1,4-Dichlorobenzene

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1,4-Dichlorobenzene
1,4-Dichlorobenzene 1,4-dichlorobenzene.svg
1,4-Dichlorobenzene
Ball-and-stick model of 1,4-dichlorobenzene P-Dichlorobenzene-3D-balls.png
Ball-and-stick model of 1,4-dichlorobenzene
1,4 dichlorobenzene crystallised.jpg
1,4-dichlorobenzene crystallised on paper from DCM solution
Names
Preferred IUPAC name
1,4-Dichlorobenzene
Other names
1,4-DCB
para-Dichlorobenzene
p-Dichlorobenzene
p-DCB
PDCB
Paramoth
Para crystals
Paracide
Dichlorocide
Identifiers
3D model (JSmol)
1680023
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.092 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 203-400-5
49722
KEGG
PubChem CID
RTECS number
  • CZ4550000
UNII
UN number 3077
  • InChI=1S/C6H4Cl2/c7-5-1-2-6(8)4-3-5/h1-4H X mark.svgN
    Key: OCJBOOLMMGQPQU-UHFFFAOYSA-N X mark.svgN
  • ClC1=CC=C(Cl)C=C1
Properties
C6H4Cl2
Molar mass 147.00 g·mol−1
AppearanceColorless/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]
-82.93·10−6 cm3/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Suspected carcinogen
GHS labelling:
GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Warning
H302, H315, H317, H319, H332, H335, H351, H410
P201, P202, P261, P264, P270, P271, P272, P273, P280, P281, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P308+P313, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
2
0
Flash point 66 °C (151 °F; 339 K)
Explosive limits 2.5%-? [1]
Lethal dose or concentration (LD, LC):
500 mg/kg (rat, oral)
2950 mg/kg (mouse, oral)
2512 mg/kg (rat, oral)
2830 mg/kg (rabbit, oral) [2]
857 mg/kg (human, oral)
4000 mg/kg (rat, oral)
2800 mg/kg (guinea pig, oral) [2]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 75 ppm (450 mg/m3) [1]
REL (Recommended)
Ca [1]
IDLH (Immediate danger)
Ca [150 ppm] [1]
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).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

1,4-Dichlorobenzene (1,4-DCB, p-DCB, or para-dichlorobenzene, sometimes abbreviated as PDCB or para) is an aryl chloride and isomer of dichlorobenzene with the formula C6H4Cl2. This colorless solid has a strong odor. The molecule consists of a benzene ring with two chlorine atoms (replacing hydrogen atoms) on opposing sites of the ring.

It is used as a disinfectant, pesticide, and deodorant, most familiarly in mothballs in which it is a replacement for the more traditional naphthalene because of naphthalene's greater flammability (though both chemicals have the same NFPA 704 rating). It is also used as a precursor in the production of the chemically and thermally resistant polymer poly(p-phenylene sulfide). [3]

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 crystallization, taking advantage of its relatively high melting point of 53.5 °C; the isomeric dichlorobenzenes and chlorobenzene melt well below room temperature. [3]

Uses

Disinfectant, deodorant, and pesticide

1,4-dichlorobenzene balls sold as urinal disinfectant 1,4 dichlorobenzene balls.jpg
1,4-dichlorobenzene balls sold as urinal disinfectant

p-DCB is used to control moths, molds, and mildew. [4] It also finds use as a disinfectant [3] 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. [3]

Precursor to other chemicals

Nitration gives 1,4-dichloronitrobenzene, a precursor to commercial dyes and pigments. [5] The chloride sites 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): [6]

Synthesis Poly(p-phenylene sulfide).svg

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 fatty tissues if consumed by a person or animal.

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. [7] This has been indicated by animal studies, although a full-scale human study has not been done. [8]

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), [9] but publishes no information on the cancer risk. [10] p-DCB is also an EPA-registered pesticide. [11] 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. [12] [13]

A mechanism for the carcinogenic effects of mothballs and some types of air fresheners containing p-DCB has been identified in roundworms. [14]

Due to its carcinogenic nature, use of paradichlorobenzene in the European Union is forbidden as an air freshener (since 2005) and in mothballs (since 2008).

Biodegradation

Rhodococcus phenolicus is a bacterium species able to degrade dichlorobenzene as its sole carbon source. [15]

See also

Related Research Articles

<span class="mw-page-title-main">Naphthalene</span> Chemical compound

Naphthalene is an organic compound with formula C
10
H
8
. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is the main ingredient of traditional mothballs.

<span class="mw-page-title-main">Mothball</span> Small pellets of chemical pesticide and deodorant

Mothballs are small balls of chemical pesticide and deodorant, sometimes used when storing clothing and other materials susceptible to damage from silverfish, mold or moth larvae.

<span class="mw-page-title-main">Vinyl chloride</span> Chemical compound

Vinyl chloride is an organochloride with the formula H2C=CHCl. It is also called vinyl chloride monomer (VCM) or chloroethene. This colorless compound is an important industrial chemical chiefly used to produce the polymer, poly(vinyl chloride) (PVC). Vinyl chloride monomer is among the top twenty largest petrochemicals (petroleum-derived chemicals) in world production. The United States remains the largest vinyl chloride manufacturing region because of its low-production-cost position in chlorine and ethylene raw materials. China is also a large manufacturer and one of the largest consumers of vinyl chloride. Vinyl chloride is a flammable gas that has a sweet odor and is carcinogenic. It can be formed in the environment when soil organisms break down chlorinated solvents. Vinyl chloride that is released by industries or formed by the breakdown of other chlorinated chemicals can enter the air and drinking water supplies. Vinyl chloride is a common contaminant found near landfills. Before the 1970s, vinyl chloride was used as an aerosol propellant and refrigerant.

In organic chemistry, an aryl halide is an aromatic compound in which one or more hydrogen atoms, directly bonded to an aromatic ring are replaced by a halide. The haloarene are different from haloalkanes because they exhibit many differences in methods of preparation and properties. The most important members are the aryl chlorides, but the class of compounds is so broad that there are many derivatives and applications.

<span class="mw-page-title-main">Urinal deodorizer block</span> Small disinfectant block added to urinals

Urinal deodorizer blocks are small disinfectant blocks that are added to urinals. Those containing para-dichlorobenzene (pDCB) may be called para blocks. Besides disinfecting, the purpose of these blocks is to reduce or mask odors from restroom urinals. They are placed above the urinal drain, often in the confines of a small plastic trap that prevents their loss down the drain when they dissolve to a small size.

<span class="mw-page-title-main">Iron(II) chloride</span> Chemical compound

Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a paramagnetic solid with a high melting point. The compound is white, but typical samples are often off-white. FeCl2 crystallizes from water as the greenish tetrahydrate, which is the form that is most commonly encountered in commerce and the laboratory. There is also a dihydrate. The compound is highly soluble in water, giving pale green solutions.

<span class="mw-page-title-main">1,4-Dioxane</span> Chemical compound

1,4-Dioxane is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers are rarely encountered.

<span class="mw-page-title-main">Vanadium(V) oxide</span> Precursor to vanadium alloys and industrial catalyst

Vanadium(V) oxide (vanadia) is the inorganic compound with the formula V2O5. Commonly known as vanadium pentoxide, it is a brown/yellow solid, although when freshly precipitated from aqueous solution, its colour is deep orange. Because of its high oxidation state, it is both an amphoteric oxide and an oxidizing agent. From the industrial perspective, it is the most important compound of vanadium, being the principal precursor to alloys of vanadium and is a widely used industrial catalyst.

IARC group 2B substances, mixtures and exposure circumstances are those that have been classified as "possibly carcinogenic to humans" by the International Agency for Research on Cancer (IARC) as This category is used when there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals. In some instances, an agent, mixture or exposure circumstance for which there is inadequate evidence of carcinogenicity in humans, but limited evidence of carcinogenicity in experimental animals together with supporting evidence from other relevant data may be placed in this group.

<span class="mw-page-title-main">Chlorobenzene</span> Aromatic organochlorine compound

Chlorobenzene is an aryl chloride and the simplest of the chlorobenzenes, consisting of a benzene ring substituted with one chlorine atom. Its chemical formula is C6H5Cl. This colorless, flammable liquid is a common solvent and a widely used intermediate in the manufacture of other chemicals.

IARC group 3 substances, chemical mixtures and exposure circumstances are those that can not be classified in regard to their carcinogenicity to humans by the International Agency for Research on Cancer (IARC). This category is used most commonly for agents, mixtures and exposure circumstances for which the level of evidence of carcinogenicity is inadequate in humans and inadequate or limited in experimental animals. Exceptionally, agents (mixtures) for which the evidence of carcinogenicity is inadequate in humans, but sufficient in experimental animals may be placed in this category when there is strong evidence that the mechanism of carcinogenicity in experimental animals does not operate in humans. Agents, mixtures and exposure circumstances that do not fall into any other group are also placed in this category.

1,1-Dichloroethene, commonly called 1,1-dichloroethylene or vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula C2H2Cl2. It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water, but soluble in organic solvents. 1,1-DCE was the precursor to the original clingwrap, Saran, for food, but this application has been phased out.

<span class="mw-page-title-main">1,2-Dichlorobenzene</span> Chemical compound

1,2-Dichlorobenzene, or orthodichlorobenzene (ODCB), is an aryl chloride and isomer of dichlorobenzene with the formula C6H4Cl2. This colourless liquid is poorly soluble in water but miscible with most organic solvents. It is a derivative of benzene, consisting of two adjacent chlorine atoms.

<span class="mw-page-title-main">2-Naphthylamine</span> Chemical compound

2-Naphthylamine is one of two isomeric aminonaphthalenes, compounds with the formula C10H7NH2. It is a colorless solid, but samples take on a reddish color in air because of oxidation. It was formerly used to make azo dyes, but it is a known carcinogen and has largely been replaced by less toxic compounds.

1,2,4-Trichlorobenzene is an organochlorine compound, one of three isomers of trichlorobenzene. It is a derivative of benzene with three chloride substituents. It is a colorless liquid used as a solvent for a variety of compounds and materials.

<span class="mw-page-title-main">1,3-Dichloropropene</span> Chemical compound

1,3-Dichloropropene, sold under diverse trade names, is an organochlorine compound with the formula C3H4Cl2. It is a colorless liquid with a sweet smell. It is feebly soluble in water and evaporates easily. It is used mainly in farming as a pesticide, specifically as a preplant fumigant and nematicide. It is widely used in the US and other countries, but is banned in 34 countries.

<span class="mw-page-title-main">Vinyl fluoride</span> Chemical compound

Vinyl fluoride is an organic halide with the chemical formula C2H3F. It is a colorless gas with a faint ether-like odor. It is used as the monomeric precursor to the fluoropolymer polyvinylfluoride.

<span class="mw-page-title-main">4-Nitrochlorobenzene</span> Chemical compound

4-Nitrochlorobenzene is the organic compound with the formula ClC6H4NO2. It is a pale yellow solid. 4-Nitrochlorobenzene is a common intermediate in the production of a number of industrially useful compounds, including antioxidants commonly found in rubber. Other isomers with the formula ClC6H4NO2 include 2-nitrochlorobenzene and 3-nitrochlorobenzene.

Naftalan or Naphtalan is a type of crude oil. It is named after Naftalan, Azerbaijan, where it is found. It is known for its high naphthalene content and use in alternative medicine.

Naphthalene poisoning is a form of poisoning that occurs when naphthalene is ingested. Severe poisoning can result in haemolytic anaemia. Naphthalene was introduced in 1841 by Rossbach as an antiseptic to counteract typhoid fever. Although naphthalene was widely used industrially, only nine cases of poisoning have been reported since 1947 as of 1956, suggesting underdiagnosis of the condition. As a result, the condition has limited coverage within medical journals.

References

  1. 1 2 3 4 5 6 7 NIOSH Pocket Guide to Chemical Hazards. "#0190". National Institute for Occupational Safety and Health (NIOSH).
  2. 1 2 "p-Dichlorobenzene". National Institute for Occupational Safety and Health (NIOSH). 4 December 2014. Retrieved 6 March 2015.
  3. 1 2 3 4 Rossberg, M.; Lendle, W.; Pfleiderer, G.; Tögel, A.; Dreher, E. L.; Langer, E.; Rassaerts, H.; Kleinschmidt, P.; Strack (2006). "Chlorinated Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_233.pub2. ISBN   978-3527306732.
  4. "National Pesticide Information Center – Mothballs Case Profile" (PDF). Archived from the original (PDF) on 22 June 2010. Retrieved 10 August 2009.
  5. K. Hunger. W. Herbst "Pigments, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2012. doi : 10.1002/14356007.a20_371
  6. Fahey, D. R.; Ash, C. E. (1991). "Mechanism of poly(p-phenylene sulfide) growth from p-dichlorobenzene and sodium sulfide". Macromolecules. 24 (15): 4242. Bibcode:1991MaMol..24.4242F. doi:10.1021/ma00015a003.
  7. Preamble to the IARC Monographs Archived 9 August 2016 at the Wayback Machine definition of "Group 2B: Possibly carcinogenic to humans", the International Agency for Research on Cancer classification of this chemical
  8. "ToxFAQs for Dichlorobenzenes". Toxic Substances Portal. Agency for Toxic Substances and Disease Registry. Retrieved 24 May 2013.
  9. "Consumer Factsheet on: PARA-DICHLOROBENZENE (p-DCB)". 28 November 2006. Archived from the original on 6 October 2009. Retrieved 10 August 2009.
  10. "1,4-Dichlorobenzene (para-Dichlorobenzene)". US Environmental Protection Agency. Archived from the original on 4 April 2016. Retrieved 24 March 2016.
  11. "Reregistration Eligibility Decision for Para-dichlorobenzene" (PDF). December 2008. Archived from the original (PDF) on 26 September 2009. Retrieved 10 August 2009.
  12. "Chemical Sampling – p-Diclorobenzine". United States Department of Labor. Occupational Safety & Health Administration. Archived from the original on 31 July 2017. Retrieved 23 March 2016.
  13. "Common Name: 1,4-DICHLOROBENZENE" (PDF). New Jersey Department of Health and Senior Services. December 2005. Retrieved 24 March 2016.
  14. Kokel, David (14 May 2006). "The nongenotoxic carcinogens naphthalene and para-dichlorobenzene suppress apoptosis in Caenorhabditis elegans". Nature Chemical Biology. 2 (6): 338–345. doi:10.1038/nchembio791. PMID   16699520. S2CID   18402091.
  15. Rehfuss, M.; Urban, J. (2005). "Rhodococcus phenolicus sp. nov., a novel bioprocessor isolated actinomycete with the ability to degrade chlorobenzene, dichlorobenzene and phenol as sole carbon sources". Systematic and Applied Microbiology. 28 (8): 695–701. doi:10.1016/j.syapm.2005.05.011. PMID   16261859.