Self Accelerating Decomposition Temperature - Results of Self-accelerating Decomposition

Results of Self-accelerating Decomposition

When thermal decomposition occurs some organic peroxide formulations release a considerable amount of gases and/or mists. Some, but not all, of these gases may be flammable. For example, carbon dioxide is a common, gaseous decomposition product for diacyl peroxides and peresters that is not flammable.

The decomposition may include small organic fragments such as methane or acetone which are flammable. When flammable gases or mists are released as part of the decomposition there is always the potential danger of a fire or vapor phase explosion. Therefore the risk of vapor phase explosion should be kept in mind when designing storage structures. These types of materials may be released at low rates during storage and in quite high rates in the event of an upset due to failure to control storage temperature or in the event of a fire in the storage area.

It is the ease of splitting the peroxy group to give two free radicals that makes organic peroxides so useful. However, the presence of energetic free radicals during decomposition, particularly in hot gases or mists, can cause auto-ignition to occur at a lower temperature than would otherwise be normal for a similar chemical structure without the peroxy functional group. Organic peroxides do not generally release oxygen as part of the decomposition so there is little risk of enhanced burning rates due to oxygen enrichment. This is unlike the decomposition of hydrogen peroxide and solid oxidizers that can liberate oxygen.