1,2,3-Trimethoxypropane, a glycerol-based solvent with low toxicity: new utilization for the reduction of nitrile, nitro, ester, and acid functional groups with TMDS and a metal catalyst

2013 ◽  
Vol 15 (11) ◽  
pp. 3020 ◽  
Author(s):  
Marc Sutter ◽  
Leyla Pehlivan ◽  
Romain Lafon ◽  
Wissam Dayoub ◽  
Yann Raoul ◽  
...  
Keyword(s):  
Functional Groups ◽  
Metal Catalyst ◽  
Low Toxicity

scholarly journals Applications of Modified Biochar-Based Materials for the Removal of Environment Pollutants: A Mini Review

2020 ◽  
Vol 12 (15) ◽  
pp. 6112 ◽  
Author(s):  
Jung Eun Lee ◽  
Young-Kwon Park
Keyword(s):  
Iron Oxides ◽  
Functional Groups ◽  
Advanced Oxidation Process ◽  
Catalyst Support ◽  
Environmental Pollutants ◽  
Metal Catalyst ◽  
Modified Biochar ◽  
Eutrophic Water ◽  
Iron Iron ◽  
Titanium Dioxides

The biochar treated through several processes can be modified and utilized as catalyst or catalyst support due to specific properties with various available functional groups on the surface. The functional groups attached to the biochar surface can initiate active radical species to play an important role, which lead to the destruction of contaminants as a catalyst and the removal of adsorbent by involving electron transfer or redox processes. Centering on the high potential to be developed in field applications, this paper reviews more feasible and sustainable biochar-based materials resulting in efficient removals of environmental pollutants as catalyst or support rather than describing them according to the technology category. This review addresses biochar-based materials for utilization as catalysts, metal catalyst supports of iron/iron oxides, and titanium dioxide because the advanced oxidation process using iron/iron oxides or titanium dioxides is more effective for the removal of contaminants. Biochar-based materials can be used for the removal of inorganic contaminants such as heavy meals and nitrate or phosphate to cause eutrophication of water. The biochar-based materials available for the remediation of eutrophic water by the release of N- or P-containing compounds is also reviewed.

Hypervalent Iodine-mediated/Catalyzed Oxidative Cycloisomerization/Annulation of Alkynes for Metal-free Synthesis of Oxazoles

2020 ◽  
Vol 24 (18) ◽  
pp. 2048-2069
Author(s):  
Akio Saito
Keyword(s):  
Functional Groups ◽  
Single Step ◽  
Biologically Active ◽  
Hypervalent Iodine ◽  
Sustainable Chemistry ◽  
Metal Free ◽  
Triple Bonds ◽  
Iodine Species ◽  
Low Toxicity ◽  
Synthetic Intermediates

Since oxazoles have found widespread applications not only as synthetic intermediates but also as biologically active compounds, much effort has been focused on developing novel and efficient methods for the synthesis of this heterocycle. From the viewpoint of green and sustainable chemistry, hypervalent iodine and other halogen reagents have gained increasing popularity in metal-free oxidative transformation due to their low toxicity, transition-metal-like reactivity, high stability, easy handling and other benefits. In this account, our two approaches to the metal-free synthesis of oxazoles by means of a peculiar activation of alkynes by iodine species are described with the related contexts. One is iodine(III)-mediated/catalyzed oxidative cycloisomerization reactions of N-propargyl amides for the preparation of oxazoles bearing various functional groups at their side chains. In these reactions, iodine(III) species works as a donor of various heteroatomic functional groups as well as an activator of carbon-carbon triple bonds in a single step. Furthermore, this methodology can be extended to iodine(III)-mediated/catalyzed oxidative annulation of alkynes and nitriles as another approach, in which heteroatoms on iodine(III) species are incorporated in the azole rings.

scholarly journals Methylation of Eugenol Using Dimethyl Carbonate and Bentonite as Catalyst

2015 ◽  
Vol 15 (3) ◽  
pp. 256-262 ◽  
Author(s):  
Dina Asnawati ◽  
I Made Sudarma ◽  
Emmy Yuanita ◽  
Baiq Fadila Arlina ◽  
Saprini Hamdiani ◽  
...  
Keyword(s):  
Functional Groups ◽  
Dimethyl Sulphate ◽  
Dimethyl Carbonate ◽  
Methyl Halides ◽  
Light Yellow ◽  
Light Yellow Liquid ◽  
Low Toxicity

Eugenol is a compound with a variety of reactive functional groups such as allyl, hydroxy and methoxy. The presence of the functional groups brings eugenol possible to undertake the transformation into various derivative compounds with diverse activities. One of the simple and possible transformations is methylation or alkylation. Commonly, methyl halides and dimethyl sulphate are used as methylation agent. However, those kinds of methylation agents are toxic and carcinogenic. In this research dimethyl carbonate, an alternative methylation agent is used, because of its low toxicity, green, and economic. The synthesis has been carried out by using a catalyst. Bentonite was activated by heating to a temperature using 300 °C. Methylation was shown by the formation of a light yellow liquid (25.71% yield). The structures of products were characterized by GC-MS and obtained a compound, namely bis eugenol (4-allyl-2-methoxyphenoxy) methane (2.37% yield).

scholarly journals Axially Ligated Mesohemins as Bio-Mimicking Catalysts for Atom Transfer Radical Polymerization

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3969 ◽  
Author(s):  
Liye Fu ◽  
Antonina Simakova ◽  
Sangwoo Park ◽  
Yi Wang ◽  
Marco Fantin ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Protein Structures ◽  
Metal Catalyst ◽  
Iron Porphyrin ◽  
Atom Transfer ◽  
Natural Protein ◽  
Naturally Occurring ◽  
Low Toxicity

Copper is the most common metal catalyst used in atom transfer radical polymerization (ATRP), but iron is an excellent alternative due to its natural abundance and low toxicity compared to copper. In this work, two new iron-porphyrin-based catalysts inspired by naturally occurring proteins, such as horseradish peroxidase, hemoglobin, and cytochrome P450, were synthesized and tested for ATRP. Natural protein structures were mimicked by attaching imidazole or thioether groups to the porphyrin, leading to increased rates of polymerization, as well as providing polymers with low dispersity, even in the presence of ppm amounts of catalysts.

scholarly journals Metal-Bound or Free Ylides as Reaction Intermediates in Metal-Catalyzed [2,3]-Sigmatropic Rearrangements? It Depends.

2020 ◽  
Author(s):  
Croix Laconsay ◽  
Dean Tantillo
Keyword(s):  
Density Functional Theory ◽  
Case Studies ◽  
Functional Groups ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Metal Catalyst ◽  
Reaction Intermediates ◽  
Functional Theory ◽  
Sigmatropic Rearrangements ◽  
Metal Catalyzed

<p>Density functional theory calculations were applied to study four previously published metal-catalyzed [2,3]-rearrangements from onium ylide intermediates, in pursuit of generalizations about when, during these types of reactions, catalysts dissociate. Our results corroborate past studies where free ylide mechanisms were proposed to be operative. Calculations on case studies predict that the origin of metal-catalyst ‘falling off’ (dissociation) can be attributed primarily to the steric bulkiness of functional groups adjacent to the carbene carbon. </p>

scholarly journals Metal-Bound or Free Ylides as Reaction Intermediates in Metal-Catalyzed [2,3]-Sigmatropic Rearrangements? It Depends.

2020 ◽  
Author(s):  
Croix Laconsay ◽  
Dean Tantillo
Keyword(s):  
Density Functional Theory ◽  
Case Studies ◽  
Functional Groups ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Metal Catalyst ◽  
Reaction Intermediates ◽  
Functional Theory ◽  
Sigmatropic Rearrangements ◽  
Metal Catalyzed

<p>Density functional theory calculations were applied to study four previously published metal-catalyzed [2,3]-rearrangements from onium ylide intermediates, in pursuit of generalizations about when, during these types of reactions, catalysts dissociate. Our results corroborate past studies where free ylide mechanisms were proposed to be operative. Calculations on case studies predict that the origin of metal-catalyst ‘falling off’ (dissociation) can be attributed primarily to the steric bulkiness of functional groups adjacent to the carbene carbon. </p>

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

Elemental Distribution in Pt-Re:Al2O3 Naphtha Reforming Catalysts

1980 ◽  
Vol 38 ◽  
pp. 200-201
Author(s):  
R. L. Freed ◽  
M. J. Kelley
Keyword(s):  
Bimetallic Catalyst ◽  
Supported Catalysts ◽  
Coke Formation ◽  
Materials Characterization ◽  
Metal Catalyst ◽  
Elemental Distribution ◽  
Exact Nature ◽  
Naphtha Reforming ◽  
Reforming Catalysts ◽  
Commercial Introduction

The commercial introduction of Pt-Re supported catalysts to replace Pt alone on Al2O3 has brought improvements to naphtha reforming. The bimetallic catalyst can be operated continuously under conditions which lead to deactivation of the single metal catalyst by coke formation. Much disagreement still exists as to the exact nature of the bimetallic catalyst at a microscopic level and how it functions in the process so successfully. The overall purpose of this study was to develop the materials characterization tools necessary to study supported catalysts. Specifically with the Pt-Re:Al2O3 catalyst, we sought to elucidate the elemental distribution on the catalyst.

Improving integration between functional groups: A case in organization change and implications for theory and practice

1971 ◽  
Author(s):  
Warren G. Bennis ◽  
Michael Beer ◽  
Gerald R. Pieters ◽  
Alan T. Hundert ◽  
Samuel H. Marcus ◽  
...  
Keyword(s):  
Functional Groups ◽  
Organization Change ◽  
Theory And Practice
Sign in / Sign up

Export Citation Format

Share Document