The Effect of the Molecular Structure on the Explosion Limits (Part 1)

Abstract

The explosion limits of C, monoolefins and C, C, dienes mixed with oxygen were determined by use of the admission method at the temperature below 600°C and reduced pressure in the range of 40-50 vol % of olefin, in order to study the relationships between the molecular structure and explosion behaviour of olefinic hydrocarbons. The results were compared with those of C₂C4 olefins.
The isochores for the explosion limits of C₂C5 monoolefins and C, C, dienes were grouped into three classes as shown in Table 1. The three types of the classification were originally proposed by Townend in the case of hydrocarbons-air mixtures at high pressure. These were Type 1, 2 and 3 shown in Fig.6. The isochores of Type 1 were further 'subdivided into Type A and Type B on the basis of the thermal explosion theory.
The effect of substituents on the types of the isochores was discussed. It was suggested that the initial step in the explosion reaction of monoolefins below 480°C was the formation of cyclic peroxide by direct addition of oxygen to C=C bond. The types of the isochores were explained in terms of the type of aldehydes on the basis of the reaction mechanism proposed above.