3057. p-Dichlorobenzene

Nomenclature

CAS number: 106-46-7
Paracide; PDB; Paradichlorobenzene; Para-zene (Reliable Chem.); Di-chloricide; Paramoth (Esquire).
C6H4Cl2; mol wt 147.00.
C 49.02%, H 2.74%, Cl 48.24%.

Description and references

Prepn and separation from m- and o-dichlorobenzene, see m-dichlorobenzene. Crystal structure of triclinic form (β-modification): Housty, Clastre, Acta Crystallogr. 10, 695 (1957); of monoclinic form (α-modification) and transformation to triclinic form: Panatoni et al., Gazz. Chim. Ital. 93, 813 (1963). Manuf: Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New Yok, 4th ed., 1975) pp 258-265. Toxicity study: T. B. Gaines, R. E. Linder, Fundam. Appl. Toxicol. 7, 299 (1986). Review of toxicology: Rev. Environ. Contam. Toxicol. 106, 51-68 (1988); and human exposure: Toxicological Profile for 1,4-Dichlorobenzene (PB99-121972, 1998) 300 pp.

Properties

Volatile crystals with a characteristic penetrating odor. Sublimes at ordinary temps. mp 53.5° (α-modification), 54° (β-modification). bp 174.12°. nD60 1.5285. Flash pt (closed cup) 150°F. Log P (olive oil/water) 3.65. Vapor pressure (25°) = 0.4 mm Hg. d20 1.46. Practically insol in water. Sol in alcohol, ether, benzene, chloroform, carbon disulfide. Non-corrosive; non-staining. LD50 in male, female rats (mg/kg): 3863, 3790 orally; >6000, >6000 dermally (Gaines, Linder).

Caution

Potential symptoms of overexposure are eye irritation, periorbital swelling; profuse rhinitis; headache; anorexia, nausea and vomiting; weight loss, jaundice and cirrhosis. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 96. Direct contact with fumes or solid may cause skin irritation. See Patty's Industrial Hygiene and Toxicology vol. 2B, G. D. Clayton, F. E. Clayton, Eds. (Wiley-Interscience, New York, 3rd ed., 1981) pp 3617-3626. This substance is reasonably anticipated to be a human carcinogen: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-85.

Use

Insecticidal fumigant. For domestic use against clothes moths; as space deodorant in room deodorizers, toilet bowl blocks and diaper pail deodorizers. Intermediate in production of plastics for electronic components.