Propylene reaction with cyclohexadiene

At 225°C, 5-allyl-l,3-cyclohexadiene equilibrates with tricyclo[3.3.1.0 ]nona-3-ene = 1.38 at 203°C) subsequently, 2-ally 1-1,3-cyclohexadiene and benzene and propylene were also formed presumably via a retro-ene reaction of the 5-allyl isomer (Scheme 10.54). " ... 

Thermal decomposition of 1-butene provides a more complex product spectrum than is obtained from either cis- or trans-2-butenes. Between 550° and 760°C in a flow system with nitrogen dilution (3), methane, propylene, butadiene, and ethylene were major products as well as hydrogen, ethane, 1-pentene, 2-pentene, 3-methyl-1-butene, and 1,5-hexa-diene. In studies in a static system (4), cyclohexadienes, benzene, cyclopentene, cyclopentadiene, toluene, orthoxylene, and cyclohexene were observed among the liquid products of the reaction over the temperature range 490°-560°C. 

Primary process (11) is also believed to proceed through a vibrationally excited ground-state molecule since it is also subject to pressure quenching, even at low pressures. This would fall in line with studies on the pyrolysis of l,S cyclohexadiene, which show that hydrogen, acetylene, ethylene, and benzene are products of the thermal reaction. Besides self-quenching, the use of inert gases such as xenon, carbon dioxide, propylene, and diethyl ether as quenchers has been investigated. ... 

From Figure 1, it is clear that the primary products of the thermal reaction of diallyl are ethylene, propylene, 1-butene, butadiene, 1-pentene, cyclopentene, cyclopentadiene, and 1,3,5-hexatriene, and the secondary products are 1,3-cyclohexadiene and benzene. Trace amounts of methane, propane, and 1,4-pentadiene were also found in some experiments. No hydrogen was detected by a nitrogen carrier gas chromatograph with MS 5A column. The formation of C 2 compounds was noticed at low temperatures. A small amount of liquid product was found in the separator tube after 50 or more experimental runs. The average molecular weight of the liquid product was 428 based on the method of Hill (15). 

---