scholarly journals THE RÔLE OF CERTAIN METALLIC IONS AS OXIDATION CATALYSTS

1926 ◽  
Vol 10 (2) ◽  
pp. 289-312 ◽  
Author(s):  
S. F. Cook
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Empirical Equation ◽  
Initial Rate ◽  
Fractional Power ◽  
Logarithmic Function ◽  
Metallic Ions ◽  
Colloidal State ◽  
Colloidal Metal ◽  
Cadmium Zinc

1. When iron and copper are allowed to act on hydrogen peroxide and pyrogallol, enough carbon dioxide is produced to be readily measured. 2. The curve of the production of carbon dioxide may be fitted by an empirical equation, by the use of which the initial rate and the total amount of the oxidation may be determined. 3. The effect of the concentration of the reagents is different in each case, the effect varying as a fractional power of the copper and pyrogallol concentrations and as a logarithmic function of the hydrogen peroxide concentration. 4. When gold or silver is used the rate changes suddenly during the course of the reaction due to the precipitation of colloidal metal. 5. Mercury, cadmium, zinc, tin, and some other metals have no effect. 6. A theoretical set of equations is assumed to account for the action of the metals. 7. The metals are assumed to act by means of the formation of intermediate peroxides. 8. Experiments on the action of gold indicate that the metals are active in the ionic and not in the colloidal state.

scholarly journals Crystallization and preliminary X-ray analysis of formate oxidase, an enzyme of the glucose–methanol–choline oxidoreductase family

2010 ◽  
Vol 66 (9) ◽  
pp. 1064-1066 ◽  
Author(s):  
Yoshifumi Maeda ◽  
Daiju Doubayashi ◽  
Takumi Ootake ◽  
Masaya Oki ◽  
Bunzo Mikami ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Single Crystal ◽  
Aspergillus Oryzae ◽  
Diffraction Data ◽  
Diffusion Method ◽  
Hanging Drop ◽  
Space Group ◽  
X Ray ◽  
Vapour Diffusion

Formate oxidase (FOD), which catalyzes the oxidation of formate to yield carbon dioxide and hydrogen peroxide, belongs to the glucose–methanol–choline oxidoreductase (GMCO) family. FOD fromAspergillus oryzaeRIB40, which has a modified FAD as a cofactor, was crystallized at 293 K by the hanging-drop vapour-diffusion method. The crystal was orthorhombic and belonged to space groupC2221. Diffraction data were collected from a single crystal to 2.4 Å resolution.

Influence of Compressed Carbon Dioxide on the Oxidation of Cyclohexane with Hydrogen Peroxide in Acetic Acid

2006 ◽  
Vol 59 (3) ◽  
pp. 225 ◽  
Author(s):  
Liang Gao ◽  
Tao Jiang ◽  
Buxing Han ◽  
Baoning Zong ◽  
Xiaoxin Zhang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Binary System ◽  
Reaction System ◽  
Phase Region ◽  
Phase Behaviour ◽  
Phase System ◽  
Two Phase ◽  
Three Phase

The oxidation of cyclohexane with H2O2 in a compressed CO2/acetic acid binary system was studied at 60.0 and 80.0°C, at pressures up to 18 MPa, and with the zeolite TS-1 as catalyst. The phase behaviour of the reaction system was also observed. There are three fluid phases in the reaction system at lower pressure but two at higher pressures. In the three-phase region the yields of the products, cyclohexanol and cyclohexanone, increase considerably with increasing pressure and reaches a maximum near the phase-separating pressure. CO2 can thus enhance the reaction effectively. However, the effect of pressure on the yield is very limited after the transition to a two-phase system.

scholarly journals The mechanism of carbon assimilation in green plants: the photolytic decomposition of carbon dioxide in vitro

1906 ◽  
Vol 78 (526) ◽  
pp. 318-327 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Carbon Assimilation ◽  
Enzymic Activity ◽  
Green Plants ◽  
Negative Results ◽  
Positive Side ◽  
Uranium Compounds ◽  
Photolytic Decomposition

In a previous paper* it was shown that carbon dioxide is decomposed in the green parts of plants independently of vital or enzymic activity, formaldehyde and hydrogen peroxide being produced. It follows from the analysis of the process of carbon assimilation there set out that this first step, the photolysis of carbon dioxide, should be capable of being artificially induced under laboratory conditions. It is impossible here to give a brief account of the work of previous investigators on these lines; it is sufficient to state that all experiments with chlorophyll solutions have given negative results, and as regards those with other forms of chlorophyll, such as dried powdered leaves or expressed juice, the balance of evidence favours the view that to decomposition takes place. Reference may be made to papers by Friedel and Macchiati on the positive side, and by Harroy,§ Herzog,|| and, quite recently, Bernard,¶ who obtained only negative results. Experiments with uranium compounds will be considered later.

scholarly journals Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Philippe Boduch ◽  
Enio Frota da Silveira ◽  
Alicja Domaracka ◽  
Oscar Gomis ◽  
Xue Yang Lv ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Solar System ◽  
Ion Irradiation ◽  
Pure Water ◽  
Outer Solar System ◽  
Water Ice ◽  
Icy Moons ◽  
Different Temperatures ◽  
Frozen Gases

Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc.) of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone) after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.

scholarly journals Formaldehyde as an oxidation product of chlorophyll extracts

1914 ◽  
Vol 87 (596) ◽  
pp. 378-385 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Alcoholic Solution ◽  
Light Petroleum ◽  
Not Given ◽  
Moist Air ◽  
Reduced Pressure ◽  
Synthetic Process ◽  
Chlorophyll Extracts

Of recent years the action on carbon dioxide of chlorophyll in vitro has assumed some importance as possibly throwing light on the nature of the photo-synthetic process of green plants. Thus Usher and Priestley have stated that films of extracted chlorophyll in the presence of moist air and carbon dioxide produce formaldehyde and hydrogen peroxide under the influence of light. The earlier work of these authors has been adversely commented upon by several writers, notably by Ewart, to whose criticisms Usher and Priestley have replied with a number of additional experiments and arguments, referring also to the work of Schryver, subsequent to that of Ewart, as affording strong confirmation of their views as far as the synthesis of the aldehyde is concerned. The facts set forth in the present paper came to light during an attempt to confirm and extend the observations of Usher and Priestley and of Schryver. Grass was extracted with alcohol, usually in the cold and in the presence of calcium carbonate. In some experiments the alcoholic liquid was evaporated to dryness under reduced pressure and the residue extracted with ether; in others a solution of chlorophyll in light petroleum was obtained by shaking the alcoholic solution with that liquid. The method of experiment was based upon that described by Schryver, the ether or petroleum extract being allowed to evaporate on glass plates and exposed to light under the various conditions to be mentioned below. As was the case in the later experiments of Usher and Priestley themselves, the test which has been relied upon for the detection of formaldehyde is the very delicate one devised by Schryver, who has found that the reaction is not given by such other members of the series as have been examined up to the present. It has been assumed in the course of these experiments, as in the work of the investigators already mentioned, that the aldehyde produced is formaldehyde, but it is very important that the possibility of the observed effects being due to some other aldehyde or to a mixture of aldehydes should be borne in mind. This point still requires investigation.

The oxidation of gaseous glyoxal

1965 ◽  
Vol 288 (1412) ◽  
pp. 1-16 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Carbon Monoxide ◽  
Oxalic Acid ◽  
The Other ◽  
Product Analysis ◽  
Glyoxalic Acid ◽  
Induced Decomposition ◽  
Two Stages

The oxidation of gaseous glyoxal has been studied at temperatures between 290 and 370 °C both manometrically and by detailed product analysis. The reaction has been shown to occur in two stages; in the first, glyoxal reacts to give mainly carbon monoxide and glyoxalic acid and in the second, glyoxalic acid is subject to further oxidation to oxalic acid, hydrogen peroxide, carbon dioxide and water. Of the two previous investigations of the reaction, that of Steacie, Hatcher & Horwood (1935 a ) has been shown to have been concerned with the first stage and in the other (Newitt, Baxt & Kelkar 1939), carried out at ignition temperatures, the reaction proceeded through both stages. The oxidation is accompanied by an oxygen induced decomposition and a mechanism similar to that proposed by one of us (Axford & Norrish 1948) for the oxidation of formaldehyde, involving OH, CHO and HO 2 radicals has been developed and shown to account satisfactorily for the observed facts.

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