scholarly journals Greener and Sustainable Approach for the Synthesis of Commercially Important Epoxide Building Blocks Using Polymer-Supported Mo(VI) Complexes as Catalysts

2017 ◽  
pp. 65-97
Author(s):  
Misbahu Ladan Mohammed ◽  
Basudeb Saha
Keyword(s):  
Building Blocks ◽  
Commercially Important ◽  
Polymer Supported

scholarly journals Polymer-supported synthesis of N-substituted anthranilates as the building blocks for preparation of N-arylated 3-hydroxyquinolin-4(1H)-ones

RSC Advances ◽  
2021 ◽  
Vol 11 (16) ◽  
pp. 9362-9365
Author(s):  
Soňa Krajčovičová ◽  
Jan Hlaváč ◽  
Kristýna Vychodilová
Keyword(s):  
Building Blocks ◽  
Substituted Anilines ◽  
Polymer Supported

Fast and simple access to N-arylated 3-hydroxyquinolin-4(1H)-ones starting from easily available 1-methyl-2-iodoterephthalate and variously substituted anilines is presented.

Photochemical Evolution of Interstellar/Precometary Organic Material

1997 ◽  
Vol 161 ◽  
pp. 23-47 ◽  
Author(s):  
Louis J. Allamandola ◽  
Max P. Bernstein ◽  
Scott A. Sandford
Keyword(s):  
Origin Of Life ◽  
Building Blocks ◽  
Complex Species ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Polycyclic Aromatic ◽  
Ultraviolet Photolysis ◽  
The Origin Of Life ◽  
Simple Molecules ◽  
Complex Organic

AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.

Cathodoluminescence of Catalyst Crystallites

1982 ◽  
Vol 40 ◽  
pp. 664-665
Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick
Keyword(s):  
Defect Density ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Semiconductor Materials ◽  
Environmental Cell ◽  
High Resolution Structure ◽  
Commercially Important ◽  
Crystallographic Defects ◽  
Resolution Structure

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Peroxisome proliferation: Organelles or activity as an endpoint?

1993 ◽  
Vol 51 ◽  
pp. 396-397
Author(s):  
Catherine A. Taylor ◽  
Bruce M. Jarnot
Keyword(s):  
Acid Oxidation ◽  
Peroxisome Proliferation ◽  
Post Dose ◽  
Oxidation Activity ◽  
Wasting Syndrome ◽  
Perfluorodecanoic Acid ◽  
Hypolipidemic Agent ◽  
Commercially Important ◽  
Acyl Coa Oxidase ◽  
Mitochondrial Disruption

Peroxisome induction can be expressed as an increase in peroxisome area (proliferation) or as an increase in peroxisomal fatty acid oxidation (activity). This study compares proliferation and activity as endpoints for hepatic peroxisome induction by perfluorodecanoic acid (PFDA). Fluorocarboxylic acids such as PFDA represent a class of compounds possessing commercially important surfactant properties. A single 50 mg/Kg ip. dose of PFDA produces a characteristic “wasting syndrome” in male F-344 rats. Symptoms include hypophagia, weight loss, hepatomegaly, and delayed lethality. Hepatic studies reveal changes similar to those seen with the hypolipidemic agent clofibrate. These include mitochondrial disruption, endoplasmic reticulum and peroxisome proliferation, and increased peroxisomal acyl-CoA oxidase activity.Male Fisher-344 rats received a single ip. dose of 2, 20, or 50mg/Kg PFDA dissolved in 1:1 propylene glycol/water and were sacrificed 8 days post-dose. All control rats received an equal volume of vehicle ip. Animals were provided food and water ad libitum, except pair-fed controls which received the same restrictive food intake consumed by their weight-paired dosed partners (50mg/Kg PFDA group) to simulate the hypophagia associated with PFDA.

Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions

1993 ◽  
Vol 51 ◽  
pp. 876-877
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Microstructural Characterization ◽  
Building Blocks ◽  
Quantitative Information ◽  
Physical Models ◽  
Specimen Preparation ◽  
Time Resolved ◽  
Temperature Changes ◽  
Temperature And Humidity ◽  
Microstructured Fluids ◽  
Air Streams

To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

Sign in / Sign up

Export Citation Format

Share Document