2- Butenes pyrolysis thermal decomposition

Decreased deactivation efficiency may also account for changing product ratios, such as increased formation of 3-methylbutene-l. Although Frey found no 3-methylbutene-l in photolysis experiments without added argon, this product was reported by Setser and Rabinovitch in pyrolysis of CH2N2-butene-2 mixtures and is also found to some extent in the thermal decomposition of 1,2-dimethylcyclopropane. It appears, therefore, that the formation of 3-methylbutene-l depends more on reaction conditions than on the electronic state of CH2. 

The photolysis or pyrolysis of diazoesters is the only source of carboalkoxy-carbenes and although numerous examples can be found in the literature concerning the reactivity of these carbenes, very little information is available on the kinetics of the decomposition. The photolysis of methyldiazoacetate yields carbo-methoxycarbene which adds stereospecifically to 2-butene. The quantum yield of the photolysis of ethyldiazoacetate has been determined in various solvents at different wavelengths (Table 12) . Thermal decomposition occurs above 150 °C although the presence of catalysts greatly accelerate the decomposition . Carboalkoxycarbenes are very selective with respect to insertion reactions, due to... 

The thermal decomposition of propylene involves a series of primary and secondary reactions leading to a complex mixture of products. Studies showed that the distribution of pyrolysis products varies considerably with the pyrolysis conditions and the type of reactor used. There is agreement among the studies on propylene pyrolysis that the three major products of pyrolysis are methane, ethylene, and hydrogen. However, there is disagreement on the types and amounts of minor or secondary product species. Ethane, butenes, acetylene, methylacetylene, allene, and heavier aromatic components are reported in different studies, Laidler and Wojciechowski (1960), Kallend, et al. (1967), Amano and Uchiyama (1963), Sakakibara (1964), Sims, et al. (1971), Kunugi, et al. (1970), Mellouttee, et al. (1969), conducted at different conversion and temperature levels. Carbon was also reported as a product in the early work of Hurd and Eilers (1943) and in the more recent work of Sims, et al. (1971). 

Neither the thermal nor the cobalt-catalyzed decomposition of 3-butene-2-hydroperoxide in benzene at 100 °C. produced any acetaldehyde or propionaldehyde. In the presence of a trace of sulfuric acid, a small amount of acetaldehyde along with a large number of other products were produced on mixing. Furthermore, on heating at 100°C., polymerization is apparently the major reaction no volatile products were detected, and only a slight increase in acetaldehyde was observed. Pyrolysis of a benzene or carbon tetrachloride solution at 200°C. in the injection block of the gas chromatograph gave no acetaldehyde or propionaldehyde, and none was detected in any experiments conducted in methanol. 

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