What is the use of paradichlorobenzene & its upstream and downstream industrial chain?

Paradichlorobenzene is an organic compound mainly used as insecticide, fungicide, analytical reagent, and also used in organic synthesis. At the same time, paradichlorobenzene, as a fine chemical raw material, is widely used in medicine, dyes, rubber, ink and other fields. This article will discuss the chemical properties of paradichlorobenzene, the use of paradichlorobenzene & its upstream and downstream markets, while understand its related hazards, so as to avoid use risks and environmental impacts, and promote the development of the paradichlorobenzene industry chain in a sustainable direction.

Paradichlorobenzene, also known as para-dichlorobenzene, p-Dichlorobenzene, 1,4-Dichlorobenzene, DCB, p-DCB, PDB, dichloricide, paracide, paramoth, paradow, is a colorless to white crystalline solid, almost insoluble in water, but easily soluble in alcohol and other organic solvents.

It has a melting point of 53.5°C and a boiling point of 174°C. It continues to evaporate even at room temperature and emits a strong odor. Due to this characteristic, the odor can be smelled even if there is only a trace amount in the air. Paradichlorobenzene is related to, but should not be confused with, ortho- or meta-, p- or o-dichlorobenzenes (1,2- or 1,3-forms.). Its chemical formula is C₆H₄Cl₂. 

The use of paradichlorobenzene & its upstream and downstream industrial chain

As a man-made compounds, the primarily use of paradichlorobenzene including insecticides, moth-proofing, deodorizing, antiseptic and cleaning products. It is made into mothballs and similar products to control moths, silverfish and other fiber pests in wool and other natural fiber clothing and materials.

The upstream of the paradichlorobenzene industrial chain is the supply of raw materials such as chlorine, catalysts, and paraxylene; paradichlorobenzene can be used to produce polyphenylene sulfide, moth-proofing agents, dyes, and intermediates. Among them, polyphenylene sulfide is a material widely used in aviation, automobiles, petrochemicals, medical equipment and other fields. It accounts for more than 50% of the downstream market demand for paradichlorobenzene, ranking first; anti-moth agents account for about 20%, ranking second.

With the continuous development of downstream industries, the application of paradichlorobenzene in automobiles, electronic appliances and other fields continues to deepen, and the market scale continues to expand. China's paradichlorobenzene market size was close to 2.5 billion yuan in 2022, a year-on- year increase of approximately 11% in 2021. Affected by rising raw material prices and increased market demand, the average market price of paradichlorobenzene in China has shown an upward trend in recent years, rose from about 8,200 yuan/ton in 2020 to about 12,200 yuan /ton in 2022.

How hazardous are Paradichlorobenzene products?

Paradichlorobenzene is poorly soluble in water and not easily decomposed by soil organisms. Like many aromatic hydrocarbons, it is fat-soluble and accumulates in fatty tissue.

When use of paradichlorobenzene, more than 90% of the substance evaporates into the air within a period of use or release, and it decomposes within a few days depending on weather conditions (half-life 2-6 days). Small amounts of paradichlorobenzene may become trapped in soil and water and remain viable for months. It can be absorbed by plants and animals. Generally speaking, human exposure from environmental sources is very small compared to people using these products in their homes.

Paradichlorobenzene is considered a carcinogen by the U.S. Department of Health and Human Services (DHHS) and the International Agency for Research on Cancer (IARC). The highest standard set by the U.S. Environmental Protection Agency (EPA) is that paradichlorobenzene content in drinking water does not exceed 75 micrograms/liter. It is also an EPA-registered pesticide.

The U.S. Occupational Safety and Health Administration (OSHA) standard for labor safety is that for people who work 8 hours a day and 40 hours a week, paradichlorobenzene in the air in the workplace should not exceed 75 ppm.

Most environmental pollution is caused by the manufacture, use and disposal of paradichlorobenzene consumer products. Paradichlorobenzene is relatively stable in the environment and tends to accumulate in plant and animal fats and oils, so exposure to the substance can occur through food and drinking water. It can enter the human body through inhalation, diet, or skin absorption.

Overall, as a common organic intermediate, the use of paradichlorobenzene will continue to increase driven by downstream industries, and the industry has broad development prospects. As production technology continues to advance, the quality and performance of paradichlorobenzene will continue to improve, and its application in various fields will become more widespread. Many production companies are increasing the capital investment, developing environmentally friendly and efficient production processes, updating production equipment, and improving production efficiency, to reduce pollutant emissions and promote the industry to develop in a sustainable direction.