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Pentachloronitrobenzene was originally synthesized in a laboratory in 1868. It was introduced to the agricultural world in the 1930s in Germany by Bayer AG as a substitute to mercurial pesticides. Pentachloronitrobenzene is prepared by chlorination of nitrobenzene at 60 – 70 ◦C in chlorosulfuric acid, with iodine as a catalyst. It can also be produced by the nitration of chlorinated benzenes.1 A side product of the synthesis of PCNB is hexachlorobenzene (HCB), which is considered equally as hazardous as PCNB{{cite journal | journal = J. Agric Food Chem. | year = 1987 | pages = 433-439 | doi = 10.1021/jf00075a037 |title = Identification of Several New Metabolites from Pentachloronitrobenzene by Gas Chromotagraphy/Mass Spectrometry | author = Cairns et. al}}

:1. 5 Cl₂ + C₂H₅NO₂ → C₆Cl₅NO₂ + 5 HCl

Reaction with ethanol – potassium hydroxide yields pentachlorophenetole, exemplifying

an easy route to pentachlorophenyl ethers.Booth, G. Nitro Compunds, Aromatic, Ullmann's Encyclopedia of Industrial Chemistry, electronic release 7th ed.; Wiley-VCH,Weinheim, 2000. {{ISBN|978-3-527-31965-7}}

:2. C₆Cl₅NO₂ + KOCH₂CCH₃ → C₆Cl₅OCH₂CH₃ + KNO₂

Although PCNB has a very stable shelf life, it is labile in soil, with a half life of 1.8 days. It degrades to other metabolites, mainly reducing to pentachloroaniline (PCA), but also to pentachlorophenol (PCP) through hydrolysis and pentachlorothioanisole (PCTA). There is little information known about the degradation mechanisms.{{cite journal | journal = The Journal of Microbiology | year = 2003 | pages = 165-168 | doi = | title = Isolation and Identification of a Pentachloronitrobenzene(PCNB) Degrading bacterium Alcaligenes xylosoxidans PCNB-2 from Agricultural Soil | author = Sung-Kyu Shin et. al}}{{cite journal | journal = Anal. Sci | year = 2006 | pages = 293 | issn= 0910-6340 | title = Determination of 17 kinds of Banned Organochlorine Pestides in Water by Activated Carbon Fiber-Solid Phase Microextraction Coupled with GC-MS | author = Tonghua Sun et. al}}

:3. C₆Cl₅NO₂ + 6 [H] → C₆Cl₅NH₂ + 2 H₂O

:4. C₆Cl₅NO₂ + 6 H₂O → C₆Cl₅OH + HNO₂

PCNB is used as a fungicide to suppress the growth of fungi in various crops, such as cotton, rice, and seed grains. It is also used to prevent the formation of slime in industrial waters. In 1989, usage of the compound was banned in the United States because of its persistence in the environment. In April 1993, PCNB became a federal hazardous air pollutant and was identified as a toxic air contaminant.Howard, P. H. Handbook of Environmental Fate and Exposure Data for Organic Chemicals: Pesticides , CRC Press, 1991; pp. 551-553. {{ISBN|0873713281}}, 9780873713283 PCNB is still used widely in other countries as a fungicide, such as China and Japan. Residual amounts of the compound and its metabolites are still found in crops today. The degradation products, PCA and PCTA have been found in farming soils and in river sediments.Sullivan, J. B.; Krieger, G. R. Clinical Environmental Health and Toxic Exposures, 2nd ed.; Lippincott Williams & Wilkins: Philadelphia, PA, 2001; pp. 1111-1112. {{ISBN|068308027X}}, 9780683080278