What is a comburent?
The term comburent refers to substances that can react with fuels to promote combustion reactions under certain conditions of temperature and pressure. This is because they are oxidizing substances, so they promote reduction-oxidation reactions.
By analogy, any medium through which combustion is possible is also called a comburent.
What are reduction-oxidation reactions?
Also known as redox reactions, reduction-oxidation reactions are electron transfers composed of two semi-reactions that occur simultaneously:
- Oxidation or loss of electrons.
- Reduction or acquisition of electrons.
The elements that are part of redox systems are called the oxidant and reducer. When the reaction takes place, oxidants are reduced and reducers are oxidized. While comburents are oxidizing elements, the fuels are reducing elements.
Redox reactions are exothermic reactions; this means they produce heat. That’s why oxidizers are hazardous substances, and they must be handled under strict safety conditions. Accidents with oxidizing agents can cause serious fires and burns.
If reduction-oxidation reactions occur very quickly, they will generate an explosion.
What are some examples of oxidizing substances?
- Oxygen: the comburent par excellence; involved in the vast majority of flammable and explosive reactions. The redox reactions in which it is involved generate energy, carbon dioxide, and water.
- Ozone: a gaseous molecule whose oxidizing power has wide applications in water purification processes.
- Hypochlorites: unstable ions that decompose in sunlight and in the presence of heat.
- Peroxyacetone (acetone peroxide): a highly unstable organic compound that reacts easily to heat, friction, or impact.
What are some applications of comburents?
Comburents are present in numerous natural and industrial processes of transforming matter, but some applications may include:
- Space industry: space shuttles have deposits of liquid dioxygen. This comburent makes combustion reactions possible in outer space, where the oxygen concentrations of the Earth’s atmosphere do not exist. On the other hand, in most land vehicles, combustion occurs thanks to atmospheric oxygen.
- Medicine: hydrogen peroxide is used in domestic and hospital settings for wound disinfection. On the other hand, sulphoxides are used in manufacturing a wide range of medicines, including antibiotics.
- Cleaning: peroxosulfuric acid is used as a disinfectant cleaner.
- Household combustion: some oxidizing agents, such as cerium, are used for manufacturing small-scale fire production materials and instruments in everyday situations, such as matches or tinder for lighters.