Propene oxide, flames

With both flames, the formation of butadiene is strong evidence for the existence of C2H3 radicals. As no methanol was found in the propene oxide flames it was concluded that pyrolysis of the fuel... 

Examples for necessary process improvements through catalyst research are the development of one-step processes for a number of bulk products like acetaldehyde and acetic acid (from ethane), phenol (from benzene), acrolein (from propane), or allyl alcohol (from acrolein). For example, allyl alcohol, a chemical which is used in the production of plasticizers, flame resistors and fungicides, can be manufactured via gas-phase acetoxylation of propene in the Hoechst [1] or Bayer process [2], isomerization of propene oxide (BASF-Wyandotte), or by technologies involving the alkaline hydrolysis of allyl chloride (Dow and Shell) thereby producing stoichiometric amounts of unavoidable by-products. However, if there is a catalyst... 

Propane-propene oxidation Catalysts were characterized by activity measurements for hydrocarbon oxidation. Hydrocarbon oxidation was performed in a flow reactor system equipped with a flame ionization detector. The reactant mixture was composed of 0.2 % propene and 0.2 % propane ... 

HeybergerB, Battin-Leclerc F, Warth V, et al Comprehensive mechanism for the gas-phase oxidation of propene. Combust Flame 126(4) 1780—1802, 2001. 

S.G Davis, C.K. Law, and H. Wang. Propene Pyrolysis and Oxidation Kinetics in a Flow Reactor and Laminar Flames. Combust. Flame, 119 375-399,1999. 

Despite the kinetic objections to this scheme, which centred on the reaction sequence for the conversion of HO2 to -OH radicals, considerable support has been furnished for the role of the conjugate alkene as the primary product. Brown and Tipper [51] studied the oxidation of propane and cyclohexane at initial temperatures in the range 240—325 °C. With propane the amount of propene present just prior to the cool flame was considerable (ca. 10 % of the propane introduced) and additions of... 

VIV propene to equimolar mixtures of propane + oxygen reduced the cool-flame induction period by ca. 18 % at 300 °C. Like the previous work, these results showed the importance of the conjugate alkene in the autocatalytic oxidation of propane. However, at 247 °C, the yield of cyclohexene just prior to the cool flame was < 1 % of the total products. In contrast, at temperatures above 300 °C, it becomes the major product and is formed in roughly equal amounts with hydrogen peroxide prior to a stabilized cool flame [52]. Tipper concluded that above 300 °C reaction (2) occurs to an appreciable extent until well after the initial stage of oxidation since the differential yield of the alkene (d[C H2 ]/ d [C Hj 2 ]) was > 25 % over at least a quarter of the reaction. 

The composition and temperature profiles in low-pressure fuel-rich flames of ethylene oxide have been studied by Bradley et al. [65]. The major products were carbon monoxide, hydrogen, ethylene, methane, acetylene, butadiene and vinylacetylene, with traces of propene and propane. The unsaturated products were formed marginally later than the others, and ethane showed a maximum which coincided with the almost complete removal of fuel and oxygen. Acetylene and vinylacetylene continued to increase above the flame, although other products remained constant. 

This ester oxidizes very easily [95], reaction being perceptible even below 140 °C. Above about 300 °C, pyrolysis to propene and acetic acid also takes place. It too, gives cool flames [47]. Fish and Waris [95] detected only acetone, organic peroxides and peroxyacids in the products. Between 280 and 360 °C, Hoare and Kamil [97] found a wider range of products including hydrogen peroxide, formaldehyde, methanol, isopropanol, acetic acid and at 320 °C and below, acetaldehyde. Propene and acetone were found at 360 °C but organic peroxides and peroxyacids were always absent. 

Although these chemical analyses of propane oxidation [13] are among the best that have been reported, it is rather difficult to make a clear judgement from them on the applicability of the alkylperoxy radical mechanism of oxidation. There is reasonable evidence in support of enhanced yields of propene at higher temperatures, especially if allowance is made for the non-isothermal effects in cool-flames. The susceptibility of... 

Davis SG, Law CK, Wang H Propene pyrolysis and oxidation kinetics in a flow reactor and laminar flames. Combust Flame 119(4) 375-399, 1999. 

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