He Sodium permanganate Is a chemical compound of formula NaMnO 4 . It is available mainly in monohydrate form. Its structure is shown in figure 1.
This salt is hygroscopic and has a low melting point. It has the same properties as potassium permanganate (KMnO 4 ), Although sodium permanganate is about 15 times more soluble in water. Despite this, potassium permanganate is commonly used since its production costs are lower.
Figure 1: Structure of sodium permanganate.
Sodium permanganate readily dissolves in water to give deep purple solutions, the evaporation of which gives bright purple-black prismatic crystals of NaMnO4 · H2O monohydrate. The potassium salt does not form a hydrate. Due to its hygroscopic nature, it is less useful in analytical chemistry than its potassium counterpart.
It can be prepared by the reaction of manganese dioxide with sodium hypochlorite and sodium hydroxide or sodium carbonate in the following way:
2MnO 2 + 3NaClO + 2NaOH → 2NaMnO 4 + 3NaCl + H 2 OR
2MnO 2 + 3NaClO + Na 2 CO 3 → 2NaMnO 4 + 3NaCl + CO 2
Using sodium carbonate the yield is lower and the reaction must be heated to obtain the product (vapid, 2016).
Physical and chemical properties
Sodium permanganate has an appearance similar to potassium permanganate. They are prismatic crystals or purple spheres that in aqueous solution form a color liquid that goes from pink to purple depending on the concentration. Their appearance is shown in figure 2.
Figure 1: appearance of sodium permanganate
The anhydrous form of the compound has a molecular weight and a melting point of 141.9254 g / mol and 36 ° C respectively, and the monohydrate form has a molecular weight and a melting point of 159.94 g / mol and 170 ° C respectively.
Its density is 1,972 g / ml and it is very soluble in water, being able to dissolve 900g for each liter at room temperature (National Center for Biotechnology Information, 2017).
Reactivity and hazards
Sodium permanganate is not combustible, but it accelerates the combustion of combustible materials. If the combustible material is finely divided, the mixture may be explosive.
It may ignite spontaneously in contact with liquid combustible materials. Contact with sulfuric acid may cause fires or explosions.
Acetic acid or acetic anhydride can explode with permanganates if they are not kept cold. Explosions can occur when permanganates that have been treated with sulfuric acid come into contact with benzene, carbon disulfide, diethyl ether, ethyl alcohol, petroleum or organic matter (Sodium Incmanganate, 2016).
These substances accelerate burning when engaging in a fire. Some may decompose explosively when heated or involved in a fire. May explode due to heat or contamination.
Some will react explosively with hydrocarbons (fuels). It can ignite fuels (wood, paper, oil, clothing, etc.). Containers may explode when heated. Run-off may create a fire or explosion hazard (SODIUM PERMANGANATE, S.F.).
Potassium permanganate reacts with water to produce manganese dioxide, potassium hydroxide and oxygen. Potassium hydroxide is a strong corrosive. In severe cases, systemic effects may occur including intravascular coagulation, hepatitis, pancreatitis, and failure.
Chronic ingestion may cause paresthesias, tremors due to the toxicity of manganese. The neurotoxicity of manganese is the result of depletion of dopamine and neurotoxins, dopamine quinone and peroxide (SODIUM PERMANGANATE, 2014).
Sodium permanganate damages the ocular tissue on contact causing burns. It can be irritating to skin contact leaving purple spots on it. In case of inhalation it may cause damage to the respiratory tract (material data safety sheet sodium permanganate, S.F.).
If the compound comes into contact with the skin, it should be rinsed with copious amounts of water for at least 15 minutes while removing contaminated clothing and shoes.
In case of ingestion, do not induce vomiting. Loose clothing such as shirt collars, belt or tie should be loosened. If the victim does not breathe, mouth-to-mouth resuscitation should be given.
In case of inhalation, remove the victim from the exposure area and move to a cool place. If it does not breathe, artificial respiration should be given. If breathing is difficult, give oxygen.
In all cases, immediate medical attention should be obtained (Material Safety Data Sheet Sodium permanganate monohydrate, 2013).
Applications
Sodium permanganate, like the potassium compound, is a disinfectant and bactericidal antiseptic. Its uses include whitening resins, waxes, fats, straw, cotton, silk and other fibers and suede.
It is also used as a disinfectant, deodorant, chemical disinfectant in photography, and reagent in synthetic organic chemistry.
Illicit uses have included the production of drugs of abuse and abortion by topical application to the vaginal wall. Historically, solutions of permanganate have been used as a urethral irrigant and washing of liquid for poisoning.
Sodium Permanganate acts as an oxidizing agent in the oxidation of o-toluene sulfonamide to produce saccharin and purification of toluene amide. It is also an antidote to morphine and phosphorus, and synthetic organic / pharmaceutical reactions.
Sodium permanganate has been used in water treatment and soil rehabilitation because it is capable of degrading BTEX (benzene, toluene, ethylbenzene and xylene), phenols, polycyclic aromatic hydrocarbons (PAHs), chlorinated ethenes And explosives, and eliminate hydrogen sulfide.
Due to the high solubility in water, sodium permanganate is preferred for applications requiring high concentrations of permanganate ions, such as etching plastic parts of the printed circuit board.
Other uses of sodium permanganate include the metal surface treatment agent and the metal cleaning formulation, etc. (Sodium Permanganate Aqueous Solution (NaMnO4), S.F.).
Sodium permanganate may substitute for potassium permanganate in some applications, since it is the permanganate ion which is the oxidizing agent.
However, since sodium permanganate exists in monohydrate form, it can not be used for analytical applications such as redox titrations.
References
- Material data safety sheet sodium permanganate. (S.F.). Retrieved from dogee.org: dogee.org.
- Material Safety Data Sheet Sodium permanganate monohydrate. (2013, May 21). Retrieved from"science lab: science lab.com".
- National Center for Biotechnology Information. (2017, March 4). PubChem Compound Database; CID = 23673458. Retrieved from PubChem: pubchem.ncbi.nlm.nih.gov.
- SODIUM PERMANGANATE. (2014, December 5). Retrieved from toxnet: toxnet.nlm.nih.gov.
- SODIUM PERMANGANATE. (2016). Retrieved from cameochemicals: cameochemicals.noaa.gov.
- Sodium Permanganate Aqueous Solution (NaMnO4). (S.F.). Retrieved from changyuancorp: en.changyuancorp.com.
- SODIUM PERMANGANATE. (S.F.). Retrieved from chemicalbook: chemicalbook.com.
- (2016, June 27). Sodium permanganate from manganese dioxide and sodium hypochlorite. Retrieved from chemistry.stackexchange: chemistry.stackexchange.com.