Chemical Education Today
Letters Comment on the Hazards of Peroxide Decomposition As a hydrocarbon specialist I read with some interest the letter in this Journal by J. B. Umland (1) and the response by M. C. S. de Mattos and D. E. Nicodem (2). The issue under discussion—the presence in ether of peroxides and their explosive decomposition—is an important one, and the correspondence referred to is focused on laboratory safety. I believe however that an interesting point of pedagogic value can be gleaned from it. There are two types of chemical explosive behavior: deflagration and detonation. The latter is by far the more powerful. In the teaching of hydrocarbon process safety at the Master of Science level I have made the point that although under laboratory conditions hydrocarbon–oxygen mixtures can be made to detonate, for example under rapid compression, hydrocarbon accidents in industry are almost always deflagrations. The types of combustion behavior observed in accidents involving hydrocarbons and their derivatives, including the boiling liquid–expanding vapor explosion (BLEVE), the vapor cloud explosion, the flash fire, the jet fire, and the pool fire, are all deflagrations. I have sometimes made the further point that the one possible exception to the view that detonations are not ex-
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pected from hydrocarbons or their derivatives under conditions of industrial processing is organic peroxides, which, if formed in significant quantities as side-products (perhaps during a partial oxidation process), can decompose explosively in such a way that a detonation ensues. This of course has to do with the presence of “intramolecular oxidant” and its effect on propagation rate, a point I raised in this Journal (3). I see a link between the point made there and the more recent correspondence cited. Perhaps more importantly, to draw the notice of readers to the possibility of detonation behavior with peroxides is to endorse Umland’s emphasis on their hazards. Literature Cited 1. Umland, J. B. J. Chem. Educ. 2002, 79, 1070. 2. de Mattos, M. C. S.; Nicodem, D. E. J. Chem. Educ. 2002, 79, 1070. 3. Jones, J. C. J. Chem. Educ. 2001, 78, 1596. J. C. Jones Department of Engineering University of Aberdeen Aberdeen AB24 3UE, UK
[email protected] Vol. 81 No. 2 February 2004
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Journal of Chemical Education
193
