The substances oxidizers They are oxidizing substances that under specific conditions of temperature and pressure can react with a fuel and produce combustion. In this process, the oxidizer oxidizes the fuel and the fuel reduces the oxidizer. For instance: ozone, halogens, nitrates.
Oxidizers are oxidizing agents, prone to highly exothermic reduction-oxidation reactions (they produce heat), so many of these substances are considered among the dangerous or of careful handling, since they can cause serious burns.
Also called oxidizer, by extension, any medium in which combustion is possible. The best known oxidizer is oxygen.
The redox reactions (oxidation-reduction) are electronic transfer reactions between reactants, which produce changes in their oxidation states. Oxidizers are oxidants and therefore are reduced (meaning that they gain electrons when they participate in a redox reaction). In contrast, fuels are reducing, because they are oxidized (that is, they lose electrons during a redox reaction).
Examples of this type of reaction are explosion cases (in case the reaction is very fast and uncontrolled), chemical synthesis or corrosion.
Examples of oxidizers
- Oxygen (OR2). It is the oxidizer par excellence, involved in almost all flammable or explosive reactions. In fact, ordinary fire cannot occur in its absence. In general, redox reactions from oxygen produce, in addition to energy, quantities of CO2 and water.
- Ozone (OR3). It is an environmentally rare gaseous molecule, although abundant in the upper layers of the atmosphere. It is often used in water purification and other processes that take advantage of its strong oxidizing capacity.
- Hydrogen peroxide (H2OR2). Also known as hydrogen peroxide or dioxogen, it is a highly polar, highly oxidizing liquid, often used to disinfect wounds or bleach hair. Its formula is unstable and tends to break down into water and oxygen molecules, releasing heat energy in the process. It is not flammable but it can generate spontaneous combustion when it is in the presence of copper, silver, bronze or certain organic matter.
- Hypochlorites (ClO–). These ions are contained in numerous compounds such as liquid bleaches (sodium hypochlorite, NaClO) or powders (calcium hypochlorite, Ca (ClO)2), which are highly unstable and tend to decompose in the presence of sunlight and heat. They react very exothermically to organic matter (they can cause combustion) and to manganese (Mn), forming permanganates (MnO4–).
- Permanganates. They are salts obtained from permanganic acid (HMnO4), from which they obtain the anion MnO4– and therefore manganese in its highest oxidation state. They tend to have a powerful purple color and a very high flammability in contact with organic matter, which generates a purple flame that can cause serious burns.
- Peroxosulfuric acid (H2SW5). This colorless solid, meltable at 45ºC, has great industrial applications as a disinfectant and cleaner, and in the generation of acid salts in the presence of elements such as potassium (K). With organic molecules, such as ethers and ketones, it forms very unstable molecules through peroxidation, such as acetone peroxide.
- Acetone peroxide (C9H18OR6). Known as peroxyacetone, this organic compound is highly explosive as it reacts very easily to heat, friction or impact. For this reason, many terrorists have used it as a detonator in their attacks and many chemists have been injured when handling it. It is a highly unstable molecule, which is decomposed by an entropic explosion (reactants vary greatly in volume when reacting, without releasing too much heat).
- Halogens. Some elements of group VII of the periodic table, known as halogens, tend to form mononegative ions due to their need for electrons to complete their last energy level. Thus, salts known as halides are formed, which are highly oxidizing.
- Tollens reagent. Named by the German chemist Bernhard Tollens, it is an aqueous complex of diamine and silver ([Ag(NH3)2]+), of experimental use in the detection of aldehydes, since their powerful oxidizing capacity converts them into carboxylic acids. Tollens reagent, however, if stored for a long time, spontaneously forms silver fulminate (AgCNO), a highly explosive silver salt.
- Osmium Tetroxide (Bear4). Despite the rarity of osmium, this compound has many interesting applications, uses, and properties. In the solid state, for example, it is highly volatile: it turns into a gas at room temperature. Despite being a powerful oxidant, with multiple uses in the laboratory as a catalyst, it does not react with most carbohydrates, but it is highly poisonous in amounts less than those detectable by human smell.
- Perchloric acid salts (HClO4). Perchlorate salts contain chlorine in a high oxidation state, making them ideal for integrating explosives, pyrotechnic devices and rocket fuels, as they are a very poorly soluble oxidizer.
- Nitrates (NO3–). Similar to permanganates, they are salts in which nitrogen is in an important oxidation state. These compounds appear naturally in the decomposition of biological waste such as urea or some nitrogenous proteins, forming ammonia or ammonia, and are widely used in fertilizers. It is also an essential part of black powder, and uses its oxidation power to transform carbon and sulfur and release heat energy.
- Sulfoxides. Obtained mainly through the organic oxidation of sulfides, these compounds are used in numerous pharmaceutical drugs and in the presence of more oxygen they can continue their oxidation process until they become sulfones, useful as antibiotics.
- Chromium trioxide (CrO3). This compound is a solid of dark red color, soluble in water and necessary in processes of galvanizing and chromating of metals. Contact with ethanol or other organic substances produces immediate ignition of this substance, which is highly corrosive, toxic and carcinogenic, in addition to being an important part of hexavalent chromium, a highly harmful compound for the environment.
- Compounds with cerium VI. Cerium (Ce) is a chemical element of the order of lanthanides, a soft gray metal, ductile, easily oxidized. The different cerium oxides obtainable are widely used industrially, especially in the manufacture of matches and as a lighter stone (“tinder”) by means of an alloy with iron, since the mere friction with other surfaces is enough to produce sparks and usable heat. .