Introduction to 1,4-Dichlorobenzene

1,4-Dichlorobenzene (C6H4Cl2) is an organic compound. Is a white crystalline solid with a characteristic sweet, mothball-like odor. It is slightly soluble in water but readily dissolves in alcohol and ether. This compound is used extensively as a pesticide, deodorizer, and in the manufacture of certain industrial chemicals.

1,4-Dichlorobenzene was first synthesized in the 19th century as part of the development of chlorobenzene derivatives. It is commonly produced by the chlorination of benzene, and it is one of the many halogenated aromatic compounds that have found broad applications across various industries. 1,4-Dichlorobenzene is primarily used in the production of mothballs, air fresheners, and deodorizers. It is also used in the synthesis of other chemicals, including some polymers and dyes. Industrially, it is typically prepared by direct chlorination of benzene, and its manufacture occurs through controlled reactions involving chlorine.

When storing 1,4-dichlorobenzene, it is important to keep it in a cool, dry, and well-ventilated area. The storage temperature should ideally be between 15 °C and 25 °C, and it should be stored in tightly sealed containers away from heat, moisture, and direct sunlight to prevent degradation and ensure safety.

Figure 1 Characteristics of 1,4-Dichlorobenzene

Agricultural Uses

Insecticide, Rodenticide, Fungicide: p-Dichlorbenzene is used primarily as an air deodorant, as moth balls, and in insecticides, which accounts for 90% of the total production of this isomer. Information is not available concerning the production and use of m-DCB.However, it may occur as a contaminant of o-or p-DCBformulations. Both o-and p-isomers are produced almost entirely as byproducts during the production of monochlorobenzene. The major uses of o-DCB are as a process solvent in the manufacturing of toluene diisocyanate and as an intermediate in the synthesis of dyestuffs, herbicides, and degreasers. The para-isomer of dichlorobenzene is the isomer most prominently used in agriculture. Not listed for use in EU countries.

Chemical Reactivity

Reactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.

Usage

The compound 1,4-dichlorobenzene is most commonly referred to as para-DCB or p-DCB. It is widely used as a moth killer, in space deodorizers, and the production of polyphenylene sulfide. It is also used in the manufacture of certain resins, in the pharmaceutical industry, and as a general insecticide in farming. At room temperature, 1,4- dichlorobenzene is a white or colorless crystalline solid with a characteristic penetrating odor. When exposed to air, it is slowly transformed from its solid state into a vapor; the released vapor then acts as a deodorizer and insect killer. It is practically insoluble in water and is soluble in alcohol, acetone, ether, chloroform, carbon disulfide, and benzene. Its chemical formula is C6H4Cl2. There is limited evidence that 1,4-dichlorobenzene can damage a developing fetus. Exposure can damage the lungs, liver, kidneys, and blood cells, causing anemia; it can also cause swelling of the eyes, hands, and feet. It can damage the nervous system, causing weakness, trembling, and numbness in the arms and legs. It may cause a skin allergy, which when developed can cause itching and a skin rash. Higher levels of the chemical in the air, such as the levels that are sometimes associated with industrial exposure, can cause headaches, nausea, clumsiness, slurred speech, and dizziness. Levels that would result in death would be associated with an odor so intense that it would be very unpleasant, if not intolerable, and would serve as a danger warning. In industrial situations, workers exposed to 1,4- dichlorobenzene at high levels are usually directed to wear respirators. Workers involved in the production of the chemical may be exposed to concentrations significantly higher than those encountered by the general population. High exposure levels may result from some consumer products of moth repellents and room deodorizers. Approximately 95% of the environmental release of 1,4- dichlorobenzene occurs during its use, rather than during its manufacture or processing.

Reference

[1] Selli E, Bianchi C L, Pirola C, et al. Efficiency of 1, 4-dichlorobenzene degradation in water under photolysis, photocatalysis on TiO2 and sonolysis[J]. Journal of Hazardous Materials, 2008, 153(3): 1136-1141.

[2] Spain J C, Nishino S F. Degradation of 1, 4-dichlorobenzene by a Pseudomonas sp[J]. Applied and Environmental Microbiology, 1987, 53(5): 1010-1019.