The influence of an illuminated mercury surface on the Franck-Cario reactions

1926 ◽  
Vol 23 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Herbert Sim Hirst
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Monoxide ◽  
Catalytic Efficiency ◽  
Mercuric Oxide ◽  
Reaction Products ◽  
Marked Influence ◽  
Mercury Surface ◽  
First Order ◽  
Rate Of Reaction ◽  
Hydrogen Mixtures

It has been found that illumination of a mercury surface by ultraviolet light strong in the line λ=2536·7 Å., exerts a marked influence on the photochemical union of hydrogen andgases such as oxygen, ethylene, and carbon monoxide. The rate of reaction is proportional to the first order to the area of surface exposed.The formation of a mercuric oxide film has been shown to occur only in the presence of a mixture of hydrogen and oxygen, and alternative mechanisms for its formation are suggested.In the case of nitrogen-hydrogen mixtures, hydrazine and ammonia have been identified in the reaction products, and in the case of hydrogen and oxygen, hydrogen peroxide and water have been found, and it is suggested that the reactions proceed in steps.The catalytic efficiency of the surface depends on its cleanness and is cut down by poisons, such as the reaction products in the case of the combination of hydrogen and carbon monoxide.

Methanation on exfoliated and supported MoS2

1989 ◽  
Vol 67 (5) ◽  
pp. 862-866 ◽  
Author(s):  
Guenter A. Scholz ◽  
S. Roy Morrison
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Transition Metal Catalysts ◽  
Surface Species ◽  
Reaction Products ◽  
Third Order ◽  
Ammonium Heptamolybdate ◽  
First Order ◽  
Methanation Reaction ◽  
Improved Performance

The methanation reaction on MoS2 exfoliated to a thickness of a few layers or less and adsorbed onto alumina is found to be very small. However, by calcining and resulfiding the exfoliated MoS2 catalysts, greatly improved performance is achieved that is at least equal to the commercial catalysts based on ammonium heptamolybdate. The creation of molybdenum oxysulflde surface species therefore appears to be a necessary step toward producing significant methanation rates with exfoliated and supported MoS2. The methanation products are almost exclusively CO2 and CH4, their mole ratios near unity, with otherwise only very much smaller amounts of longer chain hydrocarbons. The activation energy for methanation is generally observed to be near 100 kJ/mol, with the overall reaction being first order in the carbon monoxide concentration and third order in the hydrogen concentration. In contrast to the transition-metal catalysts, no water could be detected in the reaction products of the molybdenum based catalyst. Keywords: methanation reaction on MoS2, exfoliated and supported MoS2 as catalyst.

Enzyme catalyzed polymerization and precipitation of aromatic compounds from aqueous solution

1993 ◽  
Vol 20 (5) ◽  
pp. 725-735 ◽  
Author(s):  
J. A. Nicell ◽  
J. K. Bewtra ◽  
N. Biswas ◽  
C. C. St. Pierre ◽  
K. E. Taylor
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Aromatic Compounds ◽  
Thermal Inactivation ◽  
Catalytic Efficiency ◽  
Reaction Products ◽  
Aromatic Substrate ◽  
Aromatic Substrates ◽  
Minimum Residual ◽  
Peroxidase Enzyme

Horseradish peroxidase enzyme (HRP), once activated by hydrogen peroxide, initiates the oxidation of a wide variety of aromatic compounds. Reaction products undergo a non-enzymatic polymerization to form water insoluble aggregates which are readily separated from solution. HRP was selected for application in wastewater treatment systems due to its stability and retention of its catalytic ability over wide ranges of pH and temperature. HRP activity was optimal between pH 5.7 and 8.5 with peak activity occurring at neutral pH. Activity increased with temperature up to 50 °C and declined at higher temperatures due to thermal inactivation. HRP was inactivated rapidly by hydrogen peroxide in the absence of an aromatic substrate. The efficiency of removal that was achieved was dependent on the nature of the aromatic undergoing treatment and the amount of enzyme provided due to the finite lifetime of the catalyst. Optimization of pH significantly improved catalytic efficiency with a corresponding savings in treatment costs. Optimal catalytic lifetime of HRP was achieved in the pH range of 7 to 9 for the eight phenolic compounds treated. The minimum residual level to which aromatic substrates were removed from solution was independent of the starting concentration of the aromatic substrate. Enhanced removal of hard-to-remove compounds was noted when mixtures of aromatic substrates were treated. Key words: horseradish peroxidase enzyme, polymerization, wastewater, phenols, aromatics amines.

Titanocene derivatives of purine and adenine. Synthesis and characterization of reaction products with (η5-C5H5)2Ti(CO)2, (η5-C5H5)2TiCl, and (η5-C5H5)2TiCl2

1986 ◽  
Vol 64 (4) ◽  
pp. 751-759 ◽  
Author(s):  
Daniel Cozak ◽  
Abdelhakim Mardhy ◽  
André Morneau
Keyword(s):  
Carbon Monoxide ◽  
Metal Complex ◽  
Elemental Analysis ◽  
Synthesis And Characterization ◽  
Reaction Products ◽  
First Order ◽  
H Nmr ◽  
New Compounds ◽  
Derivatives Of

The reaction of CpTi(CO)2 (1), Cp2TiCl (2), and Cp2TiCl2 (3) (Cp = η5-C5H5) with purine (PuH) and adenine (AdH) in organic solvents is described. The compound 1 reacts with both molecules in an oxidative fashion giving Cp2Ti(C5H3N4)(C5H4N4) (4) and (Cp2Ti)2(C5H3N5) (5) with concomitant liberation of molecular carbon monoxide and hydrogen (4:1) following a first order rate law in metal complex. The compound 2 forms an adduct compound Cp2TiCl(C5H4N4) (6) with PuH. Monosubstituted derivatives Cp2TiCl(C5H3N4) (7) and Cp2TiCl(C5H4N5) (8) are formed from the reaction of the deprotonated bases with 3. In addition to the usual elemental analysis, the characteristic ir, 1H nmr, epr, and ms results are given for the new compounds.

A Comparative Study on Reactions of Hydrogen Peroxide and Peracetic Acid with Lignin Chromophores. Part 1. The Reaction of Coniferaldehyde Model Compounds

Holzforschung ◽  
2000 ◽  
Vol 54 (2) ◽  
pp. 144-152 ◽  
Author(s):  
George X. Pan ◽  
Liam Spencer ◽  
Gordon J. Leary
Keyword(s):  
Hydrogen Peroxide ◽  
Peracetic Acid ◽  
Oxidation Products ◽  
Reaction Pathways ◽  
Main Reaction ◽  
Side Chain ◽  
Reaction Products ◽  
Efficient Utilization ◽  
Model Compounds ◽  
Rate Of Reaction

Summary The reactions of chromophoric model compounds of the coniferaldehyde type with hydrogen peroxide and peracetic acid have been investigated in relation to lignin-retaining bleaching. Analysis of the main reaction products indicated that the side chain of coniferaldehyde could cleave either between the α, β double bond or between the β, γ bond. Comparison of possible reaction pathways to the formation of oxidation products from hydrogen peroxide and peracetic acid suggested that peracetic acid is more effective than hydrogen peroxide. Advantages of peracetic acid over hydrogen peroxide include a faster rate of reaction, more efficient utilization of the bleaching agent and less likelihood of producing new chromophores.

Kinetics and Mechanism of the Homogeneous Oxidation of Quinaldine Red by Hydrogen Peroxide

2001 ◽  
Vol 215 (5) ◽  
Author(s):  
Ibrahim A. Salem ◽  
M. El-Maazawi
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Kinetics And Mechanism ◽  
Cationic Dye ◽  
First Order ◽  
Homogeneous Oxidation ◽  
Rate Of Reaction ◽  
Kinetics Of ◽  
Quinaldine Red

The kinetics of the oxidation of quinaldine red, a cationic dye, using hydrogen peroxide has been studied in aqueous solution. The rate of reaction was found to be first order in [quinaldine red] whereas in hydrogen peroxide it varies from one to zero with increasing [H

scholarly journals Kinetic Studies and Mechanism of Hydrogen Peroxide Catalytic Decomposition by Cu(II) Complexes with Polyelectrolytes Derived from L-Alanine and Glycylglycine

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Spyridon Skounas ◽  
Constantinos Methenitis ◽  
George Pneumatikakis ◽  
Michel Morcellet
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Rate ◽  
Aqueous Media ◽  
Catalytic Efficiency ◽  
Catalytic Decomposition ◽  
Kinetic Studies ◽  
Side Chain ◽  
First Order ◽  
Redox Pair ◽  
Ph Increase

The catalytic decomposition of hydrogen peroxide by Cu(II) complexes with polymers bearing L-alanine (PAla) and glycylglycine (PGlygly) in their side chain was studied in alkaline aqueous media. The reactions were of pseudo-first order with respect to [H2O2] and [L-Cu(II)] (L stands for PAla or PGlygly) and the reaction rate was increased with pH increase. The energies of activation for the reactions were determined at pH 8.8, in a temperature range of 293–308 K. A suitable mechanism is proposed to account for the kinetic data, which involves the Cu(II)/Cu(I) redox pair, as has been demonstrated by ESR spectroscopy. The trend in catalytic efficiency is in the order PGlygly>PAla, due to differences in modes of complexation and in the conformation of the macromolecular ligands.

scholarly journals III. The kinetics of ignition of carbon monoxide and oxygen sensitized by hydrogen

1938 ◽  
Vol 167 (930) ◽  
pp. 318-342 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Preceding Paper ◽  
Lower Pressure ◽  
Temperature Dependent ◽  
Pressure Limit ◽  
Catalytic Function ◽  
Rate Of Reaction ◽  
Hydrogen Mixtures ◽  
Kinetics Of ◽  
Combustion Of Hydrogen

The results of the preceding paper have revealed that in the presence of less than 1% of hydrogen, mixtures of carbon monoxide and oxygen assume many of the characteristics of oxy-hydrogen mixtures. In both systems ignition is possible over the same range of temperatures, and in each case is confined between upper and lower pressure limits outside which the rate of reaction falls abruptly to small values. It is reasonable to suppose that the catalytic function of hydrogen is primarily to impose a branching mechanism on the carbon monoxide reaction similar to that which operates in the combustion of hydrogen is primarily to impose a branching mechanism on the carbon monoxide reaction similar to that which operates in the combustion of hydrogen itself, and that since in each case reaction will be controlled by the same elementary temperature dependent process. The object of the present work was to investigate the extent to which participation of carbon monoxide in the reaction chains alters the characteristics of the branching mechanism as revealed by a study of the upper pressure limit of ignition.

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Kinetics of carbon monoxide methanation on a Ni/SiO2 catalyst

1990 ◽  
Vol 55 (7) ◽  
pp. 1678-1685
Author(s):  
Vladimír Stuchlý ◽  
Karel Klusáček
Keyword(s):  
Carbon Monoxide ◽  
Reaction Rate ◽  
Catalyst Activity ◽  
Adsorbed Hydrogen ◽  
Reaction Products ◽  
Co Methanation ◽  
Molar Ratios ◽  
Rate Determining Step ◽  
Higher Temperature ◽  
Kinetics Of

Kinetics of CO methanation on a commercial Ni/SiO2 catalyst was evaluated at atmospheric pressure, between 528 and 550 K and for hydrogen to carbon monoxide molar ratios ranging from 3 : 1 to 200 : 1. The effect of reaction products on the reaction rate was also examined. Below 550 K, only methane was selectively formed. Above this temperature, the formation of carbon dioxide was also observed. The experimental data could be described by two modified Langmuir-Hinshelwood kinetic models, based on hydrogenation of surface CO by molecularly or by dissociatively adsorbed hydrogen in the rate-determining step. Water reversibly lowered catalyst activity and its effect was more pronounced at higher temperature.

Oxidation of hydrocarbons in the liquid phase: n-dodecane in a borosilicate glass chamber at 200 °C

1969 ◽  
Vol 47 (22) ◽  
pp. 4175-4182 ◽  
Author(s):  
B. D. Boss ◽  
R. N. Hazlett
Keyword(s):  
Liquid Phase ◽  
Borosilicate Glass ◽  
Current Knowledge ◽  
Reaction Chamber ◽  
Cyclic Ethers ◽  
Reaction Products ◽  
Isomer Distribution ◽  
Oxidation Of Hydrocarbons ◽  
Volatile Products ◽  
Rate Of Reaction

The 5-h oxidation of n-dodecane at 200 °C by air at 1 atm is reported for experiments in a borosilicate glass reaction chamber equipped with a gas bubbler. The rate of reaction was limited by the rate of oxygen diffusion from the gas phase due to the rapid reaction of dissolved oxygen. The reaction products were analyzed in aliquots taken periodically from the reaction chamber. Chemical analyses, gas–liquid phase chromatography (g.l.p.c.), tandem g.l.p.c.-mass spectroscopy, infrared, and ultraviolet were used to identify products accounting for 98% of the oxygen reacted. The isomer distribution of the dodecenes, dodecanols, and dodecanones formed, as well as the distribution of carboxylic acids, were determined. Three classes of intramolecular reaction products, cyclic ethers, cyclic hydrocarbons, and lactones, were detected. Many volatile products were detected. A filterable precipitate obtained after 10 h of oxidation was studied using infrared attenuated total reflectance techniques. A reaction mechanism is discussed based on current knowledge of other systems, the products identified, and the stoichiometry of the reaction.

Sign in / Sign up

Export Citation Format

Share Document