performic acid

Performic acid is a colorless liquid soluble in water, alcohols, ether, benzene, chloroform and other organic solvents. Its strong oxidizing properties are used for cleaving disulfide bonds in protein mapping,{{cite journal|doi=10.1101/pdb.prot4698|last1=Simpson|year=2007|first1=R. J.|pages=pdb.prot4698|volume=2007|journal=Cold Spring Harbor Protocols|title=Performic Acid Oxidation of Proteins|issue=3 }} as well as for epoxidation, hydroxylation{{cite journal |title=trans-1,2-CYCLOHEXANEDIOL |journal=Organic Syntheses |date=1948 |volume=28 |pages=35 |doi=10.15227/orgsyn.028.0035}} and oxidation reactions in organic synthesis.Pradyot Patnaik [https://books.google.com/books?id=-CRRJBVv5d0C&pg=PA128 A comprehensive guide to the hazardous properties of chemical substances], Wiley-Interscience, 2007, {{ISBN|0-471-71458-5}}, p. 128 In the medical and food industries, performic acid is commonly used to disinfect equipment. It is effective against viruses, bacterial spores, algae, microscopic fungi and mycobacteria, as well as other microorganisms such as zooplankton.

The popularity of performic acid as a sterilizer originates from the safe nature of its degradation products, mostly carbon dioxide, oxygen and water.{{cite journal|last1=Gehr|first1=R|last2=Chen|first2=D|last3=Moreau|first3=M|title=Performic acid (PFA): tests on an advanced primary effluent show promising disinfection performance|url=http://www.iwaponline.com/wst/05901/0089/059010089.pdf|journal=Water Science and Technology|volume=59|issue=1|pages=89–96|year=2009|pmid=19151490|doi=10.2166/wst.2009.761|url-status=dead|archiveurl=https://web.archive.org/web/20101116222519/http://www.iwaponline.com/wst/05901/0089/059010089.pdf|archivedate=2010-11-16}} The disinfecting action of performic acid is also faster than that of the related compounds peracetic acid and hydrogen peroxide. The major drawbacks of performic acid are handling dangers related to its high reactivity, as well as instability, especially upon heating, which means that the acid must be used within about 12 hours of it being synthesised.{{cite journal|author1=Bydzovska, O. |author2=Merka, V. |name-list-style=amp |year=1981 |title=Disinfecting Properties of Performic Acid Against Bacteriophage (X 174 as a Model of Small Envelope-free Viruses|pmid=6459365|journal=J. Hygiene, Epidemiology Microbiology and Immunology |volume=25|issue=4|pages=414–423}}{{cite journal|title=Execution of a Performic Acid Oxidation on Multikilogram Scale|doi=10.1021/op700039r|author= Ripin, D.H.B.|year=2007|pages=762–765|volume=11|journal=Org. Process Res. Dev.|issue=4 |display-authors=etal}}

Performic acid is synthesized by the reaction of formic acid and hydrogen peroxide by the following equilibrium reaction:

File:Performic acid Synthesis V2.svg

Synthesis of pure performic acid has not been reported, but aqueous solutions up to about 48% can be formed by simply mixing equimolar amounts of concentrated aqueous reactant solutions. Using an excess of either reactant shifts the equilibrium towards the product side. The aqueous product solution can be distilled to increase the concentration of performic acid to about 90%.

This reaction is reversible and can be used for large scale industrial production if accelerated with a catalyst; however, its temperature must be kept below 80–85 °C to avoid an explosion.Elvers, B. et al. (ed.) (1991) Ullmann's Encyclopedia of Industrial Chemistry, 5th ed. Vol. A12, Wiley, p. 16 The catalyst can be nitric, hydrofluoric, phosphoric or sulfuric acid or their salts;{{cite journal|last1=Swern|first1=Daniel|title=Organic Peracids.|journal=Chemical Reviews|volume=45|pages=1–68|year=1949|doi=10.1021/cr60140a001|quote=In the absence of catalysts, performic acid explodes when heated rapidly to 80–85°C.}}{{cite journal|doi=10.1021/ja01201a016|last1=English|first1=James|year=1947|pages=2120|volume=69|journal=Journal of the American Chemical Society|last2=Gregory|first2=J. Delafield|title=Performic Acid Hydroxylation of a,p-Unsaturated Acids and Esters}} it can also be an organic compound containing at least one ester group, such as carboxylic acid esterMatilla, T. and Aksela, R. 2000 Method for the Preparation of Aqueous Solutions Containing Performic Acid as Well as Their Use. {{US Patent|6049002}}, Issue date: April 11, 2000 or peracetic acid.Preuss, A., Fuchs, R., Huss, M. & Schneider, R. 2001 Aqueous Disinfecting Agent Containing Performic Acid and Peracetic Acid Process for Production and Process for Use Thereof {{US Patent|6211237}}, Issue date: April 3, 2001

Performic acid is non-toxic; it does irritate the skin, but less so than peracetic acid. Concentrated acid (above 50%) is highly reactive; it readily decomposes upon heating, and explodes upon rapid heating to 80–85 °C. It may ignite or explode at room temperature when combined with flammable substances, such as formaldehyde, benzaldehyde, or aniline, and explodes violently upon addition of metal powders. For this reason, spilled performic acid is diluted with cold water and collected with neutral, non-flammable inorganic absorbents, such as vermiculite.

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Category:Organic peroxy acids