Cool flames in the combustion of toluene and ethylbenzene

1956 ◽  
Vol 238 (1213) ◽  
pp. 143-153 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Light Intensity ◽  
Benzoic Acid ◽  
Aromatic Compounds ◽  
Flow System ◽  
Reaction Vessel ◽  
Static System ◽  
Cool Flame ◽  
Cool Flames ◽  
Blue Flame

The oxidation of toluene and ethylbenzene has been studied in a static system using a spherical reaction vessel (700 ml.) over the temperature range 300 to 500°C, and at total pressures up to 600 mm. Cool flames were observed in the oxidation of both hydrocarbons, but only the reaction of ethylbenzene gave rise to a ‘blue’ flame at higher temperatures. With neither hydrocarbon did periodicity in light intensity, or pressure pulses, occur. The ignition diagrams for 4 to 1 fuel + oxygen mixtures have been mapped out. With ethyl­benzene, the cool flame was maintained in a flow system, its spectrum was photographed and shown to be similar to that of fluorescent formaldehyde. The products of the reaction con­tained acetophenone, benzaldehyde and benzoic acid, phenol, quinol, hydrogen peroxide and methoxyhydroperoxide. The results have been compared with corresponding data for the oxidation of paraffin hydrocarbons, and it is concluded that, with both aromatic compounds, the processes allowing the possibility of cool-flame formation are themselves secondary in nature.

The peroxides formed during hydrocarbon slow combustion and their role in the mechanism

1961 ◽  
Vol 261 (1306) ◽  
pp. 388-401 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Atom ◽  
Flow System ◽  
Reaction Vessel ◽  
The Other ◽  
Dicarbonyl Compound ◽  
Hydroperoxide Decomposition ◽  
Peroxide Decomposition ◽  
Slow Combustion ◽  
Free Aldehyde

The peroxides formed during the slow combustion of five hydrocarbons in a flow system have been identified and the approximate yields estimated. With propane at 327°C and 2, 2, 3-trimethylbutane at 365 to 385°C the products contained only traces of hydrogen peroxide, its addition compounds with aldehyde and (with C 3 H 8 ) peracetic acid. With n -butane between 310 and 345°C and cylohexane between 290 and 316°C appreciable yields of peroxide were obtained (~ 10 to 20% of the hydrocarbon oxidized). These consisted of the monohydroperoxides, hydrogen peroxide and their addition compounds with aldehydes. With n -C 4 H 10 the relative amount of H 2 O 2 free and combined ( ~ 50% of the total peroxide yield) was much higher than with C 6 H 12 and some perpropionic acid was also detected. With n -heptane between 240 and 310°C the yield of peroxide in the products was also con­ siderable ( ~ 20% of the hydrocarbon reacted), and consisted mainly of dihydroperoxyheptane and its addition compounds with aldehydes (mainly formaldehyde), with much smaller amounts of monohydroperoxide and hydrogen peroxide (free and combined with aldehyde), diheptylperoxide and possible trihydroperoxyheptane. Packing the vessel increased the relative amount of aldehyde-addition compounds but did not affect the yield of free aldehyde, which apparently depended only on the temperature, being zero at 240°C. All aldehydes up to C 5 H 11 CHO were formed at higher temperatures, but those from C 3 to C 6 only in small yield. A little β -dicarbonyl compound and carboxylic acids were also detected in the products. The modes of formation and decomposition of the peroxides is discussed. It is suggested the dihydroperoxyheptane resulted from the abstraction of a hydrogen atom internally in the C 7 H 15 O 2 radical from the CH 2 group β or γ to the point of original attack, that aldehydes were produced partly by heterogeneous hydroperoxide decomposition and partly by decomposition of RO 2 radicals, and that with n -heptane the aldehyde-hydroperoxide compounds were formed mainly on the walls of the reaction vessel. Chain branching in the oxidation of propane and 2, 2, 3-trimethylbutane was presumably due exclusively to the oxidation of aldehydes formed, whereas with the other three hydrocarbons branching due to homo­geneous peroxide decomposition was probably important up to about 350°C.

Iodination of Aromatic Compounds Using Potassium Iodide and Hydrogen Peroxide

2008 ◽  
Vol 38 (22) ◽  
pp. 3894-3902 ◽  
Author(s):  
K. Suresh Kumar Reddy ◽  
N. Narender ◽  
C. N. Rohitha ◽  
S. J. Kulkarni
Keyword(s):  
Hydrogen Peroxide ◽  
Potassium Iodide ◽  
Aromatic Compounds

A mathematical model of the cool-flame oxidation of acetaldehyde

1971 ◽  
Vol 322 (1550) ◽  
pp. 377-403 ◽  
Keyword(s):  
Mathematical Model ◽  
Negative Temperature ◽  
Isothermal Oxidation ◽  
Limited Range ◽  
Detailed Model ◽  
Cool Flame ◽  
Induction Periods ◽  
Cool Flames ◽  
Satisfactory Account ◽  
Flame Oxidation

A detailed mathematical model of the non-isothermal oxidation of acetaldehyde has been found to give a realistic simulation of (i) single and multiple cool flames, their limits, amplitudes and induction periods; (ii) two-stage ignition; and (iii) the negative temperature coefficient for the maximum rate of slow combustion. A simplified form of the model, valid over a limited range of conditions, has been subjected to mathematical analysis to provide interpretations of the effects simulated by the detailed model. It is concluded that cool flames are thermokinetic effects often, but not exclusively, of an oscillatory nature, and that a satisfactory account of cool-flame phenomena must necessarily take reactant consumption into account.

ChemInform Abstract: Catalytic Hydroxylation of Benzoic Acid with Hydrogen Peroxide.

ChemInform ◽  
2010 ◽  
Vol 23 (49) ◽  
pp. no-no
Author(s):  
E. A. KARAKHANOV ◽  
CH. RETISH PULIPPURASSERIL ◽  
T. YU. FILIPPOVA ◽  
S. V. EGAZAR'YANTS ◽  
A. G. DEDOV
Keyword(s):  
Hydrogen Peroxide ◽  
Benzoic Acid

scholarly journals Nitric Oxide Circumstances in Nitrogen-Oxide Seeded Low-Temperature Powling-Burner Flames

2017 ◽  
Vol 3 (3) ◽  
pp. 157
Author(s):  
M. Furutani ◽  
Y. Ohta ◽  
M. Nose
Keyword(s):  
Nitric Oxide ◽  
Low Temperature ◽  
Hydrogen Cyanide ◽  
Chemical Species ◽  
Nitrogen Monoxide ◽  
Cool Flame ◽  
Spectrum Measurement ◽  
Temperature Development ◽  
Flame Region ◽  
Blue Flame

<p>Flat low-temperature two-stage flames were established on a Powling burner using rich diethyl-ether/ air or n-heptane/air mixtures, and nitrogen monoxide NO was added into the fuel-air mixtures with a concentration of 240 ppm. The temperature development and chemical-species histories, especially of NO, nitrogen dioxide NO<sub>2</sub> and hydrogen cyanide HCN were examined associated with an emission-spectrum measurement from the low-temperature flames. Nitrogen monoxide was consumed in the cool-flame region, where NO was converted to the NO<sub>2</sub>. The NO<sub>2</sub> generated, however, fell suddenly in the cool-flame degenerate region, in which the HCN superseded. In the blue-flame region the NO came out again and developed accompanied with remained HCN in the post blue-flame region. The NO seeding into the mixture intensified the blue-flame luminescence probably due to the cyanide increase.</p>

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