Potassium permanganate

Strong oxidizing agent

Potassium permanganate has strong oxidation and is often used as oxidants in the laboratory and industry, being sweet and astringent and is soluble in water with the solution being purple. It will undergo decomposition immediately when coming across ethanol. In acidic medium, it will be slowly decomposed into manganese dioxide and oxygen. Light has catalytic effect on this decomposition, so often be stored in brown bottles in the laboratory. From the element potential diagram and the oxidation state diagram of free energy, it can be seen of having a strong oxidizing effect. In the alkaline solution, its oxidation property is not as strong as that in the acidic condition. As the oxidant, the reduction product can be different according to the difference of acid-base property in different media.

This product, upon coming across of organic matter, can release nascent oxygen and manganese dioxide with no free oxygen atoms being released, thus there is no bubbles. The initial ecological oxygen has sterilization, deodorant, and detoxification effect. The antibacterial deodorant effect of the potassium permanganate is stronger and more long-lasting than that of the hydrogen peroxide solution. Manganese dioxide can be combined with protein to form salt with convergence effect at a low concentration but stimulation and corrosion effect at high concentrations. The bactericidal power increases with the concentration with 0.1% being able to kill the majority of bacterial propagules while 2% to 5% solution being able to kill bacterial spores in 24 hours. In acidic conditions, the bactericidal effect is significantly improved. For example, addition of 1.1% hydrochloric acid to the 1% solution can kill the anthrax spores in 30 seconds.
It is commonly used of 0.1% solution for administration orally for the treatment of cattle and sheep forestomach flaccid, acute gastroenteritis of horse and other animals and diarrhea. Apply 0.01% solution for the drinking of young bird. External administration of 0.1% solution can be used to wash the mucous membrane and treatment of skin trauma, ulcers and so on. Oral administration of the 0.05%~0.1% solutions can be used for the treatment of certain organic poisoning; 1% solution can be used for washing the wound caused by snake bites. Application of the 4~5mg per liter of potassium permanganate solution for the whole pond spill can be used for the treatment of fish water mold and protozoa, crustaceans and other parasites. Bath at a concentration of 100mg per liter of for 30 minutes can be used for the treatment of salmon egg membrane malacia. It is commonly applied of 0.1%~0.12% solutions for disinfection of the hive contaminated by the virus and bacteria. Potassium permanganate and formalin can be used in combination, can be used for the air fumigation disinfection of livestock (poultry) homes, and incubators.

Pharmacological effects

It can exhibit bactericidal effect through oxidation of the active group of bacteria. The potassium permanganate can effectively kill a variety of bacterial propagules, fungi, Mycobacterium tuberculosis; being able to also inactivate the hepatitis B virus and spores, but the effect on spore requires a longer time. Heating of organic matter, acidic or alkaline conditions can both accelerate the oxidation reaction. The oxidation reactions at different pH conditions are also different. In the acidic solution, it is reduced to a colorless divalent manganese compounds itself; in the neutral or alkaline solution, it was reduced to brown manganese dioxide and protein complex precipitation. At low concentration, it has antibacterial, convergence, bleeding, deodorant and other effects. At high concentrations, it is irritating and corrosive with its antibacterial effect being stronger than hydrogen peroxide. It is clinically mainly used for the treatment of acute dermatitis or acute eczema (especially with secondary infection), cleaning ulcers or abscess, for gastric larva upon oral administration of morphine, opiates, brucine or organic poisoning and first-aid treatment upon snake bites. It can also used for the disinfection of fruits, utensils and other stuffs. Mouth administration is applicable to the treatment of Candida albicans infection, necrotizing gingivostomatitis, periodontal rinsing. Contact of potassium permanganate with clothing will leave brown traces which can be removed through adding oxalic acid to water for scrubbing.
Oral intake of potassium permanganate solution can cause a series of symptoms of gastrointestinal irritation, such as oropharyngeal burning sensation, swelling, nausea, vomiting, stomach pain, severe speech, swallowing and breathing difficulties; proteinuria can also occur. It has a lethal dose of 10g. Solution should be fresh formulated with being reduced for failure after a little longer time. It is not suitable to be treated together with the reducing agent such as glycerin, iodine and sugar in order to prevent the explosion. High concentrations are irritating to the skin.

The effect of different concentrations of sterilization solution

Potassium permanganate is a strong oxidant, also known as gray manganese oxide, PP powder, appearing as dark purple small crystals with a metallic luster at room temperature. It will exert the oxidation effect when coming across organic matter. Therefore, it can not only disinfect, but also be deodorant. Low concentration has convergence effect. For livestock and poultry drinking, it can often be adjusted to 0.1% aqueous solution for gastric lavage and poison oxidation for detoxification. High concentration of the solution has irritating and corrosive effect on the tissue with 4% solution being able to disinfect feeding trough and other appliances. Taking advantage of its oxidation properties to accelerate formalin evaporation can be used for air disinfection, being commonly used disinfectant for the family.
1. Deep purple solution (about 0.3% concentration): has strong oxidative property and strong bactericidal capability. Can be used for disinfection bath, spittoon.
2. Purple red solution (about 0.05% concentration): anti-itching, anti-inflammatory and anti-infection, can be used for dipping tinea pedis.
3. Rose red solution (about 0.01% concentration): disinfection of fruits and vegetables and tableware. For disinfection of appliances, it can be applied of 1: 1000 potassium permanganate powders for soaking of 15 minutes, followed by rinsing with running water. Fruit and vegetable, after contamination by bacteria, can be subject to the soaking with this concentration of the solution for 5 minutes to sterilize without changing the color and taste of fruits and vegetables. In the medical industry, solution of this concentration can be used for rinsing the mucosal parts, such as hemorrhoids, having anti-infection, anti-itching and anti-pain and other effects.
4. Light cherry red solution (about 0.002% concentration): can be used to gargle to prevent oral inflammation and dental caries, having deodorant anti-inflammatory effect and being able to help to reduce the indecent underarm. It can also used for the antidote. After drinking the concentration of solution, pressure with your fingers on throat for vomiting and spit the unabsorbed drugs or poison. The stomach residues drugs or toxicants will be subject to potassium permanganate oxidation and failure.
Note: Use cold water for preparation of aqueous solution. Hot water will break down it to cause failure. The prepared water solution can usually be only saved for about two hours. When the solution exhibits brown purple color, it will lose disinfection effect. It is better to prepare fresh one upon using.

Solubility in water (g / 100ml)

Dissolved grams per 100 ml of water at different temperatures (° C):
30 ° C; 30 ° C/40 ° C; 4,3 g /
22.1 g/60 ° C

Content analysis

Take 0.3 g of sodium oxalate pre-dried at 105~110 ℃ dried to constant weight (accuracy: 0.0002g) to dissolve in 100ml of water. Add 6 mL of 1: 1 sulfuric acid solution. Use test rod to take another 3.3g (called quasi-to 0.0002g) to dissolve in water before the constant volume to 1000ml (brown volumetric flask), shake and place in the dark for 1h. Take the supernatant and add into the burette; add first drop of 38ml sample solution into the sodium oxalate solution and heat to 70~75 ℃, continue to drop to until solution becomes pink without fading within 30 s which can be treated as the end point. A blank test was also performed to correct the results.
KMnO4 (%) = W × 0.4717/G × V1-V2/V3 × 100, Where
W-the amount of the oxalate, g; G-volume of sample, g; V1-the volume of sample solution consumed when titrating sodium oxalate, in ml; V2-the amount of sample solution consumed in the blank test Ml; V3-the total volume of the sample solution, ml; 0.4717-1g sodium oxalate is equivalent to the quality of potassium permanganate, sodium oxalate.
The difference between the results of the parallel determination should not be greater than 0.2%.

Uses

1.    It can be used as oxidant, bleach, carbon dioxide refined beverage, deodorant, wood preservatives, adsorbents, disinfectants, pesticides, water purifiers, etc.
2.    It can be used as the bleaching agent, oxidant and disinfectant. China provides that it can be used for the production of starch and wine with the maximum usage amount of 0.5g/kg; the wine residue (calculated on manganese) should not exceed 0.002g/kg.
3.    In the chemical production, it is widely used as oxidants, such as oxidant for the manufacturing of sugar, vitamin C, isoniazid and benzoic acid; in medicine, it can be used as a preservative, disinfectant, deodorant and antidote; in water purification and wastewater treatment, it can be used as water treatment agent for oxidation of hydrogen sulfide, phenol, iron, manganese and organic, inorganic and other pollutants for odor control and decolorization; in gas purification, it can be used to remove trace sulfur, arsenic, phosphorus, silane, borane and sulfide; in the mining and metallurgy, it can be used for the separation of molybdenum from copper, removing the impurity in zinc and cadmium and the oxidant of compound flotation; it can also be used for the bleaching agent of special fabrics, wax, grease and resin and the absorbent of gas masks and wood and copper coloring agent. Food grade product can be used as bleaching agent, disinfectant, deodorant, water purification agents and refining agent of carbon dioxide beverage.
4.    Disinfection antiseptic agent;
5.    It can be used as analytical reagent, redox titrant, chromatographic analysis reagent, oxidant and pesticide, also used in organic synthesis

Production method

Calcination method
Potassium hydroxide is subject to melting dehydration and mixed with soft manganese powder. After being cooled and crushed, at a temperature of 240 °C, it absorbs oxygen in the air and subject to slowly oxidation calcination for being converted into potassium permanganate. After leaching with water or dilute solution, perform filtration and prepare electrolyte solution with the composition of: 160~180 g/L potassium manganate. Potassium hydroxide (free): 45~60 g/L, potassium carbonate <60 g/L. Electrolysis end point: control the electrolyte composition at: 40~60 g/L potassium permanganate; potassium hydroxide (free) 90~110 g/L and obtain the potassium permanganate crude product by centrifugal separation, followed by recrystallization, centrifugal separation and drying to obtain the finished product of potassium permanganate. Its reaction is:
4KOH + 2MnO2 + O2 → 2K2MnO4 + 2H2O
2K2MnO4 + 2H2O [electrolysis] → 2KMnO4 + 2KOH + H2 ↑
The mother liquor after the centrifugal separation is evaporated to recover the potassium manganate and causticized to recover the potassium hydroxide.
Liquid phase oxidation method:
Potassium hydroxide is subject to preheating, and blown of oxygen-enriched air or air at above 200 °C for liquid-phase oxidation with soft manganese powder. The manganese dioxide is first subject to oxidation to potassium manganous, and then further oxidized into potassium manganese. The concentration of potassium hydroxide is controlled at 60%~70%, and the mole ratio of manganese hydroxide to manganese dioxide is (30~60): 1. Potassium manganate is subject to sedimentation separation. Recover the potassium hydroxide in the upper layer, followed by crystallization, filter-pressing and dissolving with electrolytic mother liquor. Further add calcium hydroxide solution for causticizing, and then prepare electrolyte solution for electrolysis after the filter-pressing. The potassium permanganate crude product is subject to centrifugal separation, and then by recrystallization, centrifugal separation and drying to obtain the finished product of potassium permanganate finished. Its reaction is:
2MnO2 + 6KOH + 0.5O2 → 2K3MnO4 + 3H2O
2K3MnO4 + 0.5O2 + H2O → 2K2MnO4 + 2KOH
2K2MnO4 + 2H2O [electrolysis] → 2KMnO4 + 2KOH + H2↑
The mother liquor after centrifugal separation should undergo evaporation for recovery of potassium permanganate, followed by caustic recovery of potassium hydroxide.

Toxicity

It has an irritating effect on the eyes, being able to stimulate the mucous membrane and make the eye medium be colored. Upon splashing, it should be promptly to add drop wise into eye of 1% hydrogen peroxide and 1% acetic acid to discolor the colored eye.
For other information, see “metal Manganese”.

Chemical properties

It appears as red purple rhomboid, granular or needle-like crystals with metallic luster. It can be dissolved in water into a deep purple-red solution, slightly soluble in methanol, acetone and sulfuric acid.

Hazards & Safety Information

Category: oxidant
Toxic classification: poisoning
Acute toxicity Oral-Rat LD50: 1090 mg/kg; Subcutaneous-Mouse LD50: 500 mg/kg
Explosive and hazardous properties being explosive upon coming across organic matter, reducing agent, sulfur, phosphorus and other flammable materials.
Flammability and hazardous characteristics high heat causes decomposition of oxygen; being combustible in case of organic matter, reducing agent, sulfur, phosphorus and other flammable product with combustion generating toxic manganese-containing smoke
Storage and transportation characteristics Treasury: ventilated, light loading and unloading; store it separately from organic matter, reducing agent and sulfur phosphorus.
Fire extinguishing agent mist water, sand
Occupational Standard TWA 5 mg (Mn)/m3; STEL 6 mg (Mn)/m3

Description

Potassium permanganate, is composed of dark purple, odorless crystals with a blue metallic sheen. It is soluble in water, decomposes at 465°F (240°C), and is a powerful oxidizing material. Potassium permanganate is a dangerous fire and explosion risk in contact with organic materials. Potassium permanganate is incompatible with sulfuric acid, glycerin, and ethylene glycol. The four-digit UN identification number is 1490. The primary uses of potassium permanganate are as an oxidizer, bleach, or dye; during radioactive decontamination of the skin; and in the manufacture of organic chemicals.

Chemical Properties

Potassium permanganate, permanganate of potash KMnO4, purple solid, soluble, formed by oxidation of acidified potassium manganate solution with chlorine, and then evaporating.

Chemical Properties

Potassium permanganate is a dark purple crystalline solid with a sweet taste that decompose at 240°C and explode in contact with oxidizable materials.Used as a disinfectant and analytical reagent, in dyes,bleaches,and medicines,and as a chemical intermediate.

Physical properties

Dark purple rhombohedral crystal; density 2.703 g/cm³; stable in air;decomposes at about 240°C; moderately soluble in cold water, 6.38 g/100mL at 20°C, soluble in hot water, 25 g/100mL at 65°C; decomposed by alcohol, acetone and many organic solvents causing their oxidation; also decomposed by concentrated acids.

Electrical Conductivity

Uses

Potassium permanganate (KMnO4) is a dark purple-bluish sheen crystal with a slightly sweet taste. It is produced by oxidizing manganate in an electrolytic cell or by passing carbon dioxide through a hot solution of manganate and then cooling until permanganate crystals form. It is a strong oxidizing agent, particularly with organic matter, which makes it a good disinfectant, deodorizer, bleach, and antiseptic.

Uses

Bleaching resins, waxes, fats, oils, straw, cotton, silk and other fibers and chamois skins; dyeing wood brown; printing fabrics; washing CO2 in manufacture of mineral waters; exterminating Oidium tuckeri; photography; tanning leathers; purifying water; with formaldehyde solution to expel formaldehyde gas for disinfecting; as an important reagent in analytical and synthetic organic chemistry.

Uses

Potassium permanganate (KMnO4) is a purplish crystal-like oxidizing compound used as an antiseptic and disinfectant to inhibit the growth of harmful skin microorganisms and bacteria. Before antibiotics were available, it was used as a treatment for trench mouth and impetigo.
Trench mouth (necrotizing ulcerative gingivitis), also called “Vincent’s infection,” usually affects young adults and is considered a form of periodontal disease. If untreated, it can lead to the loss of gum tissue and eventually loss of teeth. Today, there are more effective treatments for trench mouth than KMnO4.

Indications

Potassium permanganate (KMnO4) is an oxidizing agent that is rapidly rendered inactive in the presence of organic material. The oxidizing action of the chemical is purportedly responsible for its germicidal activity. It is also an astringent and a fungicide. This preparation stains the skin and clothing, and undissolved crystals will cause a chemical burn. It is used less commonly now (primarily as an antifungal agent) and may be little better than water as a wet dressing. A 1:4,000 to 1:16,000 dilution is used on weeping or denuded surfaces (one crushed 65-mg tablet dissolved in 250 to 500 mL; one 330-mg tablet dissolved in 1,500 mL to 3,000 mL). For use as a medicated bath, 8 g (approximately 2 tsp) should be dissolved in 200 L (a full bathtub) of water to produce about a 1:25,000 dilution. Skin stains may be removed with a weak solution of oxalic acid or sodium thiosulfate.

Definition

potassium permanganate: A compound,KMnO₄, forming purple crystalswith a metallic sheen, soluble inwater (intense purple solution), acetone,and methanol, but decomposedby ethanol; r.d. 2.70; decompositionbegins slightly above 100°C and iscomplete at 240°C. The compound isprepared by fusing manganese(IV)oxide with potassium hydroxide toform the manganate and electrolysingthe manganate solutionusing iron electrodes at about 60°C.An alternative route employs productionof sodium manganate by a similarfusion process, oxidation withchlorine and sulphuric acid, thentreatment with potassium chloride tocrystallize the required product.Potassium manganate(VII) is widelyused as an oxidizing agent and as adisinfectant in a variety of applications,and as an analytical reagent.

Preparation

Potassium permanganate is produced from manganese ore containing at least 60% manganese dioxide, MnO₂. The finely ground ore is mixed with 50%potassium hydroxide and heated at about 350°C in rotary kilns. This converts manganese dioxide to potassium manganate:
MnO₂2+ 4KOH + O₂→2K₂MnO₄+ 2H₂O
Potassium manganate obtained above is oxidized to the permanganate either by electrolysis or by chemical oxidation. Electrolytic oxidation is more common. Electrolytic cells have cathodes made of iron rods and nickel-plated anodes. Potassium manganate melt is extracted with water prior to its elec-trolysis and then electrolyzed at a cell voltage of 2.3V and current of about 1,400 amp. Permanganate is produced at theanode and water is reduced to gaseous hydrogen and hydroxyl ions at the cathode:
2K₂MnO₄4+ 2H₂O →2KMnO₄+ 2KOH + H₂.

General Description

A purplish colored crystalline solid. Noncombustible but accelerates the burning of combustible material. If the combustible material is finely divided the mixture may be explosive. Contact with liquid combustible materials may result in spontaneous ignition. Contact with sulfuric acid may cause fire or explosion. Used to make other chemicals and as a disinfectant.

Air & Water Reactions

Soluble in water.

Reactivity Profile

Potassium permanganate is a very powerful oxidizing agent, particularly in acidic surroundings. Reacts with incandescence with aluminum carbide [Mellor 5:872. 1946-47]. Grinding with antimony or arsenic causes ignition of the metals [Mellor 12:322. 1946-47]. Mixtures with acetic acid or acetic anhydride may explode if not kept cold [Von Schwartz 1918. p. 34]. Explosions can occur when acidified solutions come in contact with benzene, carbon disulfide, diethyl ether, ethyl alcohol, petroleum, or organic matter. Contact with glycerol may produce an explosion [Pieters 1957. p. 30]. Contact with concentrated hydrogen peroxide solution can produce an explosion [Haz. Chem. Data 1973. p. 230]. Contact with solid hydroxylamine produces an immediate white flame [Mellor 8:294. 1946-47]. Transport through a polypropylene tube ignited the tube [MCA Case History 1842. 1972]. Mixing with concentrated sulfuric acid in a vessel containing moisture caused an explosion (due to formation of manganese heptoxide) [Delhez 1967].

Hazard

Dangerous fire and explosion risk in contact with organic materials, powerful oxidizing agent.

Health Hazard

Burns and stains the skin dark brown. If ingested will cause severe distress of gastro-intestinal system. May be fatal if over 4 oz. are consumed.

Fire Hazard

Behavior in Fire: May cause fire on contact with combustibles. Containers may explode.

Flammability and Explosibility

Non flammable

reaction suitability

reagent type: oxidant

Industrial uses

This is a crystalline substance with a deep purple color, extremely soluble in water (60 g/L). At a temperature above 200 °C, KMnO4 decomposes according to the following reaction: 2KMnO4 +Heat K₂MnO₄ + MnO₂ + O₂
Potassium permanganate has a depressing effect on most sulfide minerals including sphalerite, pyrrhotite and chalcopyrite. It has been used to depress pyrrhotite and arsenopyrite in a pyrite flotation alkaline circuit. Studies were carried out on the depression of copper in copper–molybdenite separation with promising results. There is very little known about the depressing action of KMnO₄ in relation to pH.

Safety Profile

A human poison by ingestion. Poison experimentally by Flammable by chemical reaction. A powerful oxidizer. A dangerous explosion hazard; handle with care. Explosions may occur in contact with organic or readily oxidizable materials, either when dry or in solution. Dangerous; keep away from combustible materials. Explodes on contact with acetic acid, acetic anhydride, ammonium nitrate, dimethylformamide, formaldehyde, concentrated hydrochloric acid, potassium chloride + sulfuric acid, sulfuric acid + water. Forms sensitive explosive mixtures with aluminum powder + ammonium nitrate + glyceryl nitrate + nitrocellulose, ammonium perchlorate, arsenic, phosphorus, sulfur, slag wool, titanium. Ignites on contact with Aldi dimethyl sulfoxide, ethylene glycol, H2S3, HCl, H2SO4, (H2SO4 + organic matter), (H2SO4 + KCl), NH4ClO4, NH3, NH4, NO3, NH2OH, organic matter, wood, oxygenated organic compounds (e.g., ethylene glycol, propane-l,2-diol, erythritol, mannitol, triethanolamine, 3-chloropropane-l,2-diol, acetaldehyde, isobutyraldehyde, benzaldehyde, acetylacetone, esters of ethylene glycol, lactic acid, acetic acid, oxalic acid). proper condtions with acetone + tert- butylamine, alcohols + nitric acid, aluminum carbide, ammonia + sulfuric acid, antimony, coal + peroxomonosulfuric acid, dichloromethylsilane, dimethyl sulfoxide, ethanol + sulfuric acid, glycerol, concentrated hydrofluoric acid, hydrogen peroxide, hydrogen trisulfide, hydroxylamine, carbon, organic nitro compounds, polypropylene, 3,4,4'- trimethyldiphenyl sulfone. When heated to decomposition it emits toxic fumes of K2O. See also PERMAN GANATES.

Potential Exposure

Potassium permanganate is used in solutions as a disinfectant, topical antibacterial agent; deodorizer, bleaching agent; and in air and water purification.

Shipping

UN1490 Potassium permanganate, Hazard Class: 5.1; Labels: 5.1-Oxidizer.

Purification Methods

Crystallise it from hot water (4mL/g at 65o), then dry it in a vacuum desiccator over CaSO4. Phillips and Taylor [J Chem Soc 4242 1962] cooled an aqueous solution of KMnO4, saturated at 60o, to room temperature in the dark, and filtered it through a No.4 porosity sintered-glass filter funnel. The solution was allowed to evaporate in air in the dark for 12hours, and the supernatant liquid was decanted from the crystals, which were dried as quickly as possible with filter paper.

Incompatibilities

Potassium permanganate is a powerful oxidizing agent, that is, it will initiate a fire or explosion if brought into contact with reducing materials; combustibles, organic materials; strong acids; or oxidizable solid, liquid or gas; glycerin, ethylene glycol; polypropylene, hydroxyl- amine, hydrogen trisulfide; antimony, arsenic, sulfuric acid; hydrogen peroxide; phosphorus, and any finely divided combustible material. It will decompose, and release oxygen, if brought into contact with heat, alcohol, acids, ferrous salts; iodides and oxalates.

Toxics Screening Level

The initial threshold screening level (ITSL) for acute exposure to potassium permanganate (KMnO4) is 0.6 μg/m3 (8 hour averaging time) based on the Michigan Department of Environmental Quality (MDEQ), Air Quality Division (AQD) Rule 336.1232(1)(c).

Waste Disposal

React with reducing agent, neutralize and flush to sewer