On the formation of the carbon dioxide anion radical CO2− · in the gas phase

1999 ◽  
Vol 185-187 ◽  
pp. 25-35 ◽  
Author(s):  
Detlef Schröder ◽  
Christoph A Schalley ◽  
Jeremy N Harvey ◽  
Helmut Schwarz
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
Anion Radical

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

Gas phase interaction with catalytic oxidation reactions

1972 ◽  
Vol 326 (1565) ◽  
pp. 215-227 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Maleic Anhydride ◽  
Catalytic Oxidation ◽  
Gas Phase ◽  
Major Part ◽  
Oxidation Reactions ◽  
Mixed Gas ◽  
Kinetics Of ◽  
Oxidation Of Benzene ◽  
Homogeneous Decomposition

Studies of the catalytic oxidation of benzene to maleic anhydride and carbon dioxide over vanadia/molybdena catalysts show that the major part of the reaction involves interacting gas and gas-solid processes. The results are consistent with a mechanism in which a benzeneoxygen adduct is formed catalytically, desorbs and then reacts to give maleic anhydride entirely in the gas phase. On the basis of this proposed mechanism, the kinetics of individual reactions have been investigated in some depth. The over-oxidation of maleic anhydride has been found to be not significant under the conditions of reaction. The kinetic relationships governing the homogeneous decomposition of the adduct and the oxidation of the adduct to maleic anhydride and to carbon dioxide have been established. The results show that essentially all of the anhydride originates from mixed gas-solid/gas reaction while substantial amounts of carbon dioxide are produced entirely catalytically.

scholarly journals Effect of extraction conditions of paprika oleoresins on their free radical scavenging and anticancer activity

2014 ◽  
Vol 12 (3) ◽  
pp. 377-385 ◽  
Author(s):  
Vesna Šaponjac ◽  
Dragana Četojević-Simin ◽  
Gordana Ćetković ◽  
Jasna Čanadanović-Brunet ◽  
Sonja Djilas ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Cell Line ◽  
Antiproliferative Activity ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Radical Scavenging ◽  
Superoxide Anion Radical ◽  
Food Ingredients ◽  
Supercritical Carbon

AbstractGround spice paprika was extracted with hexane, by conventional Soxhlet procedure (SX oleoresin), and with supercritical carbon dioxide at three different pressures — 20, 30 and 40 MPa (SF20, SF30 and SF40 oleoresins). The effect of extraction method and conditions on the colour intesity of paprika oleoresins, content of α-tocopherol, as well as antioxidant and antiproliferative activity was examined. Hexane showed highest selectivity for paprika pigments (886.02 ASTA), while α-tocopherol showed highest solubility (3846.9 mg kg−1) in supercritical carbon dioxide at 20 MPa. All paprika oleoresins exhibited good superoxide anion radical scavenging activity SF30 being the best superoxide anion radical scavenger. Cell growth activity was evaluated in vitro in human cell lines:cervix epitheloid carcinoma (HeLa), breast adenocarcinoma (MCF7) and colon adenocarcinoma (HT-29). The highest antiproliferative activity was exhibited by SX in MCF7 cell line (IC50=14.28 mg mL−1). Extract SF40 produced significant and selective antiproliferative action towards HeLa cell line. These results suggest that paprika oleoresins, due to high antiradical and tumor cell-inhibiting activity, can be regarded as functional food ingredients.

Active site separation of photocatalytic steam reforming of methane using Gas‐Phase Photoelectrochemical system

2021 ◽  
Author(s):  
Tomoki Kujirai ◽  
Akira Yamaguchi ◽  
Takeshi Fujita ◽  
Hideki Abe ◽  
Masahiro Miyauchi
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
High Temperatures ◽  
Steam Reforming ◽  
Active Site ◽  
Side Reaction ◽  
System P ◽  
Steam Reforming Of Methane

Steam reforming of methane (SRM) requires high temperatures to be promoted, and the production of carbon dioxide from the side reaction has also become a problem. In this study, we...

Rapid-responding carbon dioxide and oxygen electrodes

1964 ◽  
Vol 19 (3) ◽  
pp. 550-553 ◽  
Author(s):  
Irving Fatt
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
Filter Paper ◽  
Oxygen Electrode ◽  
Membrane Material ◽  
Millipore Filter ◽  
Oxygen Electrodes ◽  
Final Response ◽  
Pco2 Measurement ◽  
Po2 Measurement

Redesign of the Severinghaus pCO2 and the Clark pO2 electrodes yields electrodes which are easier to make and assemble. When used with a new membrane material, paraffin-treated Millipore filter paper, the redesigned Severinghaus pCO2 electrode gives 99% response in 15 sec for a 40 mm Hg change in pCO2 in the region of 15–60 mm Hg pCO2 in either gas or water phase. The redesigned Clark pO2 electrode when used with treated Millipore paper gives 99% of final response in 1.24 sec for a 155 mm Hg change of pO2 in the gas phase in the range 0–160 mm Hg pO2. In aqueous solutions this electrode gives 99% response in 30 sec. Severinghaus electrode; polarographic oxygen electrode; pCO2 measurement; pO2 measurement Submitted on March 19, 1963

Gas-phase ion-molecule reactions of dioxygen anion radical (O2-.bul.)

1985 ◽  
Vol 107 (14) ◽  
pp. 4123-4128 ◽  
Author(s):  
Richard N. McDonald ◽  
A. Kasem Chowdhury
Keyword(s):  
Gas Phase ◽  
Anion Radical ◽  
Ion Molecule Reactions ◽  
Gas Phase Ion

scholarly journals Gas phase synthesis of dimethyl carbonate from CO2 and CH3OH over Cu-Ni/AC. A kinetic study

2019 ◽  
pp. 88-99 ◽  
Author(s):  
Oscar Felipe Arbeláez-Pérez ◽  
Sara Dominguez Cardozo ◽  
Andrés Felipe Orrego-Romero ◽  
Aida Luz Villa Holguin ◽  
Felipe Bustamante Londoño
Keyword(s):  
Carbon Dioxide ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Gas Phase ◽  
Dimethyl Carbonate ◽  
Direct Synthesis ◽  
Dispersion Analysis ◽  
Molar Ratio ◽  
Rate Determining Step ◽  
Carbonate Formation

The catalytic activity for dimethyl carbonate formation from carbon dioxide and methanol over mono and bimetallic Cu:Ni supported on activated carbon is presented. Bimetallic catalysts exhibit higher catalytic activity than the monometallic samples, being Cu:Ni-2:1 (molar ratio) the best catalyst; X-Ray diffraction, transmission electron microscopy, and metal dispersion analysis provided insight into the improved activity. In situ FT-IR experiments were conducted to investigate the mechanism of formation of dimethyl carbonate from methanol and carbon dioxide over Cu-Ni:2-1. The kinetics of the direct synthesis of dimethyl carbonate in gas phase over Cu:Ni-2:1 supported on activated carbon catalyst was experimentally investigated at 12 bar and temperatures between 90 oC and 130 oC, varying the partial pressures of CO2 and methanol. Experimental kinetic data were consistent with a Langmuir–Hinshelwood model that included carbon dioxide and methanol adsorption on catalyst actives sites (Cu, Ni and Cu-Ni), and the reaction of adsorbed CO2 with methoxi species as the rate determining step. The estimated apparent activation energy was 94.2 kJ mol-1.

scholarly journals Calculated Molecular Structures Of Anion Ubiquinone In The Gas Phase, In Solvents And In The Qa Binding Site Of Purple Bacteria Reaction Centers

2012 ◽  
Vol 3 ◽  
pp. 18-23
Author(s):  
Hari Prasad Lamichhane
Keyword(s):  
Binding Site ◽  
Gas Phase ◽  
Anion Radical ◽  
Purple Bacteria ◽  
Polarizable Continuum Model ◽  
Reaction Centers ◽  
Molecular Structures ◽  
Carbonyl Groups ◽  
Methoxy Groups ◽  
Polarizable Continuum

Structural properties of ubiquinone one anion radical (UQ1-) are studied in the gas phase and in QA binding site of purple bacteria reaction center using Gaussian 03. Polarizable continuum model (PCM) and Our own N-layered quantum mechanics + molecular mechanics (ONIOM) methods have been used to optimize the UQ1- molecule in solvent and in the QA binding site of purple bacteria Rhodobactor sphaeroides reaction centers. The UQ1- molecule exist four equivalent conformations of methoxy groups in the gas phase and solvents. However, all four conformations reduce to one in the QA binding site of the purple bacteria reaction centers. Both carbonyl (C=O) bond lengths are similar in all four conformations in the gas phase and in solvents. However, C4=O bond is slightly longer than C1=O bond in the QA binding site. This result infers that QA binding site impacts asymmetric interaction on the carbonyl groups of the quinone molecule.The Himalayan PhysicsVol. 3, No. 32012Page : 18-23

Sign in / Sign up

Export Citation Format

Share Document