Potassium permanganate

Potassium permanganate is an inorganic compound with the chemical formula KMnO₄. It is a purplish-black crystalline salt, that dissolves in water as K⁺ and MnO⁻
₄, an intensely pink to purple solution.

Potassium permanganate

Names
IUPAC name Potassium manganate(VII)
Systematic IUPAC name Potassium permanganate
Other names Chameleon mineral Condy's crystals Permanganate of potash Hypermangan Purple potion powder
Identifiers
CAS Number	7722-64-7^Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL3833305
ChemSpider	22810
DrugBank	DB13831
ECHA InfoCard	100.028.874
EC Number	231-760-3
KEGG	D02053^Y
PubChem CID	516875
RTECS number	SD6475000
UNII	00OT1QX5U4
UN number	1490
CompTox Dashboard (EPA)	DTXSID2034839
InChI InChI=1S/K.Mn.4O/q+1;;;;;-1^Y Key: VZJVWSHVAAUDKD-UHFFFAOYSA-N^Y
SMILES [K+].[O-] [Mn](=O)(=O)=O
Properties
Chemical formula	KMnO4
Molar mass	158.034 g/mol
Appearance	Purplish-bronze-gray needles purple in solution^[1]
Odor	odorless
Density	2.7 g/cm^3^[2]^: 4.83
Melting point	240 °C (464 °F; 513 K) (decomposes)
Solubility in water	76 g/L (25 °C)^[2] 250 g/L (65 °C)
Solubility	decomposes in alcohol and organic solvents
Magnetic susceptibility (χ)	+20.0·10^−6 cm^3/mol^[2]^: 4.134
Refractive index (nD)	1.59
Structure^[3]
Crystal structure	Orthorhombic, oP24
Space group	Pnma, No. 62
Lattice constant	a = 0.909 nm, b = 0.572 nm, c = 0.741 nm
Formula units (Z)	4
Thermochemistry
Heat capacity (C)	119.2 J/mol K
Std molar entropy (S^⦵298)	171.7 J K^−1 mol^−1
Std enthalpy of formation (ΔfH^⦵298)	−813.4 kJ/mol
Gibbs free energy (ΔfG^⦵)	-713.8 kJ/mol
Pharmacology
ATC code	D08AX06 (WHO) V03AB18 (WHO)
Hazards
GHS labelling:
Pictograms
NFPA 704 (fire diamond)	2 0 1 OX
Lethal dose or concentration (LD, LC):
LD50 (median dose)	1090 mg/kg (oral, rat)^[4]
Related compounds
Other anions	Potassium pertechnetate Potassium perrhenate
Other cations	Sodium permanganate Ammonium permanganate Calcium permanganate Silver permanganate
Related manganates	Potassium hypomanganate Potassium manganate
Related compounds	Manganese heptoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Potassium permanganate

Clinical data
License data	US DailyMed: Potassium_permanganate
Identifiers
CompTox Dashboard (EPA)	DTXSID2034839
ECHA InfoCard	100.028.874

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.^[5] In 2000, worldwide production was estimated at 30,000 tons.^[5]

Properties

Potassium permanganate is the potassium salt of the tetrahedral transition metal oxo complex permanganate, in which four O²⁻ ligands are bound to a manganese(VII) center.^{[citation needed]}

Structure

KMnO₄ forms orthorhombic crystals with constants: a = 910.5 pm, b = 572.0 pm, c = 742.5 pm. The overall motif is similar to that for barium sulfate, with which it forms solid solutions.^[6] In the solid (as in solution), each MnO−4 centre is tetrahedral. The Mn–O distances are 1.62 Å.^[7]

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.^[8]

Uses

Almost all applications of potassium permanganate exploit its oxidizing properties.^[9] As a strong oxidant that does not generate toxic byproducts, KMnO₄ has many niche uses.^{[citation needed]}

Medical uses

Main article: Potassium permanganate (medical 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 tropical ulcers.^[11][10] It is on the World Health Organization's List of Essential Medicines.^[5]

Water treatment

Potassium permanganate is used extensively in the water treatment industry. It is used as a regeneration chemical to remove iron and hydrogen sulfide (rotten egg smell) from well water via a "manganese greensand" filter. "Pot-Perm" is also obtainable at pool supply stores and is used additionally to treat wastewater. Historically it was used to disinfect drinking water^[12][13] and can turn the water pink.^[14] Modern hiking and survivalist guides advise against using potassium permanganate in the field because it is difficult to dose correctly.^[15] It currently finds application in the control of nuisance organisms such as zebra mussels in fresh water collection and treatment systems.^[16]

Synthesis of organic compounds

 

A solution of KMnO₄ in water, in a volumetric flask

A major application of KMnO₄ is as a reagent for the synthesis of organic compounds.^[17] Significant amounts are required for the synthesis of ascorbic acid, chloramphenicol, saccharin, isonicotinic acid, and pyrazinoic acid.^[9]

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 (-C=C- or -C≡C-) causes the color to fade from purplish-pink to brown. Aldehydes and formic acid (and formates) also give a positive test.^[18] The test is antiquated.

 

Baeyer's reagent reaction

KMnO₄ solution is a common thin layer chromatography stain for the detection of oxidizable functional groups, such as alcohols, aldehydes, alkenes, and ketones. Such compounds result in a white to orange spot on TLC plates.^[19][20][21]

Analytical use

Potassium permanganate can be used to quantitatively determine the total oxidizable organic material in an aqueous sample. The value determined is known as the permanganate value. In analytical chemistry, a standardized aqueous solution of KMnO₄ is sometimes used as an oxidizing titrant for redox titrations (permanganometry). As potassium permanganate is titrated, the solution becomes a light shade of purple, which darkens as excess of the titrant is added to the solution. In a related way, it is used as a reagent to determine the Kappa number of wood pulp. For the standardization of KMnO₄ solutions, reduction by oxalic acid is often used.^[22] In agricultural chemistry, it is used for estimation of active carbon in soil.^[23]

Aqueous, acidic solutions of KMnO₄ are used to collect gaseous mercury in flue gas during stationary source emissions testing.^[24]

In histology, potassium permanganate was used as a bleaching agent.^[25][26]

Fruit preservation

Ethylene absorbents extend storage time of bananas even at high temperatures. This effect can be exploited by packing bananas in polyethylene together with potassium permanganate. By removing ethylene by oxidation, the permanganate delays the ripening, increasing the fruit's shelf life up to 4 weeks without the need for refrigeration.^[27][28][29]

Survival kits

Potassium permanganate is sometimes included in survival kits: as a hypergolic fire starter (when mixed with glycerol antifreeze from a car radiator);^[30][31][32] as a water sterilizer; and for creating distress signals on snow.^[33]

Fire service

Potassium permanganate is added to "plastic sphere dispensers" to create backfires, burnouts, and controlled burns. Polymer spheres resembling ping-pong balls containing small amounts of permanganate are injected with ethylene glycol and projected towards the area where ignition is desired, where they spontaneously ignite seconds later.^[34][35] Both handheld^[35] helicopter-^[34] unmanned aircraft systems (UAS) or boat-mounted^[35] plastic sphere dispensers are used.

Other uses

Potassium permanganate is one of the principal chemicals used in the film and television industries to "age" props and set dressings. Its ready conversion to brown MnO₂ creates "hundred-year-old" or "ancient" looks on hessian cloth (burlap), ropes, timber, and glass.^[36]

Potassium permanganate can be used to oxidize cocaine paste to purify it and increase its stability. This led to the Drug Enforcement Administration launching Operation Purple in 2000, with the goal of monitoring the world supply of potassium permanganate; however, potassium permanganate derivatives and substitutes were soon used thereafter to avoid the operation.^[37]

Potassium permangate is used as an oxidizing agent in the synthesis of cocaine and methcathinone.^[38]

Potassium permanganate is one of a number of possible treatments for Ichthyophthirius multifiliis (commonly known as "ich"), a parasite that infects and usually kills freshwater aquarium fish.

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.^[39] 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". This report represents the first description of the production of potassium permanganate.^[40] 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.^[41]

Early photographers used it as a component of flash powder. It is now replaced with other oxidizers, due to the instability of permanganate mixtures.^{[citation needed]}

Preparation

Potassium permanganate is produced industrially from manganese dioxide, which also occurs as the mineral pyrolusite. In 2000, worldwide production was estimated at 30,000 tonnes.^[9] The MnO₂ is fused with potassium hydroxide and heated in air or with another source of oxygen, like potassium nitrate or potassium chlorate.^[9] This process gives potassium manganate:

${\displaystyle {\ce {2 MnO2 + 4 KOH + O2 -> 2 K2MnO4 + 2 H2O}}}$ 

(With sodium hydroxide, the end product is not sodium manganate but an Mn(V) compound, which is one reason why the potassium permanganate is more commonly used than sodium permanganate. Furthermore, the potassium salt crystallizes better.^[9])

The potassium manganate is then converted into permanganate by electrolytic oxidation in alkaline media:

${\displaystyle {\ce {2 K2MnO4 + 2 H2O -> 2 KMnO4 + 2 KOH + H2}}}$ 

Other methods

Although of no commercial importance, potassium manganate can be oxidized by chlorine or by disproportionation under acidic conditions.^[42] The chlorine oxidation reaction is

${\displaystyle {\ce {2 K2MnO4 + Cl2 -> 2 KMnO4 + 2 KCl}}}$ 

and the acid-induced disproportionation reaction may be written as

${\displaystyle {\ce {3 K2MnO4 + 4 HCl -> 2 KMnO4 + MnO2 + 2 H2O + 4 KCl}}}$ 

A weak acid such as carbonic acid is sufficient for this reaction:

${\displaystyle {\ce {3 K2MnO4 + 2 CO2 -> 2 KMnO4 + 2 K2CO3 + MnO2}}}$ 

Permanganate salts may also be generated by treating a solution of Mn²⁺ ions with strong oxidants such as lead dioxide (PbO₂), sodium bismuthate (NaBiO₃), or peroxydisulfate. Tests for the presence of manganese exploit the vivid violet color of permanganate produced by these reagents.

Reactions

Organic chemistry

Dilute solutions of KMnO₄ convert alkenes into diols. This behaviour is also used as a qualitative test for the presence of double or triple bonds in a molecule, since the reaction decolorizes the initially purple permanganate solution and generates a brown precipitate (MnO₂). In this context, it is sometimes called Baeyer's reagent. However, bromine serves better in measuring unsaturation (double or triple bonds) quantitatively, since KMnO₄, being a very strong oxidizing agent, can react with a variety of groups.

Under acidic conditions, the alkene double bond is cleaved to give the appropriate carboxylic acid:^[43]

${\displaystyle {\ce {CH3(CH2)17CH=CH2 + 2 KMnO4 + 3 H2SO4 -> CH3(CH2)17COOH + CO2 + 4 H2O + K2SO4 + 2 MnSO4}}}$ 

Potassium permanganate oxidizes aldehydes to carboxylic acids, illustrated by the conversion of n-heptanal to heptanoic acid:^[44]

${\displaystyle {\ce {5 C6H13CHO + 2 KMnO4 + 3 H2SO4 -> 5 C6H13COOH + 3 H2O + K2SO4 + 2 MnSO4}}}$ 

Even an alkyl group (with a benzylic hydrogen) on an aromatic ring is oxidized, e.g. toluene to benzoic acid.^[45]

${\displaystyle {\ce {5 C6H5CH3 + 6 KMnO4 + 9 H2SO4 -> 5 C6H5COOH + 14 H2O + 3 K2SO4 + 6 MnSO4}}}$ 

Glycols and polyols are highly reactive toward KMnO₄. For example, addition of potassium permanganate to an aqueous solution of sugar and sodium hydroxide produces the chemical chameleon reaction, which involves dramatic color changes associated with the various oxidation states of manganese. A related vigorous reaction is exploited as a fire starter in survival kits. For example, a mixture of potassium permanganate and glycerol or pulverized glucose ignites readily.^[30] Its sterilizing properties are another reason for inclusion of KMnO₄ in a survival kit.^{[citation needed]}

Ion exchange

Treating a mixture of aqueous potassium permanganate with a quaternary ammonium salt results in ion exchange, precipitating the quat salt of permanganate. Solutions of these salts are sometimes soluble in organic solvents:^[46]

${\displaystyle {\ce {KMnO4 + R4NCl -> R4NMnO4 + KCl}}}$ 

Similarly, addition of a crown ether also gives a lipophilic salt.^[47]

Reaction with acids and bases

Permanganate reacts with concentrated hydrochloric acid to give chlorine and manganese(II):

${\displaystyle {\ce {2 KMnO4 + 16 HCl -> 2 MnCl2 + 5 Cl2 + 2 KCl + 8 H2O}}}$ 

In neutral solution, permanganate slowly reduces to manganese dioxide (MnO₂). This is the material that stains one's skin when handling KMnO₄.

KMnO₄ reduces in alkaline solution to give green K₂MnO₄:^[48]

${\displaystyle {\ce {4 KMnO4 + 4 KOH -> 4 K2MnO4 + O2 + 2 H2O}}}$ 

This reaction illustrates the relatively rare role of hydroxide as a reducing agent.

Addition of concentrated sulfuric acid to potassium permanganate gives Mn₂O₇.^[49] Although no reaction may be apparent, the vapor over the mixture will ignite paper impregnated with alcohol. Potassium permanganate and sulfuric acid react to produce some ozone, which has a high oxidizing power and rapidly oxidizes the alcohol, causing it to combust. As the reaction also produces explosive Mn₂O₇, this should only be attempted with great caution.^[50][51]

Thermal decomposition

Solid potassium permanganate decomposes when heated:

${\displaystyle {\ce {2 KMnO4 -> K2MnO4 + MnO2 + O2}}}$ 

Safety and handling

Potassium permanganate poses risks as an oxidizer.^[52] Contact with skin will result in a long lasting brown stain.^[53]

References

1. Burriel F, Lucena F, Arribas S, Hernández J (1985). Química Analítica Cualitativa [Qualitative Analytical Chemistry] (in Spanish). p. 688. ISBN 84-9732-140-5.
2. Haynes WM, ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). CRC Press. ISBN 978-1439855119.
3. Hocart R, Mathieu-Sicaud A (1945). "A stabilization factor in the polymorphism of ammonium nitrate". Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences [Weekly Reports of the Sessions of the Academy of Sciences] (in French). 221: 261–263.
4. Chambers M. "Potassium permanganate [USP:JAN] – Similar structures search, synonyms, formulas, resource links, and other chemical information". ChemIDplus: A Toxnet database. U.S. National Library of Medicine. ChemIDplus – CAS: 7722-64-7 InChi: VZJVWSHVAAUDKD-UHFFFAOYSA-N. Archived from the original on 13 August 2014. Retrieved 9 May 2018.
5. World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
6. Brauer E, ed. (1963). Handbook of Preparative Inorganic Chemistry. New York: Academic Press.
7. Palenik GJ (1967). "Crystal structure of potassium permanganate". Inorg. Chem. 6 (3): 503–507. doi:10.1021/ic50049a015.
8. Miessler GL, Fischer PJ, Tarr DA (2014). Inorganic Chemistry (5th ed.). Pearson. p. 430. ISBN 978-0321811059.
9. Reidies AH (2002). "Manganese Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_123.
10. World Health Organization (2009). Stuart MC, Kouimtzi M, Hill SR (eds.). WHO Model Formulary 2008. World Health Organization. pp. 295, 300. hdl:10665/44053. ISBN 9789241547659.
11. British Medical Association; Royal Pharmaceutical Society (2015). British national formulary (69 ed.). p. 840. ISBN 9780857111562.
12. Assembly of Life Sciences (U.S.). Safe Drinking Water Committee (1977). Drinking water and health, Volume 2. National Academies Press. p. 98. ISBN 978-0-309-02931-5. Retrieved 2016-09-13.
13. Downey R, Barrington M (28 February 2005). . The Northern Advocate. Archived from the original on 2011-07-19.
14. "Onoway apologizes for 'alarming' pink tap water". CBC News. 7 March 2017. from the original on 7 March 2017. Retrieved 8 March 2017.
15. Johannes Vogel. Trinkwasserversorgung in Extremsituationen (in German). Paul Pietsch Verlage GmbH. ISBN 978-3613507845.
16. . U.S. Environmental Protection Agency. 13 October 2015. Archived from the original on 2016-10-01.
17. Fatiadi A (1987). "The Classical Permanganate Ion: Still a Novel Oxidant in Organic Chemistry". Synthesis. 1987 (2): 85–127. doi:10.1055/s-1987-27859.
18. Glagovich N (2013). . Department of Chemistry and Biochemistry. Central Connecticut State University. Archived from the original on 24 January 2013. Retrieved 9 May 2018.
19. Thin Layer Chromatography stains http://www.reachdevices.com/TLC_stains.html
20. Jork, H., Funk, W., Fischer, W., Wimmer, H. (1990): Thin-Layer Chromatography: Reagents and Detection Methods, Volume 1a, VCH, Weinheim, ISBN 3-527-278834
21. Jork, H., Funk, W., Fischer, W., Wimmer, H. (1994): Thin-Layer Chromatography: Reagents and Detection Methods, Volume 1b, VCH, Weinheim
22. Kovacs KA, Grof P, Burai L, Riedel M (2004). "Revising the Mechanism of the Permanganate/Oxalate Reaction". J. Phys. Chem. A. 108 (50): 11026. Bibcode:2004JPCA..10811026K. doi:10.1021/jp047061u.
23. "Quick Reference Guide: Potassium Permanganate Test for Active Carbon". Agriculture Victoria—Victorian Resources Online. Victoria, Australia.
24. Code of Federal Regulations(7-1-07) Edition, Title 40, Part 60, Appendix A-8, Method 29, Section 7.3.1
25. Picken MM (April 2010). "Amyloidosis-where are we now and where are we heading?". Archives of Pathology & Laboratory Medicine. 134 (4): 545–551. doi:10.5858/134.4.545. PMID 20367306.
26. Murphy CL, Eulitz M, Hrncic R, Sletten K, Westermark P, Williams T, Macy SD, Wooliver C, Wall J, Weiss DT, Solomon A (July 2001). "Chemical typing of amyloid protein contained in formalin-fixed paraffin-embedded biopsy specimens". American Journal of Clinical Pathology. 116 (1): 135–142. doi:10.1309/TWBM-8L4E-VK22-FRH5. PMID 11447744.
27. Scott KJ, McGlasson WB, Roberts EA (1970). "Potassium Permanganate as an Ethylene Absorbent in Polyethylene Bags to Delay the Ripening of Bananas During Storage". Australian Journal of Experimental Agriculture and Animal Husbandry. 10 (43): 237. doi:10.1071/EA9700237.
28. Scott KJ, Blake, JR, Stracha, G, Tugwell, BL and McGlasson WB (1971). "Transport of Bananas at Ambient Temperatures using Polyethylene Bags". Tropical Agriculture (Trinidad). 48: 163–165.
29. Scott KJ, Gandanegara S (1974). "Effect of Temperature on the Storage Life of bananas Held in Polyethylene Bags with an Ethylene Absorbent". Tropical Agriculture (Trinidad). 51: 23–26.
30. Gillis B, Labiste D. "Fire by Chemical Reaction". PrimitiveWays. from the original on 2015-09-24.
31. (PDF). Pole Shift Survival Information. Archived from the original (PDF) on 4 August 2016. Retrieved 9 May 2018.
32. "Making Fire with Potassium Permanganate and Glycerin". thesurvivalcache. 3 November 2012. from the original on 13 May 2016. Retrieved 13 September 2016.
33. "Distress Signals". Evening Post. CXXI (107): 5. 7 May 1936. from the original on 5 November 2011.
34. . Missoula Technology and Development Center. USDA Forest Service. Archived from the original on 26 April 2016. Retrieved 9 May 2018.
35. "Wetland Warrior". Dirty Jobs. Season 6. Episode 2.
36. Brody E (February 2000). "Victor DeLor contractor profile". PaintPRO. 2 (1). from the original on 2008-07-23. Retrieved 2009-11-12. One of the techniques DeLor is known for among designers and clients is the special effects he creates with various chemical solutions. When applied to wood surfaces, these chemicals give a weathered appearance to new wood. ... To achieve the aesthetic on interior surfaces, DeLor often uses a mixture of water and potassium permanganate, a dry powder chemical.
37. Gosmer K, Vammen M (March 10, 2014). "The Terrifying Substances People Put in Cocaine". Vice Media.
38. Binder R, Machata G, Stead H (May 2003). "[Analysis of potassium permanganate as addictive drug "precursor"]". Archiv Fur Kriminologie. 211 (5–6): 160–165. PMID 12872685.
39. Glauber, Johann Rudolph, Prosperitas Germaniae (The prosperity of Germany), part 3 (Amsterdam, (Netherlands): Johann Jansson, 1659), pp. 93–94. From pp. 93–94: " … donec tandem Magnesiam istam nitro fixo permixtam, in crucibulo forti coctione a nitro reseratam vidi, unde elegans color purpureus provenit, massam hanc effusam in pulvere redegi, aqua calida extraxi, per filtrum liquorem transmisi. Tandem vero elegantissimum purpureum, igneumque liquorem accepi, qui fere singulis horis in frigore tantummodo consistens colorem permutavit, sic ut jam viridis, jam caerulei, jam sanguinei coloris sponte sua factus sit, mox iterum alios elegantissimos colores receperit." ( … until finally I saw [that] by mixing that magnesia [i.e., magnesia nigra, pyrolusite, the ore containing manganese dioxide ] with fixed niter [i.e., inert niter, potassium carbonate], by cooking [it] in a strong crucible, [the colored compound was] released by the niter, whence a fine purple color arises; this mass [was] poured out, reduced to powder, extracted with hot water, [and] the solution passed through a filter. Then I got a truly most elegant, purple, and fiery solution, which nearly every hour ([while] standing just in the cold) changed color, so that it was spontaneously made now green, now blue, now red in color; soon again it received other most elegant colors.) Glauber JR. [Part of the Prosperity of Germany .... 3: In which the method of extracting saltpeter from various everywhere, in the most convenient and abundant manner, is given. His interests are clearly stated] (in Latin). Archived from the original on 2016-12-20 – via Bavarian State Library. Translated in: Glauber JR (1689). . Translated by Packe C. London, England: Thomas Millbourn. p. 353. Archived from the original on 2012-01-07.
40. Weeks ME (1956). Leicester HM (ed.). Discovery of the Elements (6th ed.). Easton, Pennsylvania: Journal of Chemical Education. pp. 172–173.
41. "Important Trade Mark Case". Otago Witness. 2 (2420): 53. 2 August 1900. from the original on 4 March 2016.
42. Walton HF (1948). Inorganic Preparations. New York: Prentice-Hall. pp. 150–151.
43. Lee DG, Lamb SE, Chang VS (1990). "Carboxylic Acids from the Oxidation of Terminal Alkenes by Permanganate: Nonadecanoic Acid". Organic Syntheses.; Collective Volume, vol. 7, p. 397
44. Ruhoff JR. "n-Heptanoic acid". Organic Syntheses.; Collective Volume, vol. 2, p. 315
45. Gardner KA, Mayer JM (September 1995). "Understanding C-H bond oxidations: H. and H- transfer in the oxidation of toluene by permanganate". Science. 269 (5232): 1849–1851. Bibcode:1995Sci...269.1849G. doi:10.1126/science.7569922. PMID 7569922.
46. Herriott AW (1977). "Purple benzene: Solubilization of anions in organic solvents". J. Chem. Educ. 54 (4): 229. Bibcode:1977JChEd..54Q.229H. doi:10.1021/ed054p229.1.
47. Doheny Jr AJ, Ganem B (1980). "Purple benzene revisited". J. Chem. Educ. 57 (4): 308. Bibcode:1980JChEd..57..308D. doi:10.1021/ed057p308.1.
48. Nyholm RS, Woolliams PR (1968). "Manganates(VI)". Inorganic Syntheses. pp. 56–61. doi:10.1002/9780470132425.ch11. ISBN 978-0-470-13242-5. {{cite book}}: |journal= ignored (help)
49. Cotton FA, Wilkinson G, Murillo CA, Bochmann M (1999). Advanced Inorganic Chemistry (6th ed.). Wiley-VCH. ISBN 0-471-19957-5.
50. Barthel H, Duvinage B (2000). "Clemens Winkler. His Experiments with Ozone in 1892". Praxis der Naturwissenschaften, Chemie. 49: 18ff.
51. Dzhabiev TS, Denisov NN, Moiseev DN, Shilov AE (2005). "Formation of Ozone During the Reduction of Potassium Permanganate in Sulfuric Acid Solutions". Russian Journal of Physical Chemistry. 79: 1755–1760.
52. Bretherick L, Urben PG, Pitt MJ (2007). Bretherick's Handbook of Reactive Chemical Hazards. Vol. 1 (7th ed.). Elsevier Academic Press. pp. 1811–7. ISBN 978-0-12-373945-2.
53. Griffin S. "How to Remove Potassium Permanganate". livestrong.com. from the original on 13 April 2018. Retrieved 9 May 2018.

Further reading

• "Potassium permanganate". Drug Information Portal. U.S. National Library of Medicine.
• "Manganese and compounds Fact Sheet". National Pollutant Inventory. Australia: Department of Climate Change, Energy, the Environment and Water.
• Lazur AM (2009). . IFAS Extention. Gainesville, FL: University of Florida. Archived from the original on 2011-06-06.

External links

• International Chemical Safety Card 0672