Introduction
Potassium Permanganate KMnO4 is an inorganic chemical compound. It is also known as Condy’s crystals or permanganate of potash.
A German-Dutch chemist Johann Rudolf Glauber was the first to discover the production of KMnO4 in the year 1659. This compound is water-soluble and consists of two ions: Permanganate ion and potassium ion. It is a dark purple odourless solid in its physical state.
When potassium permanganate crystals are dissolved in water the solution formed is purple. It is considered as a strong oxidizing agent and does not produce toxic by products. It is usually prepared from other minerals such as manganese oxide.
1. Introduction to KMnO4
Potassium permanganate is broadly in use in the chemical industry and laboratories. It is in use as a strong oxidizing agent, and as a medication for dermatitis, for cleaning wounds, and also for general disinfection. Potassium permanganate is on the WHO Model List of Essential Medicines. Potassium permanganate is one of the safest and effective medicines needed in a health system.
In the year 1659,
A German-Dutch chemist Johann Rudolf Glauber was the first person to discover the production of potassium permanganate.
As if when potassium permanganate crystals are dissolved in water the solution becomes purple. Potassium permanganate is considered a strong oxidizing agent and does not give toxic by-products. Potassium permanganate is generally prepared from other minerals such as manganese oxide.
Preparation of KMno4 (Potassium Permanganate)
Potassium permanganate is made industrially from manganese dioxide. Manganese also occurs as the mineral pyrolusite. In 2000, worldwide production of potassium permanganate was 30,000 tonnes. The manganese dioxide is fused with potassium hydroxide and then heated in air or with another source of oxygen, such as potassium nitrate or potassium chlorate. This process results in potassium manganate.
2. Potassium Permanganate
1. Structure of Potassium Permanganate (KMnO4)
The structure of potassium permanganate molecules is illustrated below. Note that this compound features an ionic bond between the potassium cation and the permanganate anion.
2. Preparation Of Potassium Permanganate – KMnO4
Potassium permanganate is commercially prepared by mixing solution of KOH and powdered manganese oxide, with oxidizing agents like potassium chlorate. The mixture is boiled evaporated and the residue is heated in iron pans until it has acquired a pasty consistency.
6KOH + 3MnO2 + 6KClO3 → 3K2MnO4 + 6KCl + 3H2O
The potassium manganate (green) so formed is boiled with a large quantity of water and current of chlorine, CO2 and ozonized air is passed into the liquid until it is converted into permanganate. The MnO2 formed is removed continuously in order to prevent its breaking down the permanganate.
6K2MnO4 + 3Cl2 → 6KMnO4 (Potassium Permanganate) + 6KCl
The solution of KMnO4 is drawn off from any precipitate of MnO2 concentrated and crystallized. The crystals are centrifuged and dried.
3. Color
The purplish-black color of solid potassium permanganate, and the intensely pink to purple color of its solutions, is caused by its permanganate anion, which gets its color from a strong charge-transfer absorption band caused by excitation of electrons from oxo ligand orbitals to empty orbitals of the manganese(VII) center.
4. Clinical use
Potassium permanganate is used for a number of skin conditions.[10] This includes fungal infections of the foot, impetigo, pemphigus, superficial wounds, dermatitis, and topical ulcers.[11][10] Radioactive contamination of the skin can be cleaned with potassium permanganate and vigorous scrubbing. For topical ulcers it is used together with procaine benzylpenicillin.
[10] Typically it is used in skin conditions that produce a lot of liquid.[11] It can be applied as a soaked dressing or a bath.[12] It can be used in children and adults.[13] Petroleum jelly may be used on the nails before soaking to prevent their discoloration.[14]
For treating eczema, it is recommended using for only a few days at a time due to the possibility of it irritating the skin.[15]
The U.S. Food and Drug Administration does not recommend its use in the crystal or tablet form. It should only be used in a diluted liquid form.[16]
Historical use
Potassium permanganate was first made in the 1600s and came into common medical use at least as early as the 1800s.[17] During World War I Canadian soldiers were given potassium permanganate (to be applied mixed with an ointment) in an effort to prevent sexually transmitted infections.[18] Some have attempted to bring about an abortion by putting it in the vagina, though this is not effective.[19][20][21] Other historical uses have included an effort to wash out the stomach in those with strychnine or picrotoxin poisoning.
5. Side effects
Side effects from topical use may include irritation of the skin and discoloration of clothing.[23] A harsh burn on a child from an undissolved tablet has been reported.[24] Higher concentration solutions can result in chemical burns.[25] Therefore, the British National Formulary recommends 100 mg be dissolved in a liter of water before use to form a 1:10,000 (0.01%) solution.[26] [27][28]
Wrapping the dressings soaked with potassium permanganate is not recommended.[citation needed]
Potassium permanganate is toxic if taken by mouth.[29] Side effects may include nausea, vomiting, and shortness of breath may occur.[30] If a sufficiently large amount (about 10 grams) is eaten death may occur.[30]
Concentrated solutions when drunk have resulted in acute respiratory distress syndrome or swelling of the airway.[31] Recommended measures for those who have ingested potassium permanganate include gastroscopy.[31] Activated charcoal or medications to cause vomiting are not recommended. While medications like ranitidine and acetylcysteine may be used in toxicity, evidence for this use is poor.
6. Pharmaceuticals
In the United States the FDA requires tablets of the medication to be sold by prescription.[32] Potassium permanganate, however, does not have FDA approved uses and therefore non medical grade potassium permanganate is sometimes used for medical purposes.[citation needed]
It is available under a number of brand names including Permasol, Koi Med Tricho-Ex, and Kalii permanganas RFF.[33] It is occasionally called “Condy’s crystals”.[34]
7. Veterinary medicine
Potassium permanganate may be used to prevent the spread of glanders among horses.[35]
8. Synthesis of organic compounds
A major application of KMnO4 is as a reagent for the synthesis of organic compounds.[42] Significant amounts are required for the synthesis of ascorbic acid, chloramphenicol, saccharin, isonicotinic acid, and pyrazinoic acid.[36]
KMnO4 is used in qualitative organic analysis to test for the presence of unsaturation. It is sometimes referred to as Baeyer’s reagent after the German organic chemist Adolf von Baeyer. The reagent is an alkaline solution of potassium permanganate. Reaction with double or triple bonds (R2C=CR2 or R−C≡C−R) causes the color to fade from purplish-pink to brown. Aldehydes and formic acid (and formates) also give a positive test.[43] The test is antiquated.
9. Physical Properties Of Potassium Permanganate – KMnO4
- It is an odourless, purple to magenta crystalline solid.
- It is soluble in water, acetone, acetic acid, methanol, and pyridine.
- It gets dissolved in ethanol and organic solvents.
- Potassium permanganate occurs in the form of monoclinic prisms, almost opaque with a blue metallic lustre.
- It is odourless. An aqueous solution has a sweetish astringent taste. It is water-soluble and more soluble in boiling water.
10. Chemical Properties Of Potassium Permanganate
- Potassium permanganate is a very strong oxidizing agent and can, therefore, be used as an oxidant in a wide spectrum of chemical reactions.
- The oxidizing power of potassium permanganate can be seen while performing a redox reaction with it, in which the dark purple solution turns colourless and then into a brown solution.
- The above reaction can be performed in an acidic or a basic medium.
Reactions Of Potassium Permanganate (KMnO4)
1. Thermal decomposition:
When solid potassium permanganate is heated it undergoes decomposition. The reaction is as follows:
2KMnO4 → K2MnO4 + MnO2(s) + O2
2. Reaction with acid:
When permanganate reacts with concentrated hydrochloric acid it produces chlorine. In a neutral solution, permanganate is reduced by three electrons to produce manganese dioxide, where the oxidation state of manganese is +4. Potassium permanganate reduces spontaneously in an alkaline solution and turns into green K2MnO4.
3. Effect of Alkalies
On heating with alkalies, potassium permanganate changes into manganate and oxygen gas is evolved.
4KMnO4 + 4KOH → 4K2MnO4 + 2H2O + O2
4. Oxidizing properties
KMnO4 acts as a very powerful oxidizing agent in acidic, neutral and alkaline media. The equations representing oxidation in these media are
In acidic medium
2KMnO4 + H2SO4 → K2SO4 + 2MnSO4 + 3H2O + 5[O] MnO4– + 8H+ + 5e– → Mn2+ + 4H2O
In neutral or alkaline medium
2KMnO4 + H2O → 2KOH + 2MnO2 + 3[O] MnO4– + 2H2O + 3e– → MnO2 + 4OH–
5. Uses Of Potassium Permanganate (KMnO4)
There are wide applications of KMnO4. Some important uses of potassium permanganate have been discussed below:
- Potassium permanganate is used in qualitative analysis to determine the permanganate value
- KMnO4is also used as a regeneration chemical in well water treatment for the removal of hydrogen sulphide and iron
- This compound is also used as a disinfectant to cure certain skin conditions like foot fungal infections, dermatitis
- Another important application of potassium permanganate is in the treatment of bacterial infections
- KMnO4is also known to be used in tanning leathers, printing fabrics
- This compound can even be used as a bleaching agent, as a pesticide, and as an antiseptic
- One of the most important industrial applications of potassium permanganate is as an oxidizing agent in the chemical synthesis of many important compounds.
6. Effects on Health
- In a concentrated form, potassium permanganate is an irritant to human eyes and skin. It can react with many reducing agentsor organic material but it is inflammable.
- The antibacterial action of KMnO4 is dependent on the oxidation of proteins of bacteria or tissues by this compound. It leaves a stain on skin or tissues. Since it acts by destructive oxidation process on all organic matter, its use is restricted for external purposes only.
- Potassium permanganate acts as an antidote in barbiturates, chloral hydrate, and alkaloidal poisoning. A solution of 1:5000 of permanganate when used as a gastric wash, oxidizes poison and prevents their absorption.
- This compound is usually stored in tightly closed containers. Potassium permanganate should be handled with care since an explosion may occur when it comes in contact with readily oxidizable substances.
3. History
In 1659, Johann Rudolf Glauber fused a mixture of the mineral pyrolusite (manganese dioxide, MnO2) and potassium carbonate to obtain a material that, when dissolved in water, gave a green solution (potassium manganate) which slowly shifted to violet and then finally red.[65]
The reaction that produced the color changes that Glauber observed in his solution of potassium permanganate and potassium manganate (K2MnO4) is now known as the “chemical chameleon”.[66] This report represents the first description of the production of potassium permanganate.[67] Just under 200 years later, London chemist Henry Bollmann Condy had an interest in disinfectants; he found that fusing pyrolusite with sodium hydroxide (NaOH) and dissolving it in water produced a solution with disinfectant properties.
He patented this solution, and marketed it as ‘Condy’s Fluid’. Although effective, the solution was not very stable. This was overcome by using potassium hydroxide (KOH) rather than NaOH. This was more stable, and had the advantage of easy conversion to the equally effective potassium permanganate crystals.
This crystalline material was known as ‘Condy’s crystals’ or ‘Condy’s powder’. Potassium permanganate was comparatively easy to manufacture, so Condy was subsequently forced to spend considerable time in litigation to stop competitors from marketing similar products.[
4. Uses of Potassium Permanganate
Before delving into what is potassium permanganate used for, it’s worthwhile to learn about its origins. Also known as KMnO4, this compound is formed by combining manganese oxide ore with potassium hydroxide. Developed in 1857, it was originally intended as a disinfectant, but today it serves a wide range of applications. Here are some common uses of potassium permanganate:
1. Disinfectant
Potassium permanganate has potent antimicrobial properties, making it a highly efficient disinfectant for treating wounds, ulcers, and fungal infections. By directly applying diluted solutions of this compound to the affected areas, one can harness its antiseptic effects to combat pathogens and facilitate the healing process. This substance provides a reliable solution for maintaining hygiene and preventing the spread of infections, thereby establishing its value as an essential tool in healthcare settings and first aid practices.
2. Stain Removal
With exceptional stain-fighting capabilities, potassium permanganate is especially effective for removing specific types of stains, such as organic compounds like tannins, as well as iron and manganese stains. When applied appropriately, potassium permanganate acts as a powerful oxidizing agent, breaking down and eliminating these stubborn stains, revitalizing fabrics, and restoring the appearance of affected materials.
3. Water Treatment
Potassium permanganate can play a vital role in water treatment by getting rid of impurities and unpleasant odors. Its oxidation capabilities enable it to effectively eliminate organic compounds, iron, manganese, and hydrogen sulfide from water sources. By deploying potassium permanganate, water treatment processes can ensure the removal of these contaminants, resulting in cleaner, safer, and better-tasting water for various applications and consumption.
4. Laboratory Applications
In laboratory settings, potassium permanganate finds its use as an oxidizing agent, facilitating different kinds of chemical reactions. It proves helpful in titration procedures, organic synthesis endeavors, and redox reactions, where its oxidative properties play a crucial role. Whether in determining the concentration of substances, synthesizing organic compounds, or driving redox transformations, potassium permanganate stands as a reliable tool for scientists and researchers, enabling the advancement of various fields of study.
5. Fire Starter
A scenario where potassium permanganate used for fire starting is when it’s combined with substances like glycerin or sugar. This unique mixture has the ability to spontaneously ignite, making it one of the preferable survival tools. By harnessing the power of this compound and the appropriate materials, one can quickly generate a flame when faced with challenging circumstances where ignition is much-needed.
6. Aquarium Maintenance
In the world of fishkeeping and aquarium maintenance, potassium permanganate can provide an effective solution for treating a range of parasitic conditions, including ich (white spot disease), flukes, and external infections in fish. By eliminating harmful pathogens, it serves as a potent remedy that can be administered through bathing or dipping affected fish. Due to this benefit, aquarium enthusiasts use potassium permanganate to promote the overall health and vitality of their aquatic companions.
7. Horticulture
The uses of potassium permanganate extend to the fields of gardening and horticulture, offering the ability to combat fungal diseases, disinfect plant material, and eliminate algae from irrigation systems. Its powerful oxidizing properties help control the spread of harmful fungi, ensuring healthier plants. Additionally, it serves as a potent disinfectant, safeguarding plant cuttings and tools against contamination. When applied to irrigation systems, it effectively eliminates algae, preventing clogs and ensuring the smooth flow of water for optimal plant hydration. Its multifaceted uses make it a great asset in maintaining thriving horticultural environments.
After knowing what is potassium permanganate used for, It’s important to note that potassium permanganate is a strong oxidizing agent and should be handled with care. It can stain and cause burns, so proper precautions should be taken when using it.
Leprosy and Tropical Diseases
Hugh Cross, Francisco Vega-López, in Neale’s Disorders of the Foot and Ankle (Ninth Edition), 2020
Management and treatment
Mild infections are successfully treated by bathing or soaking the affected foot in potassium permanganate solution (1:10,000 dilution in water) for 15 minutes daily. Other mild superficial infections, such as isolated plaques of impetigo or impetiginised eczema, respond well to antiseptic or antimicrobial creams and ointments containing cetrimide, chlorhexidine, fucidic acid or mupirocin.
Acute or chronic foot eczema requires treatment with potent topical steroids in order to eliminate risk factors for infection. Infections with multiple lesions, or those involving larger areas of the foot, require a complete course of systemic β-lactam or macrolide antibiotics in addition to the above topical treatments.
Recurrent episodes of cellulitis require longer courses of these antibiotics, and hospitalisation followed by surgical debridement is mandatory in necrotic lesions, gangrenous plaques and deeper infections with severe fasciitis. Superficial infections of the foot skin complicated by deeper involvement with necrosis of soft tissues carry a high mortality rate (up to 25%) (Elliot et al 1996).
Question
What is the use of KMnO4 potassium permanganate?
Potassium permanganate is widely used in the chemical industry and laboratories as a strong oxidizing agent, and also as a medication for dermatitis, for cleaning wounds, and general disinfection. It is on the World Health Organization’s List of Essential Medicines.
What is another name for KMnO4?
Potassium permanganate
Potassium permanganate, also known as permanganate of potash or Condy’s crystals, is a chemical compound with a chemical formula of KMnO4, made of a potassium (K+) ion and a permanganate (MnO4-) ion.
What is the benefit of potassium permanganate?
Potassium permanganate is used as a topical preparation for the care of wound or skin conditions in the community and hospital setting. Potassium permanganate is classed as ‘an oxidising agent’ which is thought to confer bactericidal properties.
Is potassium permanganate safe in drinking water?
Hence, Potassium permanganate is used for purifying drinking water because it is an oxidizing agent. Option D is the required answer. Note: Potassium permanganate must be diluted since undiluted solution may cause burns. Even with dilution it may irritate the skin, if repeatedly used may still cause burns.
Why is KMnO4 purple in color?
Due to charge transfer reaction within the molecule, photons promote an electron from the highest energy MO orbital in one of the Mn-O bonds to an empty d orbital of Mn. This promotion is equivalent to the energy of a yellow photon, so yellow light is absorbed and make us to see as its complementary colour purple.
Is potassium permanganate harmful to skin?
Side effects
The most common side effect of potassium permanganate is dryness of the skin at the treated area. Potassium permanganate can cause irritation or burns if the tablet is split or cut, not fully dissolved or the solution is not diluted enough.