Explosion reaction of olefins

Abstract

The reaction mechanism is discussed on the basis of the relations between the explosion limits and the molecular structure. At the higher temperatures above ca 510℃, it is reasonably concluded that the initiation controls the explosion limits of olefins. Namely, the formation of OH radical according to the addition of an oxygen molecule to the C=C bond under around the equimolar composition, and the hydrogen abstraction by an oxygen molecule in the excess of oxygen, determine the explosion limits. The isochor curves of C_2～C_5 monoolefins at 50 and 60 vol % of oxygen can be grouped into three classes (type I, II and III) as shown in Table 1. It is suggested that acetaldehyde plays an important role in the shape of type III, and a co-operation between HCHO or CH_3CHO and higher aldehydes makes an important contribution to the shape of type II. In the case of olefins belonging to type II and III, the branching of aldehydes formed in the earlier stages at the lower temperatures below ca 480℃ controls the explosion limits.