PHOTOOXIDATION OF KETONES IN AN O18 ENRICHED ENVIRONMENT

1958 ◽  
Vol 36 (3) ◽  
pp. 421-424 ◽  
Author(s):  
J. R. Dunn ◽  
K. O. Kutschke
Keyword(s):  
Carbon Dioxide ◽  
Molecular Oxygen ◽  
Carbonyl Group ◽  
Low Temperatures ◽  
Large Fraction ◽  
Enriched Environment ◽  
Diethyl Ketone ◽  
Alkyl Groups

A technique is described in which the origins of the products of photooxidation of ketones can be obtained in respect to whether they arise from the carbonyl or the alkyl groups of the ketone molecule. This is accomplished with the use of reactant molecular oxygen which has been enriched in the O18 isotope. Application of this to the photooxidation of acetone indicates that a large fraction of the carbon dioxide contains the carbonyl group of the ketone and that acetyl radicals play an important role in the oxidation to temperatures at least as high as 175 °C. Propionyl radicals are much less stable, and, in the photooxidation of diethyl ketone, their reactions, other than decomposition, appear to be negligible at quite low temperatures. Some comment is made on the mechanisms of these photooxidations.

An Experimental Study of the Interaction of Multiple Liquid Pool Fires

1995 ◽  
Vol 117 (1) ◽  
pp. 37-42 ◽  
Author(s):  
J. R. Vincent ◽  
S. R. Gollahalli
Keyword(s):  
Carbon Dioxide ◽  
Large Fraction ◽  
Liquid Pool ◽  
Flame Height ◽  
Design Parameters ◽  
Pool Fires ◽  
Pool Surface ◽  
Flammable Liquids ◽  
Liquid Pools ◽  
Ignition And Combustion

The risk of accidental spills and possible fires is high in the storage and handling of large quantities of flammable liquids. Such liquid pool fires are generally buoyancy-driven and emit a large fraction of their heat release in the form of radiation. Ignition and combustion characteristics of liquid pools depend on the design parameters such as diameter, spacing, and shape of the pools. This laboratory scale study was conducted to determine the effects of these parameters on the characteristics of multiple liquid pool fires. The measurements reported include pool surface regression rate, flame height, temperature, and concentrations of carbon dioxide, soot, and oxygen.

The oxidation of Carbon with Atomic Oxygen

1959 ◽  
Vol 12 (2) ◽  
pp. 114 ◽  
Author(s):  
JD Blackwood ◽  
FK McTaggart
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Radio Frequency ◽  
Molecular Oxygen ◽  
Atomic Oxygen ◽  
Graphitic Carbon ◽  
Carbon Surface ◽  
Direct Oxidation ◽  
Radio Frequency Field ◽  
Frequency Field

Atomic oxygen, produced by dissociation of molecular oxygen in a radio frequency field, will react with amorphous or graphitic carbon at room temperatures and both carbon monoxide and carbon dioxide appear in the product gases. Carbon monoxide appears to be the primary product of oxidation of carbon, the carbon dioxide being produced by direct combination of carbon monoxide with oxygen which takes place mainly at the carbon surface. Atomic oxygen will also react with carbon dioxide to produce carbon monoxide and molecular oxygen but the quantity of carbon monoxide produced by this reaction is small compared to that produced by direct oxidation of the carbon.

STRUCTURAL AND SOLVENT EFFECTS ON THE n → π*(′U ← ′A) TRANSITIONS IN ALIPHATIC CARBONYL DERIVATIVES: EVIDENCE FOR HYPERCONJUGATION IN THE ELECTRONICALLY EXCITED STATES OF MOLECULES

1960 ◽  
Vol 38 (12) ◽  
pp. 2508-2513 ◽  
Author(s):  
C. N. R. Rao ◽  
G. K. Goldman ◽  
A. Balasubramanian
Keyword(s):  
Hydrogen Bonding ◽  
Carbonyl Group ◽  
Excited States ◽  
Solvent Effects ◽  
Electronically Excited States ◽  
Carbonyl Derivatives ◽  
Alkyl Groups ◽  
Electronically Excited

The n → π* transition of the carbonyl group has been studied in solvents of varying degree of polarity and hydrogen-bonding ability, in a number of aliphatic carbonyl derivatives. Evidence for hyperconjugation of the alkyl groups in the electronically excited states of molecules has been presented.

STUDY OF THE RADIOLYSIS OF BROMAL HYDRATE SOLUTIONS USING C14-LABELLED BROMAL

1959 ◽  
Vol 37 (7) ◽  
pp. 1127-1131 ◽  
Author(s):  
H. Heusinger ◽  
R. J. Woods ◽  
J. W. T. Spinks
Keyword(s):  
Carbon Dioxide ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Carbonyl Group

Bromal labelled with C14 in the carbonyl group has been used to show that small amounts of carbon dioxide and carboxylic acids are produced in the radiolysis of aqueous bromal solutions. G values for the production of CO2 and carboxylic acid are about 7.5% and 15% of those for HBr production, respectively. The observed yield of carboxylic acid is in agreement with that found by titration.

The photochemical and thermal decompositions of hydrogen sulphide

1953 ◽  
Vol 216 (1126) ◽  
pp. 344-361 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Quantum Yield ◽  
Hydrogen Sulphide ◽  
Low Temperatures ◽  
Room Temperature ◽  
Large Fraction ◽  
Kcal Mole ◽  
Hydrogen Atoms ◽  
Photochemical Decomposition ◽  
Bimolecular Mechanism

The photochemical decomposition of hydrogen sulphide has been investigated at pressures between 8 and 550 mm of mercury and at temperatures between 27 and 650° C, using the narrow cadmium line ( λ 2288) and the broad mercury band (about λ 2550). At room temperature the quantum yield increases with pressure from 1.09 at 30 mm to 1.26 at 200 mm. Above 200 mm pressure there was no further increase in the quantum yield. Temperature had little effect on the quantum yield at λ 2550, but there was a marked increase in the rate of hydrogen production between 500 and 650° C with 2288 Å radiation. This may have been caused by the decomposition of excited hydrosulphide radicals. The results are consistent with a mechanism involving hydrogen atoms and hydrosulphide radicals. The mercury-photosensitized reaction is less efficient than the photochemical decomposition, the quantum yield being only about 0.45. The efficiency increased with temperature and approached unity at high temperatures and pressures. This agrees with the suggestion that a large fraction of the quenching collisions lead to the formation of Hg ( 3 P 0 ) atoms. The thermal decomposition is heterogeneous at low temperatures and becomes homogeneous and of the second order at 650° C. The experimental evidence suggests the bimolecular mechanism 2H 2 S → 2H 2 + S 2 . The activation energies are 25 kcal/mole (heterogeneous) and 50 kcal/mole (homogeneous).

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