scholarly journals Heterogeneization of alpha diimines nickel catalysts for the polymerization of ethylene and methylmethacrylate

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Inês Matos ◽  
Auguste Fernandes ◽  
Rita Catalão ◽  
Ana M. Botelho do Rego ◽  
José R. Ascenso ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Cation ◽  
Organometallic Compound ◽  
Heterogeneous Catalysts ◽  
Active Catalyst ◽  
Organic Ligand ◽  
Nickel Catalysts ◽  
Organometallic Complex ◽  
The One

AbstractIn this paper we present two different techniques for the preparation of single site heterogeneous catalyst. The first method consists in the impregnation of a solution of the organometallic compound in MCM41. The second method intends to establish the in situ synthesis of the complex within the solid’s pores by the reaction of the organic ligand with the metal cation previously introduced in the support. The direct deposition of the organometallic complex in the support resulted in an active catalyst which gives polyethylene with the same microstructure as the one obtained with the related homogeneous systems. The heterogeneous catalysts obtained by reaction of the ligand with the metal already present in the support showed a lower catalytic activity.

A facile approach to fabricate halloysite/metal nanocomposites with preformed and in situ synthesized metal nanoparticles: a comparative study of their enhanced catalytic activity

2015 ◽  
Vol 44 (19) ◽  
pp. 8906-8916 ◽  
Author(s):  
Sankar Das ◽  
Subhra Jana
Keyword(s):  
Catalytic Activity ◽  
Comparative Study ◽  
Metal Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Cost Effective ◽  
Environmentally Benign ◽  
Metal Nanocomposites

Halloysite/metal nanocomposites have been synthesized through the immobilization of preformed and in situ synthesized metal nanoparticles over halloysite surfaces, which in turn produce efficient, cost-effective, and environmentally benign heterogeneous catalysts.

Pd/meso-CoO derived from in situ reduction of the one-step synthesized Pd/meso-Co3O4: high-performance catalysts for benzene combustion

2019 ◽  
Vol 43 (31) ◽  
pp. 12358-12368 ◽  
Author(s):  
Xingtian Zhao ◽  
Ran Zhang ◽  
Yuxi Liu ◽  
Jiguang Deng ◽  
Peng Xu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Performance ◽  
Oxygen Activation ◽  
In Situ Reduction ◽  
Templating Method ◽  
One Step ◽  
The One

The 0.93Pd/meso-CoO is prepared via in situ reduction of 0.85Pd/meso-Co3O4 derived from KIT-6-templating method. The excellent catalytic activity of 0.93Pd/meso-CoO is related to the formed Pd0 species and good oxygen activation ability.

In situ spectroscopic studies of the one-pot synthesis of composition-controlled Cu–Ni nanowires with enhanced catalytic activity

2018 ◽  
Vol 42 (15) ◽  
pp. 13044-13053 ◽  
Author(s):  
Masanao Ishijima ◽  
Jhon L. Cuya Huaman ◽  
Shun Yokoyama ◽  
Kozo Shinoda ◽  
Masahito Uchikoshi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Formation Mechanism ◽  
Spectroscopic Studies ◽  
Reduction Technique ◽  
One Pot ◽  
Spectroscopic Measurements ◽  
One Pot Synthesis ◽  
The One ◽  
Alcohol Reduction

Development of a novel alcohol reduction technique for the one-pot synthesis of Cu–Ni NWs by elucidating the formation mechanism by using in situ spectroscopic measurements.

scholarly journals Study the Effect of Various Sulfonation Methods on Catalytic Activity of Carbohydrate-Derived Catalysts for Ester Production

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 638
Author(s):  
Nur Hidayah Deris ◽  
Umer Rashid ◽  
Soroush Soltani ◽  
Thomas Shean Yaw Choong ◽  
Imededdine Arbi Nehdi
Keyword(s):  
Catalytic Activity ◽  
Fatty Acid ◽  
Thermal Treatment ◽  
Heterogeneous Catalysts ◽  
In Situ Polymerization ◽  
Acid Methyl Ester ◽  
Ft Ir ◽  
Concentrated Sulfuric Acid ◽  
Temperature Programmed

In the present study, four types of sulfonation method, including thermal treatment with concentrated sulfuric acid (H2SO4), thermal decomposition of ammonium sulphate (NHSO4), thermal treatment with chlorosulfonic in chloroform (HSO3Cl), and in situ polymerization of poly(sodium4-styrenesulfonate) (PSS), were employed to convert incomplete carbonized glucose (ICG) to sulfonated heterogeneous catalysts for the fatty acid methyl ester (FAME) production. The characteristics of synthesized catalysts were further examined using Raman spectroscopy, Fourier transformation infrared (FT-IR), ammonia temperature programmed desorption (NH3-TPD), Brunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX). According to experiments, the sulfonic acid density was varied in a range from 4.408 to 14.643 mmol g−1 over various sulfonation methods. The catalytic activity of synthesized catalysts over different sulfonation methods was determined by performing the conversion of palm fatty acid distillate (PFAD) to ester synthesis in a batch-system reactor. The findings reveal that using PSS-ICG resulted in the highest FAME yield of 96.3% followed by HSO3Cl-ICG of 94.8%, NHSO4-ICG of 84.2%; and H2SO4-ICG of 77.2%. According to results, the ICG sulfonated by PSS method with the highest acid density (14.643 mmol g−1) gave the highest catalytic activity over PFAD conversion to biodiesel. According to experiment results, acid density played a crucial role over FAME yield percentage. Besides acid density, it is also worth mentioning that various sulfonation methods including different mechanisms, chemicals and sulfonating agents played crucial roles in the FAME yield percentage.

Catalytic activity of rhodium(I) complexes containing (ω-trimethylsilylalkyl)diphenylphosphines

1980 ◽  
Vol 45 (8) ◽  
pp. 2219-2223 ◽  
Author(s):  
Marie Jakoubková ◽  
Martin Čapka
Keyword(s):  
Catalytic Activity ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Electron Density ◽  
Phosphorus Atom ◽  
Proton Acceptor ◽  
Trimethylsilyl Group ◽  
Kinetics Of

Kinetics of homogenous hydrogenation of 1-heptene catalysed by rhodium(I) complexes prepared in situ from μ,μ'-dichloro-bis(cyclooctenerhodium) and phosphines of the type RP(C6H5)2 (R = -CH3, -(CH2)nSi(CH3)3; n = 1-4) have been studied. The substitution of the ligands by the trimethylsilyl group was found to increase significantly the catalytic activity of the complexes. The results are discussed in relation to the electron density on the phosphorus atom determined by 31P NMR spectroscopy and to its proton acceptor ability determined by IR spectroscopy.

scholarly journals NIR responsive tumor vaccine in situ for photothermal ablation and chemotherapy to trigger robust antitumor immune responses

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Lirong Zhang ◽  
Jingjing Zhang ◽  
Lixia Xu ◽  
Zijian Zhuang ◽  
Jingjin Liu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Tumor Vaccine ◽  
Oxidative Polymerization ◽  
Delivery Mode ◽  
Tumor Treatment ◽  
One Pot ◽  
Photothermal Ablation ◽  
Prolonged Retention ◽  
The One

Abstract Background Therapeutic tumor vaccine (TTV) that induces tumor-specific immunity has enormous potentials in tumor treatment, but high heterogeneity and poor immunogenicity of tumor seriously impair its clinical efficacy. Herein, a novel NIR responsive tumor vaccine in situ (HA-PDA@IQ/DOX HG) was prepared by integrating hyaluronic acid functionalized polydopamine nanoparticles (HA-PDA NPs) with immune adjuvants (Imiquimod, IQ) and doxorubicin (DOX) into thermal-sensitive hydrogel. Results HA-PDA@IQ NPs with high photothermal conversion efficiency (41.2%) and T1-relaxation efficiency were using HA as stabilizer by the one-pot oxidative polymerization. Then, HA-PDA@IQ loaded DOX via π-π stacking and mixed with thermal-sensitive hydrogel to form the HA-PDA@IQ/DOX HG. The hydrogel-confined delivery mode endowed HA-PDA@IQ/DOX NPs with multiple photothermal ablation performance once injection upon NIR irradiation due to the prolonged retention in tumor site. More importantly, this mode enabled HA-PDA@IQ/DOX NPs to promote the DC maturation, memory T cells in lymphatic node as well as cytotoxic T lymphocytes in spleen. Conclusion Taken together, the HA-PDA@IQ/DOX HG could be served as a theranostic tumor vaccine for complete photothermal ablation to trigger robust antitumor immune responses.

scholarly journals Morphology Controlled Synthesis of γ-Al2O3 Nano-Crystallites in Al@Al2O3 Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 310
Author(s):  
Dohyeon Han ◽  
Doohwan Lee
Keyword(s):  
Electrostatic Interactions ◽  
Heterogeneous Catalysts ◽  
Metal Substrate ◽  
Inorganic Anions ◽  
Core Shell ◽  
Hydroxyl Groups ◽  
Hydrothermal Reactions ◽  
Fine Control ◽  
Reaction Processes

Fine control of morphology and exposed crystal facets of porous γ-Al2O3 is of significant importance in many application areas such as functional nanomaterials and heterogeneous catalysts. Herein, a morphology controlled in situ synthesis of Al@Al2O3 core–shell architecture consisting of an Al metal core and a porous γ-Al2O3 shell is explored based on interfacial hydrothermal reactions of an Al metal substrate in aqueous solutions of inorganic anions. It was found that the morphology and structure of boehmite (γ-AlOOH) nano-crystallites grown at the Al-metal/solution interface exhibit significant dependence on temperature, type of inorganic anions (Cl−, NO3−, and SO42−), and acid–base environment of the synthesis solution. Different extents of the electrostatic interactions between the protonated hydroxyl groups on (010) and (001) facets of γ-AlOOH and the inorganic anions (Cl−, NO3−, SO42−) appear to result in the preferential growth of γ-AlOOH toward specific crystallographic directions due to the selective capping of the facets by adsorption of the anions. It is hypothesized that the unique Al@Al2O3 core–shell architecture with controlled morphology and exposed crystal-facets of the γ-Al2O3 shell can provide significant intrinsic catalytic properties with enhanced heat and mass transport to heterogeneous catalysts for applications in many thermochemical reaction processes. The direct fabrication of γ-Al2O3 nano-crystallites from Al metal substrate with in-situ modulation of their morphologies and structures into 1D, 2D, and 3D nano-architectures explored in this work is unique and can offer significant opportunities over the conventional methods.

In situ construction of phenanthroline-based cationic radical porous hybrid polymers for metal-free heterogeneous catalysis

2021 ◽  
Vol 9 (12) ◽  
pp. 7556-7565
Author(s):  
Guojian Chen ◽  
Yadong Zhang ◽  
Ke Liu ◽  
Xiaoqing Liu ◽  
Lei Wu ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Hybrid Polymers ◽  
Metal Free ◽  
Oxidation Of Sulfides

Constructing phenanthroline-based cationic radical porous hybrid polymers as versatile metal-free heterogeneous catalysts for both oxidation of sulfides and CO2 conversion.

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