What is paradichlorobenzene characterized by and what is its use?

Paradichlorobenzene goes by several names: PDCB, 1,4-dichlorobenzene, p-DCB and dichlorobenzene. It is a substance formed as a result of the chlorination of an aromatic hydrocarbon (benzene) with iron chloride. What are the properties of paradichlorobenzene? What is this synthetic intermediate used for? Here are some highlights.

Paradichlorobenzene - what is it?

Chemists describe paradichlorobenzene with _{the formula C6H4Cl2} . This known intermediate belongs to the group of dichlorobenzenes, along with other isomers such as:

• 1,2 dichlorobenzene (orthodichlorobenzene, ODCB, used, among others, for chemical syntheses and production of plant protection products),
• 1,3 dichlorobenzene (meta-dichlorobenzene, used in the production of insecticides and dyes).

Dichlorobenzenes are a valuable raw material, necessary in modern industry, focused on simple and effective solutions and the production of high-quality products for homes, farms and companies.

Paradichlorobenzene: physical and chemical properties

1,4-dichlorobenzene is a white or transparent powder with a very distinct, intense odor. This raw material can be found in many different products that we use every day - it is found, for example, in air fresheners or clothes moth balls. What else is worth knowing about the physicochemical properties of paradichlorobenzene?

In contact with air, PDCB quickly changes from a solid to a gaseous state - a phenomenon chemists call sublimation. The powder is slightly soluble in water, but soluble in organic solvents. The melting point of paradichlorobenzene is 53.1°C. 1,4-dichlorobenzene starts boiling at 174.1°C.

Industrial applications of paradichlorobenzene

The biocidal properties of paradichlorobenzene and its ability to dynamically transform into gas are used on a large scale by the owners of plants producing:

• aerosols against insects (flies, blackflies, ants, aphids),
• balls in sachets, for combating clothes moths,
• fumigants, designed to exterminate various types of insects, such as: moths, hornets, wasps, mosquitoes.

The average consumer usually does not realize that paradichlorobenzene is the basic ingredient of air fresheners! These popular products are used all over the world in households, businesses and public facilities. They work well in toilets, corridors, cloakrooms, i.e. everywhere where, due to intensive use of rooms, the air quickly deteriorates, smells unpleasant and requires treatment.

Other uses of paradichlorobenzene: pharmaceutical industry and laboratories

Paradichlorobenzene also has many other applications - it is useful, among others, in specialized laboratories, where it plays the role of a reagent. In the pharmaceutical industry, PDCB is one of the so-called APIs, i.e. active substances included in medicinal products. APIs determine the specific action of drugs, for example: they cause a defensive reaction of the immune system or stimulate the work of internal organs (1,4-dichlorobenzene has a wide spectrum of activity and is increasingly used as an additive to medicines).

In the production of dyes, paradichlorobenzene successfully replaces the highly flammable naphthalene, which emits an unpleasant odor. Therefore, PDCB is used by, among others, companies that produce resins, paints, some textiles, plastics and tannins, i.e. preparations used to make leather. As an insecticide, 1,4-dichlorobenzene also works well in the woodworking process where pests can be found.

PDCB in the production of plant protection products and chemicals for agriculture

In agriculture and horticulture, paradichlorobenzene has been widely used as:

• component of pesticides and fungicides - chemical plant protection products,
• boosters (adjuvants) for herbicidal preparations,
• fertilizer component.

PDCB effectively inhibits the development of pathogenic fungi and weeds, which adversely affect the growth rate and quality of crops.

Precautions in contact with paradichlorobenzene

It is worth knowing that all the listed dichlorobenzenes (including PDCB) have been classified as highly toxic substances (different organizations, such as the WHO or the US Department of Health and Human Services, conduct research on the impact of dichlorobenzenes on health). Improperly used or stored, dichlorobenzenes can contaminate the environment, humans and animals.

In laboratory conditions, precisely secured, isolated PDCB does not have a negative impact on human health and life. Plant procedures and how the substance is stored are of key importance in the handling of 1,4-dichlorobenzene. A very important aspect regarding contact with PDCB is the correct use of personal protective equipment (masks, glasses, protecting against vapors and high-quality gloves).

Where can you buy high-quality paradichlorobenzene?

Who in Poland distributes and sells paradichlorobenzene for industry? The leader of the domestic chemical industry is currently PCC Rokita SA, which supplies the largest producers related to the industrial and agricultural sectors. High-quality 1,4-dichlorobenzene is sold, among others, by Distripark, an e-commerce wholesaler belonging to the PCC holding.

Sources:

https://encyklopedia.pwn.pl/haslo/dichlorobenzene;3892526.html

https://encyklopedia.pwn.pl/haslo/fumiganty;3903175.html