THE REACTIONS OF METHYLENE RADICALS WITH ACETALDEHYDE AND PROPIONALDEHYDE

1965 ◽  
Vol 43 (1) ◽  
pp. 106-118 ◽  
Author(s):  
M. H. Back
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Methyl Ethyl Ketone ◽  
Propylene Oxide ◽  
Methyl Ethyl ◽  
Temperature Range ◽  
Low Pressures

The reactions of methylene radicals with acetaldehyde and propionaldehyde have been studied over the temperature range 48–118 °C and over a range of pressures of aldehyde and carbon dioxide. From acetaldehyde, the main products were carbon monoxide, methane, ethane, and acetone, with small amounts of ethylene at low pressures of acetaldehyde. With carbon dioxide present, small amounts of propylene oxide were formed, but propionaldehyde was not observed. The main products from the reaction with propionaldehyde were carbon monoxide, methane, ethane, and ethylene, with small amounts of methyl ethyl ketone, butene oxide, and isobutyraldehyde. The relation of the results to the relative rates and mode of attack of methylene on the various bonds is discussed.

THE PHOTOLYSIS OF KETENE IN THE PRESENCE OF HYDROGEN

1956 ◽  
Vol 34 (2) ◽  
pp. 113-122 ◽  
Author(s):  
H. Gesser ◽  
E. W. R. Steacie
Keyword(s):  
Methyl Ethyl Ketone ◽  
Methyl Ethyl ◽  
Chain Reaction ◽  
Temperature Range ◽  
A Chain ◽  
Good Agreement

The photolysis of ketene in the presence of hydrogen has been investigated in the temperature range −40° to 207 °C. The main products are CO, C2H4, C2H6, and CH4, with some methyl ethyl ketone at the higher temperatures. Hydrogen and ketene compete for CH2 radicals by the reactions[Formula: see text]with E3 − E2 = 0.8 kcal. At the higher temperatures the reaction[Formula: see text]leads to a chain reaction via[Formula: see text]The value of E6 is found to be 10.2 ± 0.5 kcal. in good agreement with previous work.

THE LIQUID PHASE PHOTOLYSIS OF DIETHYL KETONE AND METHYL ETHYL KETONE

1958 ◽  
Vol 36 (2) ◽  
pp. 400-409 ◽  
Author(s):  
P. Ausloos
Keyword(s):  
Liquid Phase ◽  
Quantum Yield ◽  
Methyl Ethyl Ketone ◽  
Methyl Ethyl ◽  
Diethyl Ketone ◽  
Arrhenius Plots ◽  
Temperature Range ◽  
A Value ◽  
Recombination Reactions

The liquid phase photolysis of diethyl ketone has been studied in the temperature range from −35° to 95 °C. The CO quantum yield at 95 °C. was found to be close to unity. At 28 °C. decrease in intensity and addition of heptane led to a substantial increase of the CO and the ethane yields.The methyl ethyl ketone liquid phase photolysis at temperatures between 5° and 75 °C. led to the same observations. Arrhenius plots of RE/RB1/2[K] gave for both compounds a value of 5 kcal./mole.Gas phase studies in the temperature range of 0° to 60 °C. confirmed the low CO quantum yield reported previously and showed evidence for disproportionation and recombination reactions between ethyl and propionyl radicals.

Low-temperature partial oxidation of ethanol on Ni/ZnO catalyst

2019 ◽  
pp. 27-36
Author(s):  
N. V. Lapin ◽  
V. V. Grinko ◽  
V. S. Bezhok ◽  
A. F. Vyatkin
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Zinc Oxide ◽  
Nickel Catalyst ◽  
Partial Oxidation ◽  
Methane Content ◽  
Metallic Nickel ◽  
Molar Ratio ◽  
Temperature Range ◽  
Oxidation Of Ethanol

The paper investigates the partial oxidation of ethanol process in a quartz microreactor at atmospheric pressure in the temperature range 300–450 °C on a nickel catalyst (20 wt%) deposited on zinc oxide. Rectified ethanol (an azeotropic mixture of 95.6 wt.% ethanol and 4.4 wt.% water) is fed into the reactor at a rate of 0.4–1.3 g / hour by a peristaltic pump, first into the evaporator, and then as a gas phase into the reactor. Air is used as a source of oxygen which is supplied by an air pump to the reactor and its flow is controlled by a rotameter so that the oxygen-ethanol molar ratio varied between 0.45 and 2.0. The nickel catalyst is prepared by impregnating industrial zinc oxide powder with nickel nitrate, followed by calcination and reduction of nickel oxide to metallic nickel. Analysis of gaseous products is performed on a Tsvet-500 gas chromatograph. The detector is a katharometer.A catalyst Ni/ZnO developed earlier is shown to have high efficiency in the partial oxidation of ethanol at low temperatures. The main products of this process are hydrogen, methane, carbon monoxide and dioxide. With an increase in the oxygen-ethanol molar ratio, the hydrogen content in the products of the process decreases (from 60 to 25 vol.%), carbon dioxide, on the contrary, increases (26 to 65 vol.%). The hydrogen yield is 1 mol per 1 mol of ethanol at a temperature of 450 °C.Carbon monoxide is observed with a low ratio of oxygen-ethanol (up to 0.85). With a higher ratio, carbon monoxide is absent in the entire temperature range studied. The conversion of ethanol proceeds intensively and already at a temperature of 450 °C ethanol is converted almost completely. A high methane content (20–30% vol.%) in reforming products indicates that the initial stage of the process is the oxidation of ethanol followed by decomposition of the resulting acetaldehyde into methane and carbon monoxide.The insignificant water content in the supply mixture leads to an almost complete absence of a shift reaction. Carbon monoxide is then oxidized with oxygen to carbon dioxide. The reduced methane content in comparison with the process of water-steam ethanol reforming can be explained by its partial oxidation to carbon dioxide, which explains the high content of the latter in reforming products. 

Oxydation lente du cétène en phase gazeuse. II. Réaction à "basses températures"

1971 ◽  
Vol 49 (2) ◽  
pp. 303-306 ◽  
Author(s):  
Pierre Michaud ◽  
Cyrias Oueixet
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Low Temperature ◽  
Reaction Scheme ◽  
Phase Gazeuse ◽  
Temperature Range ◽  
Slow Combustion ◽  
Methyl Hydroperoxide

The slow combustion of ketene was investigated in the low-temperature range 280–350 °C. It differs from the reaction at higher temperatures chiefly by the presence of peroxides (mostly hydroperoxides) and the absence of methane. The main products: formaldehyde, carbon monoxide, water, and carbon dioxide are the same in both cases. A reaction scheme is proposed, which involves degenerate branching through the decomposition of methyl hydroperoxide: CH3OOH = CH3O• + •OH.

scholarly journals THE EFFECT OF LOW PRESSURES ON CELL OXIDATION

1930 ◽  
Vol 14 (1) ◽  
pp. 55-70 ◽  
Author(s):  
S. F. Cook
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Oxygen Uptake ◽  
Atmospheric Pressure ◽  
Anaerobic Respiration ◽  
Barometric Pressure ◽  
Carbon Dioxide Production ◽  
Partial Pressure Of Oxygen ◽  
Low Pressures

1. A method is described for measuring tissue oxidation under reduced barometric pressure. 2. The oxygen uptake of yeast is diminished by low barometric pressures to a greater extent than by a reduction of the partial pressure of oxygen, to a corresponding degree, at atmospheric pressure. 3. This effect of low pressure is not observed with certain in vitro oxidation systems. 4. The anaerobic respiration (carbon dioxide production) of yeast is not at all affected by low pressures. 5. The inhibition of tissue oxidation caused by carbon monoxide is removed by lowering the pressure.

The reaction of methanol vapour with silver(I) oxide

1964 ◽  
Vol 17 (5) ◽  
pp. 529
Author(s):  
JA Allen
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Gas Phase ◽  
Kinetic Data ◽  
Kcal Mole ◽  
Collision Model ◽  
Temperature Range ◽  
Methanol Vapour ◽  
The Mean

The reaction of methanol with silver(I) oxide has been studied in the temperature range 56.5-78.4�. For complete reduction of the oxide at 78.4�, the available oxygen is fully accounted for by the products, formaldehyde, formic acid, carbon monoxide, carbon dioxide, and water. In the temperature range 56.5-70.2� the net measured rates of formation of these products are expressed by equations of the form, ������������������ rate = Aexp(-E/RT), and the kinetic data are interpreted as the consecutive formation of the products on the surface without complete desorption to the gas phase between each step. For the dominant product, carbon dioxide, at the mean temperature the values of A and E are 1028.5 μg oxygen per minute and 41.3 kcal mole-1 respectively. The former is interpreted in terms of a simple collision model and the latter compared with values obtained for the thermal decomposition of the oxide.

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