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Suggest pages1,4-Dichlorobenzene
| 1,4-Dichlorobenzene | |
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1,4-Dichlorobenzene |
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Other names
para-Dichlorobenzene |
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| Identifiers | |
| CAS number | 106-46-7  |
| ChemSpider | 13866817  |
| UNII | D149TYB5MK |
| KEGG | C07092 |
| ChEMBL | CHEMBL190982 |
| RTECS number | CZ4550000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C6H4Cl2 |
| Molar mass | 147 g mol−1 |
| Density | 1.25 g/cm³, solid |
| Melting point |
53.5 °C, 327 K, 128 °F |
| Boiling point |
174 °C, 447 K, 345 °F |
| Solubility in water | 10.5 mg/100 mL (20 °C) |
| Hazards | |
| EU classification |  Xn NCarc. Cat. 3 |
| R-phrases | R36 R40 R50/53 |
| S-phrases | (S2) S36/37 S46 S60 S61 |
| NFPA 704 |
 2
2
0
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| Flash point | 66 °C |
| Related compounds | |
| Related compounds | 1,2-Dichlorobenzene 1,3-Dichlorobenzene |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
1,4-Dichlorobenzene (para-dichlorobenzene, p-DCB, PDB) is an organic compound with the formula C6H4Cl2. This colorless solid has a strong odor. It consists of two chlorine atoms substituted at opposing sites on a benzene ring. p-DCB is used a pesticide and a deodorant, most familiarly in mothballs in which it is a replacement for the more traditional naphthalene.[1] p-DCB is also used as a precursor in the production of the polymer poly(p-phenylene sulfide).[2]
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[edit] Production
p-DCB is produced by chlorination of benzene using ferric chloride as a catalyst:
- C6H6 + 2 Cl2 → C6H4Cl2 + 2 HCl
The chief impurity is the 1,2 isomer. The compound can be purified by fractional crystallisation, taking advantage of its relatively high melting point of 53.5 °C; the isomeric dichlorobenzenes and chlorobenzene melt well below room temperature.[2]
[edit] Uses
[edit] Disinfectant, deodorant, and pesticide
p-DCB is used to control moths, moulds, and mildew. It finds use as a disinfectant[2] in waste containers and restrooms and is the characteristic smell associated with urinal cakes. Its usefulness in these arises from p-DCB's low solubility in water and its relatively high volatility: it sublimes readily near room temperature.[2]
[edit] Precursor to other chemicals
The chlorides on p-DCB can be substituted with hydroxyl, amine, and sulfide groups. In a growing application, p-DCB is the precursor to the high performance polymer poly(p-phenylene sulfide):
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[edit] 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 will accumulate in the fatty tissues.
[edit] Health effects
The US Department of Health and Human Services (DHHS) and the International Agency for Research on Cancer (IARC) have determined that p-DCB may reasonably be anticipated to be a carcinogen, although there is no direct evidence.[3] Animals given very high levels in water developed liver and kidney tumors[citation needed]. The United States Environmental Protection Agency (EPA) has set a target maximum contaminant level of 75 micrograms of p-DCB per liter of drinking water (75 μg/L).[4] p-DCB is also an EPA-registered pesticide.[5] 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.[citation needed]
Little information is available on how children react to p-DCB exposure; however, consumption of p-DCB can cause vomiting in adults.[6] A 2010 Japanese study found that the compound has anabolic-androgenic effect in rats and reduces sperm production although it does not bind to the androgen receptor, and neither does its major metabolite, 2,5-dichlorophenol.[7]
Under California's Proposition 65, p-DCB is listed as "known to the State to cause cancer".[8]
[edit] See also
[edit] References
- ^ "National Pesticide Information Center - Mothballs Case Profile". http://npic.orst.edu/capro/Mothballs1.pdf. Retrieved 2009-08-10.
- ^ a b c d 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
- ^ Preamble to the IARC Monographs definition of "Group 2B: Possibly carcinogenic to humans", the International Agency for Research on Cancer classification of this chemical
- ^ "Consumer Factsheet on: PARA-DICHLOROBENZENE (p-DCB)". November 28, 2006. http://www.epa.gov/ogwdw000/contaminants/dw_contamfs/p-dichlo.html. Retrieved 2009-08-10.
- ^ "Reregistration Eligibility Decision for Para-dichlorobenzene". December 2008. http://www.epa.gov/oppsrrd1/REDs/para-dichlorobenzene-red-revised.pdf. Retrieved 2009-08-10.
- ^ Woman Sickened by Chemical-Tainted Cup Noodle, Japan Today
- ^ Takahashi, O; Ohashi, N; Nakae, D; Ogata, A (2011). "Parenteral paradichlorobenzene exposure reduces sperm production, alters sperm morphology and exhibits an androgenic effect in rats and mice". Food and chemical toxicology 49 (1): 49–56. doi:10.1016/j.fct.2010.09.029. PMID 20932873.
- ^ Proposition 65, Office of Environmental Health Hazard Assessment
[edit] External links
- International Chemical Safety Card 0037
- Mothball sniffing warning issued, BBC News, 27 July 2006
