| 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 N Carc. Cat. 3 |
| R-phrases | R36 R40 R50/53 |
| S-phrases | (S2) S36/37 S46 S60 S61 |
| NFPA 704 |
2
2
0
|
| 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]
Contents |
p-DCB is produced by chlorination of benzene using ferric chloride as a catalyst:
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]
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]
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):
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.
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 . 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.
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]