KINETICS AND MECHANISM OF THERMAL REACTION OF ETHYLENE

Kinetics and mechanism of thermal reaction of ethylene were studied at temperatures ranging from 703° to 854° C. and at atmospheric pressure, with and without nitrogen dilution. The primary products were hydrogen, ethane, acetylene, propylene, 1-butene, and 1,3-butadiene. The secondary products were methane, cycloolefins, and aromatics. Partial pressure of ethylene affected the product distribution. A mechanism, proposed from kinetic evaluation of the relevant elementary reactions, could explain the formation of all the primary products. This mechanism suggested that product ethane was the initiator and product butadiene decreased the rates of formation of hydrogen, ethane, and butadiene, but not those of methane and propylene, by trapping active hydrogen atoms. This was confirmed by experimental results in the presence of a small quantity of added ethane and butadiene. Mechanisms of formation of cycloolefins and aromatics were evaluated. The rate of ethylene disappearance was expressed by a (-order equation with the rate constant k = 1011.73 exp (-49,600/RT), cc. × (mole sec.)-1. © 1969, American Chemical Society. All rights reserved.