1,4-Dichlorobenzene

From Infogalactic: the planetary knowledge core
Jump to: navigation, search

<templatestyles src="Module:Hatnote/styles.css"></templatestyles>

"Paracide" redirects here. For the act of killing a parent, see Parricide.
1,4-Dichlorobenzene
1,4-Dichlorobenzene
Ball-and-stick model of 1,4-dichlorobenzene
Names
IUPAC name
1,4-Dichlorobenzene
Other names
para-Dichlorobenzene
p-Dichlorobenzene
p-DCB
PDB
Paramoth
Para crystals
Paracide
Dichlorocide
Identifiers
106-46-7 YesY
ChEBI CHEBI:28618 N
ChEMBL ChEMBL190982 N
ChemSpider 13866817 N
Jmol 3D model Interactive image
KEGG C07092 YesY
RTECS number CZ4550000
UNII D149TYB5MK YesY
  • ClC1=CC=C(Cl)C=C1
Properties
C6H4Cl2
Molar mass 147.00 g·mol−1
Appearance Colorless/white crystals[1]
Odor mothball-like[1]
Density 1.25 g/cm3, solid
Melting point 53.5 °C (128.3 °F; 326.6 K)
Boiling point 174 °C (345 °F; 447 K)
10.5 mg/100 mL (20 °C)
Vapor pressure 1.3 mmHg (20°C)[1]
Vapor pressure {{{value}}}
Related compounds
Related compounds
 1,2-Dichlorobenzene
1,3-Dichlorobenzene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

1,4-Dichlorobenzene (p-DCB or para-dichlorobenzene, sometimes abbreviated as PDB or para) is an organic compound with the formula C6H4Cl2. This colorless solid has a strong odor. In terms of its structure, the molecule consists of two chlorine atoms substituted for hydrogen at opposing sites on a benzene ring. p-DCB is used as a pesticide and a deodorant, most familiarly in mothballs in which it is a replacement for the more traditional naphthalene due to its flammability. p-DCB is also used as a precursor in the production of the polymer poly(p-phenylene sulfide).[2]

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]

Uses

Disinfectant, deodorant, and pesticide

p-DCB is used to control moths, moulds, and mildew.[3] It also finds use as a disinfectant[2] in waste containers and restrooms and is the characteristic smell associated with urinal cakes. Its usefulness for these applications arises from p-DCB's low solubility in water and its relatively high volatility: it sublimes readily near room temperature.[2]

Precursor to other chemicals

Nitration gives 1,4-dichloronitrobenzene, a precursor to commercial dyes and pigments.[4] The chloride centres on p-DCB can be substituted with hydroxylamine, and sulfide groups. In a growing application, p-DCB is the precursor to the high performance polymer poly(p-phenylene sulfide):[5]

Synthesis of Polyphenylensulfide

Environmental and health 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.

The United States 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.[6] This has been indicated by animal studies, although a full-scale human study has not been done.[7] 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).[8] p-DCB is also an EPA-registered pesticide.[9] The United States 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]

Under California's Proposition 65, p-DCB is listed as "known to the State to cause cancer".[10] A probable mechanism for the carcinogenic effects of mothballs and some types of air fresheners containing p-DCB has been identified.[11][12]

See also

References

  1. ↑ 1.0 1.1 1.2 Cite error: Invalid <ref> tag; no text was provided for refs named PGCH
  2. ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ K. Hunger. W. Herbst "Pigments, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2012. doi:10.1002/14356007.a20_371
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Preamble to the IARC Monographs definition of "Group 2B: Possibly carcinogenic to humans", the International Agency for Research on Cancer classification of this chemical
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Proposition 65, Office of Environmental Health Hazard Assessment
  11. ↑ "Scientists May Have Solved Mystery Of Carcinogenic Mothballs", Physorg.com, 20 June 2006.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

Retrieved from "https://infogalactic.com/w/index.php?title=1,4-Dichlorobenzene&oldid=165109"