Slow oxidation of hydrocarbons and cool flames

1969 ◽  
Vol 73 (10) ◽  
pp. 3395-3406 ◽  
Author(s):  
Ching-Huan Yang ◽  
Brian F. Gray
Keyword(s):  
Cool Flames ◽  
Oxidation Of Hydrocarbons

The oxidation of hydrocarbons: studies of spontaneous ignition I. Ignition limits in small vessels

1965 ◽  
Vol 284 (1396) ◽  
pp. 108-124 ◽  
Keyword(s):  
Average Distance ◽  
Reaction Vessel ◽  
Spontaneous Ignition ◽  
Thermal Ignition ◽  
Chain Mechanism ◽  
Surface Parameter ◽  
Small Vessels ◽  
Cool Flames ◽  
Oxidation Of Hydrocarbons ◽  
Stage Process

Studies have been made of the spontaneous ignition of n -heptane+oxygen+inert gas mixtures at temperatures from 440 to 650°C, where ignition takes place by a one-stage process and no cool flames are observed. Detailed measurements have been made of the variation of minimum ignition pressure with such factors as the temperature, the composition of the mixture undergoing ignition and the nature, shape and extent of the surface of the reaction vessel. In particular, experiments in a wide variety of vessels show that the surface parameter which primarily determines the ignition tendency is the average distance of the molecules from the walls, rather than the surface:volume ratio. The quantitative relations observed experimentally are compared with the predictions of two isothermal chain-branching mechanisms involving distinct chemical paths and with the consequences of the theory of thermal ignition. It is shown that the results in small vessels (volume < 500 cm 3 ) are best explained in terms of an isothermal chain mechanism involving hydrogen peroxide as degenerate-branching agent, although in larger vessels thermal factors probably become increasingly important.

Low-temperature oxidation and cool flames of propane

1954 ◽  
Vol 221 (1145) ◽  
pp. 151-170 ◽  
Keyword(s):  
Low Temperature ◽  
Thermal Instability ◽  
Analytical Study ◽  
Simple Explanation ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Cool Flame ◽  
Cool Flames ◽  
Oxidation Of Hydrocarbons ◽  
Flame Oxidation

A detailed analytical study of the cool-flame oxidation of propane has been carried out using a continuous-flow technique with a view to the further elucidation of the mechanism of the low-temperature oxidation of hydrocarbons. The formation of the three theoretically possible aldehydes has been demonstrated and the initially formed peroxide shown to be hydrogen peroxide. Measurements of the yields of the different products formed under varying conditions of temperature, composition and time of contact have been made and correlated with measurements of the luminous intensity and temperature of the flame. The results confirm the earlier conclusions of Norrish (1948) that aldehydes are the important branching agents in the temperature range of 300 to 400°C, and a detailed scheme based on that proposed earlier has been developed to account for the observations. The scheme has further been shown to allow of a simple explanation of the origin of the periodic character of the cool flame in terms of the thermal instability of the normal slow reaction.

OXIDATION OF HYDROCARBONS AT LOW TEMPERATURES

Nature ◽  
1942 ◽  
Vol 149 (3787) ◽  
pp. 601-602 ◽  
Author(s):  
P. GEORGE ◽  
E. K. RIDEAL ◽  
A. ROBERTSON
Keyword(s):  
Low Temperatures ◽  
Oxidation Of Hydrocarbons

The Variation of Microbial (Methanotroph) Communities in Marine Sediments Due to Aerobic Oxidation of Hydrocarbons

2021 ◽  
Vol 20 (3) ◽  
pp. 553-561
Author(s):  
Jing Li ◽  
Changling Liu ◽  
Nengyou Wu ◽  
Xingliang He ◽  
Xiluo Hao ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Aerobic Oxidation ◽  
Oxidation Of Hydrocarbons

scholarly journals The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 336
Author(s):  
Deniz Zengel ◽  
Simon Barth ◽  
Maria Casapu ◽  
Jan-Dierk Grunwaldt
Keyword(s):  
Catalytic Reduction ◽  
Elevated Pressure ◽  
Systematic Investigation ◽  
Diesel Oxidation Catalyst ◽  
Zeolite Catalysts ◽  
Oxidation Catalyst ◽  
Pollutant Concentrations ◽  
Oxidation Of Hydrocarbons ◽  
Negative Effect ◽  
The Impact

Positioning the catalysts in front of the turbocharger has gained interest over recent years due to the earlier onset temperature and positive effect of elevated pressure. However, several challenges must be overcome, like presence of higher pollutant concentrations due to the absence or insufficient diesel oxidation catalyst volume at this location. In this context, our study reports a systematic investigation on the effect of pressure and various hydrocarbons during selective catalytic reduction (SCR) of NOx with NH3 over the zeolite-based catalysts Fe-ZSM-5 and Cu-SSZ-13. Using a high-pressure catalyst test bench, the catalytic activity of both zeolite catalysts was measured in the presence and absence of a variety of hydrocarbons under pressures and temperatures resembling the conditions upstream of the turbocharger. The results obtained showed that the hydrocarbons are incompletely converted over both catalysts, resulting in numerous byproducts. The emission of hydrogen cyanide seems to be particularly problematic. Although the increase in pressure was able to improve the oxidation of hydrocarbons and significantly reduce the formation of HCN, sufficiently low emissions could only be achieved at high temperatures. Regarding the NOx conversion, a boost in activity was obtained by increasing the pressure compared to atmospheric reaction conditions, which compensated the negative effect of hydrocarbons on the SCR activity.

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.

scholarly journals Chemisorbed Oxygen or Surface Oxides Steer the Selectivity in Pd Electrocatalytic Propene Oxidation Observed by Operando Pd Ledge X‐ray Absorption Spectroscopy

2021 ◽  
Author(s):  
Sergey Koroidov ◽  
Anna Winiwarter ◽  
Oscar Alfonso Diaz-Morales ◽  
Mikaela Gorlin ◽  
Joakim Halldin Stenlid ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Absorption Spectroscopy ◽  
Propene Oxidation ◽  
X Ray ◽  
Chemisorbed Oxygen ◽  
Oxidation Of Hydrocarbons ◽  
Surface Oxides ◽  
X Ray Absorption

Controlled electrochemical oxidation of hydrocarbons to desired products is an attractive approach in catalysis. Here we study the electrochemical propene oxidation under operando conditions using Pd L‐edge X‐ray absorption spectroscopy...

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