1,4-Dichlorobenzene 1826047 221793686 2008-06-26T03:26:47Z SmackBot 433328 Date the maintenance tags or general fixes {{Chembox new | Name = 1,4-Dichlorobenzene | ImageFileL1 = 1,4-Dichlorobenzene.svg | ImageSizeL1 = 120px | ImageNameL1 = 1,4-Dichlorobenzene | ImageFileR1 = Para-dichlorobenzene-3D-balls.png | ImageSizeR1 = 100px | ImageNameR1 = Ball-and-stick model of 1,4-dichlorobenzene | IUPACName = 1,4-Dichlorobenzene | OtherNames = ''para''-Dichlorobenzene<br />''p''-Dichlorobenzene<br />p-DCB<br/>PDB<br/>Paramoth<br/>Para crystals<br/>Paracide | Section1 = {{Chembox Identifiers | SMILES = ClC1=CC=C(Cl)C=C1 | CASNo = 106-46-7 | RTECS = CZ4550000 }} | Section2 = {{Chembox Properties | Formula = C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub> | MolarMass = 147.00 g/mol | Density = 1.25 g/cm³, solid | Solubility = 10.5 mg/100 ml (20 °C) | MeltingPt = 53.5 °C | BoilingPt = 174 °C }} | Section7 = {{Chembox Hazards | EUClass = Harmful ('''Xn''')<br />[[Carcinogen|Carc. Cat. 3]]<br />Dangerous for<br />the environment ('''N''') | NFPA-H = 2 | NFPA-F = 2 | NFPA-R = | RPhrases = {{R36}}, {{R40}}, {{R50/53}} | SPhrases = {{S2}}, {{S36/37}}, {{S46}},<br />{{S60}}, {{S61}} | FlashPt = 66 °C }} | Section8 = {{Chembox Related | OtherCpds = [[1,2-Dichlorobenzene]]<br />[[1,3-Dichlorobenzene]] }} }} '''1,4-Dichlorobenzene''' (''para''-dichlorobenzene, p-DCB, PDB) is an [[organic compound]] with the [[chemical formula|formula]] C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub>. This colourless [[solid]] has an [[odor]] akin to that of [[camphor]]. It consists of two [[chlorine]] atoms substituted at opposing sites on a [[benzene]] ring. ''p''-DCB is used a pesticide and a deodorant, most famously in [[mothball]]s in which it is a replacement for the more traditional [[naphthalene]]. ''p''-DCB is also used as a precursor in the production of the polymer [[poly(p-phenylene sulfide)]].<ref name=Ross>Manfred Rossberg, Wilhelm Lendle, Gerhard Pfleiderer, Adolf Tögel, Eberhard-Ludwig Dreher, Ernst Langer, Heinz Rassaerts, Peter Kleinschmidt, Heinz Strack, Richard Cook, Uwe Beck, Karl-August Lipper, Theodore R. Torkelson, Eckhard Löser, Klaus K. Beutel, “Chlorinated Hydrocarbons” in Ullmann’s Encyclopedia of Industrial Chemistry, 2006 John Wiley-VCH: Weinheim.DOI: 10.1002/14356007.a06_233.pub2</ref> ==Production== ''p''-DCB is produced by [[chlorination]] of benzene using [[ferric chloride]] as a catalyst: :C<sub>6</sub>H<sub>6</sub> + 2 Cl<sub>2</sub> → C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub> + 2 [[hydrogen chloride|HCl]] The chief impurity is the 1,2 isomer. The compound can be purified by fractional crystallization, taking advantage of its relatively high melting point of 54.5 °C; the isomeric dichlorobenzenes and chlorobenzene melt well below room temperature.<ref name=Ross/> ==Uses== ==== Disinfectant, deodorant, and pesticide==== ''p''-DCB is used to control [[moth]]s, [[mould]]s, and [[mildew]]. It finds use as a disinfectant{{Fact|date=June 2008}} in waste containers and restrooms and is the characteristic smell associated with [[urinal cake]]s. Its usefulness in these arises from ''p''-DCB's low solubility in water and its relatively high volatility: it [[sublimation (chemistry)|sublimes]] readily near room temperature.<ref name=Ross/> ====Precursor to other chemicals==== The chlorides on ''p''-DCB can be [[nucleophilic substitution|substituted]] with oxygen, amine, and sulfide groups. In a growing application, ''p''-DCB is the precursor to the high performance polymer [[poly(p-phenylene sulfide)]]: :C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub> + Na<sub>2</sub>S → 1/n [C<sub>6</sub>H<sub>4</sub>S]<sub>n</sub> + 2 NaCl ==Environmental effects== ''p''-DCB is poorly soluble in water and is not easily broken down by soil organisms. Like many hydrocarbons ''p''-DCB is lipophilic and would accumulate in the fatty tissues. ==Health effects== The US [[Department of Health and Human Services]] (DHHS) has determined that p-DCB may reasonably be anticipated to be a [[carcinogen]], although there is no direct evidence.{{Fact|date=June 2008}} Animals given very high levels in water developed [[liver]] and [[kidney]] [[tumor]]s. The [[United States Environmental Protection Agency]] (EPA) has set a maximum contaminant level of 75 micrograms of p-DCB per liter of [[drinking water]] (75 μg/L). p-DCB is also an EPA-registered pesticide.{{Fact|date=June 2008}} The US [[Occupational Safety and Health Administration]] (OSHA) has set a maximum level of 75 parts of p-DCB per million parts air in the workplace (75 ppm) for an 8-hour day, 40-hour [[workweek]].{{Fact|date=June 2008}} Little information is available on how children react to p-DCB exposure. ==References== {{reflist}} ==External links== *[http://npic.orst.edu/capro/Mothballs1.pdf National Pesticide Information Center - Mothballs Case Profile] *{{ICSC|0037|00}} *http://news.bbc.co.uk/2/hi/health/5219646.stm {{DEFAULTSORT:Dichlorobenzene, 1,4-}} [[Category:Organochlorides]] [[Category:Organochloride insecticides|Dichlorobenzene, 1,4-]] [[Category:IARC Group 2B carcinogens|Dichlorobenzene, 1,4-]] [[de:Paradichlorbenzol]] [[fr:Paradichlorobenzène]] [[nl:1,4-dichloorbenzeen]] [[ja:パラジクロロベンゼン]]