  
Ft Ir

Three novel Brønsted acidic ionic liquids (ILs), 1-(3-sulfopropyl) hexamethyleneiminium hydrogen sulfate ([HMIPS]HSO4), 1-(3-sulfopropyl) hexamethyleneiminium tosilate ([HMIPS]OTs) and 1-hexamethyleneiminium hydrogen sulfate([HMI]HSO4), were synthesized and characterized by1H NMR, FT-IR and DSC-TG. Their catalytic activities for the esterification of citric acid with n-butanol were examined and compared with the imidazolium-based ILs. The results showed that the hexamethyleneiminium-based ILs exhibits excellent catalytic activity. By using [HMIPS]HSO4as the catalyst, the yield of tributyl citrate reached 97.5%. Furthermore, the catalysts were reused at least 10 times without significant decrease in activity

scholarly journals Characterization of Phosphate Coatings: Influence of the Acid Pickling Conditions

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1048
Author(s):  
Belén Díaz ◽  
X. Ramón Nóvoa ◽  
Carmen Pérez ◽  
Sheila Silva-Fernández
Keyword(s):  
Citric Acid ◽  
High Strength ◽  
Acid Pickling ◽  
Acid Cleaning ◽  
Inorganic Acids ◽  
Phosphate Coatings ◽  
Acid Bath ◽  
Coating Morphology ◽  
Coating Weight

This research emphasizes the importance of the acid cleaning prior to the phosphate development on high-strength steel rods. It compares the phosphate properties achieved after different acid-pickling conditions. The most common inorganic acids were considered in this study. Additionally, taking into account the environmental and safety concerns of these acids, the assessment of a less harmful organic acid is presented. This study revealed significant differences in the coating morphology and chemical composition whereas no great changes were found in terms of the coating weight or porosity. Thus, hydrochloric and sulfuric acid promote the growth of a Fe-enriched phosphate layer with a less conductive character that is not developed after the pickling with phosphoric acid. The phosphate developed after the citric acid pickling is comparable to that developed after the inorganic acids although with a porosity slightly higher. The temperature of the citric acid bath is an important parameter that affects to the phosphate appearance, composition, and porosity.

scholarly journals Structural Characterization of a Polysaccharide from Gastrodia elata and Its Bioactivity on Gut Microbiota

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4443
Author(s):  
Jiangyan Huo ◽  
Min Lei ◽  
Feifei Li ◽  
Jinjun Hou ◽  
Zijia Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Citric Acid ◽  
Gut Microbiota ◽  
Structural Characterization ◽  
Hot Water ◽  
Nmr Analysis ◽  
Gastrodia Elata ◽  
Hot Water Extraction ◽  
Hydroxybenzyl Alcohol

A novel homogeneous polysaccharide named GEP-1 was isolated and purified from Gastrodia elata (G. elata) by hot-water extraction, ethanol precipitation, and membrane separator. GEP-1, which has a molecular weight of 20.1 kDa, contains a polysaccharide framework comprised of only glucose. Methylation and NMR analysis showed that GEP-1 contained 1,3,6-linked-α-Glcp, 1,4-linked-α-Glcp, 1,4-linked-β-Glcp and 1,4,6-linked-α-Glcp. Interestingly, GEP-1 contained citric acid and repeating p-hydroxybenzyl alcohol as one branch. Furthermore, a bioactivity test showed that GEP-1 could significantly promote the growth of Akkermansia muciniphila (A. muciniphila) and Lacticaseibacillus paracasei (L.paracasei) strains. These results implied that GEP-1 might be useful for human by modulating gut microbiota.

scholarly journals Synthesis, Characterization of Chitosan-Aluminum Oxide Nanocomposite for Green Synthesis of Annulated Imidazopyrazol Thione Derivatives

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1160
Author(s):  
Abir S. Abdel-Naby ◽  
Sara Nabil ◽  
Sarah Aldulaijan ◽  
Ibtisam M. Ababutain ◽  
Azzah I. Alghamdi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Aluminum Oxide ◽  
Reaction Medium ◽  
Thiol Group ◽  
Docking Studies ◽  
Significant Loss ◽  
Gram Negative Bacteria ◽  
Organic Catalyst ◽  
Group 1

Chitosan-aluminum oxide nanocomposite was synthesized, characterized, and used as a green heterogeneous catalyst to synthesize novel imidazopyrazolylthione derivatives. Nanocomposite polymeric material was characterized by EDS-SEM and XRD. The powerful catalytic activity, and its base character of the nanocomposite, was used to synthesize imidazopyrazolylthione (1) in a good yield compared to traditional cyclocondensation synthesis. Using the nanocomposite catalyst, substitution of the thiol group (1) afforded the corresponding thiourea (2) and the corresponding ester (3). The efficiency of the nanocomposite over the traditional base organic catalyst, Et3N and NaOH, makes it an effective, economic, and reproducible nontoxic catalyst. Moreover, the heterogeneous nanocomposite polymeric film was easily isolated from the reaction medium, and recycled up to four times, without a significant loss of its catalytic activity. The newly synthesized derivatives were screened as antibacterial agents and showed high potency. Molecular docking was also performed for a more in-depth investigation. The results of the docking studies have demonstrated that the docked compounds have strong interaction energies with both Gram-positive and Gram-negative bacteria.

scholarly journals Tyrosinase Nanoparticles: Understanding the Melanogenesis Pathway by Isolating the Products of Tyrosinase Enzymatic Reaction

2021 ◽  
Vol 22 (2) ◽  
pp. 734
Author(s):  
Paul K. Varghese ◽  
Mones Abu-Asab ◽  
Emilios K. Dimitriadis ◽  
Monika B. Dolinska ◽  
George P. Morcos ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Large Scale ◽  
Magnetic Beads ◽  
Enzymatic Reaction ◽  
Oculocutaneous Albinism ◽  
Transmission Electron ◽  
Hill Kinetics ◽  
Rate Limiting ◽  
Human Tyrosinase

Human Tyrosinase (Tyr) is the rate-limiting enzyme of the melanogenesis pathway. Tyr catalyzes the oxidation of the substrate L-DOPA into dopachrome and melanin. Currently, the characterization of dopachrome-related products is difficult due to the absence of a simple way to partition dopachrome from protein fraction. Here, we immobilize catalytically pure recombinant human Tyr domain (residues 19–469) containing 6xHis tag to Ni-loaded magnetic beads (MB). Transmission electron microscopy revealed Tyr-MB were within limits of 168.2 ± 24.4 nm while the dark-brown melanin images showed single and polymerized melanin with a diameter of 121.4 ± 18.1 nm. Using Hill kinetics, we show that Tyr-MB has a catalytic activity similar to that of intact Tyr. The diphenol oxidase reactions of L-DOPA show an increase of dopachrome formation with the number of MB and with temperature. At 50 °C, Tyr-MB shows some residual catalytic activity suggesting that the immobilized Tyr has increased protein stability. In contrast, under 37 °C, the dopachrome product, which is isolated from Tyr-MB particles, shows that dopachrome has an orange-brown color that is different from the color of the mixture of L-DOPA, Tyr, and dopachrome. In the future, Tyr-MB could be used for large-scale productions of dopachrome and melanin-related products and finding a treatment for oculocutaneous albinism-inherited diseases.

Characterization of a novel carboxylesterase with catalytic activity toward di(2-ethylhexyl) phthalate from a soil metagenomic library

2021 ◽  
Vol 785 ◽  
pp. 147260
Author(s):  
Zhenzhen Yan ◽  
Liping Ding ◽  
Dandan Zou ◽  
Jiarong Qiu ◽  
Yuting Shao ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metagenomic Library ◽  
Ethylhexyl Phthalate

scholarly journals Synthesis and Magnetic Characterization of Graphite-Coated Iron Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
A. M. Espinoza-Rivas ◽  
M. A. Pérez-Guzmán ◽  
R. Ortega-Amaya ◽  
J. Santoyo-Salazar ◽  
C. D. Gutiérrez-Lazos ◽  
...  
Keyword(s):  
Magnetite Nanoparticles ◽  
Iron Nanoparticles ◽  
Vapour Deposition ◽  
Magnetic Measurements ◽  
Chemical Vapour ◽  
Hydrogen Atmosphere ◽  
Iron Core ◽  
Carbon Excess ◽  
Raman Characterization

Graphite-coated iron nanoparticles were prepared from magnetite nanoparticles by chemical vapour deposition (CVD) under methane and hydrogen atmosphere. After being purified from carbon excess, graphite-coated iron nanoparticles were tested for morphological and magnetic properties. It was found that, during the thermal process, magnetite nanoparticles 6 nm in size coalesce and transform into graphite-coated iron 200 nm in size, as revealed by scanning electron microscopy (SEM). Raman characterization assessed that high-quality graphite coats the iron core. Magnetic measurements revealed the phase change (magnetite to iron) as an increase in the saturation magnetization from 50 to 165 emu/g after the CVD process.

Synthesis and characterization of highly ordered MCM-41 in an alkali-free system and its catalytic activity

1996 ◽  
Vol 38 (1-2) ◽  
pp. 33-37 ◽  
Author(s):  
Xiu S. Zhao ◽  
Gao Q. Lu ◽  
Graeme J. Millar ◽  
Xin S. Li
Keyword(s):  
Catalytic Activity ◽  
Synthesis And Characterization ◽  
Free System ◽  
Mcm 41

Synthesis and characterization of magnetically recyclable Ag nanoparticles immobilized on Fe3O4@C nanospheres with catalytic activity

2015 ◽  
Vol 335 ◽  
pp. 23-28 ◽  
Author(s):  
Wei-hong Li ◽  
Xiu-ping Yue ◽  
Chang-sheng Guo ◽  
Jia-pei Lv ◽  
Si-si Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Ag Nanoparticles ◽  
Synthesis And Characterization
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