Ethylene dichloride, now more commonly known as 1,2-dichloroethane, is an organic compound classified as an organochloride. This designation is recognized by several other terms, including chlorocarbon, chlorinated solvent, and chlorinated hydrocarbon, all meaning the same thing. The chemical structure of ethylene dichloride consists of a covalent bond between its hydrogen atoms and two chlorine atoms, meaning that they share electron pairs between them.
While ethylene dichloride is considered an outdated name for 1,2-dichloroethane, it was also once called Dutch oil in honor of the Dutch scientists who first synthesized this compound from ethylene and chlorine gases in the late 18th century. Today, the compound is produced in large quantities from the same basic materials using either chlorinated iron or copper as a catalyst. In fact, the commercial production of this solvent in the US, which began in 1922, eventually earned a place in the top 50 highest volume industrial chemicals produced in the country. In addition, large amounts of this chemical are imported into the US each year from Japan and several Western European countries.
The primary industrial use of ethylene dichloride is to produce vinyl chloride, used to manufacture polyvinyl chloride (PVC). It is also used to make polystyrene, a thermoplastic, and styrene butadiene (SBR) latex, an adhesive coating used to bond cement, concrete, and asphalt. In addition, the chemical is used as an industrial solvent to remove oil and grease, as well as in the manufacturing of other chlorinated solvents, such as perchloroethylene, otherwise known as dry cleaning fluid. At one time, this chemical was added to leaded gasoline as an anti-knock agent.
There are several known health hazards associated with ethylene dichloride, which is readily absorbed through the skin and lungs. In addition to causing respiratory problems, this chemical may also act on the nervous system, and damage the heart, liver, kidneys, and adrenal glands. While the US Environmental Protection Agency (EPA) classifies this substance as a “probable human carcinogen,” it is unclear whether long-term or high concentrations of exposure genuinely increase cancer risk due to other chemical contaminants being concurrently present among populations participating in occupational studies. However, studies using animal models indicate that exposure initiated by ingestion or topical application did result in the formation of various tumors of the lungs, stomach, colon, and mammary glands. In addition, a decrease in fertility was observed in rats and mice.
While exposure to ethylene dichloride was once thought to be primarily an occupational hazard, the EPA has discovered that this solvent is also present in significant amounts in rural air, as well as in surface water and groundwater. As might be expected, the World Health Organization (WHO) reports similar findings in Western Europe in regions where this chemical is manufactured. In addition, according to the US Agency for Toxic Substances and Disease Registry (ATSDR), this substance has been detected in human breast milk. In terms of environmental impact, 1,2-dichloroethane persists in the ground, but biodegrades in the air within 300 days. However, this substance is toxic to fish and contributes to acid rainfall.
