What Is 1,2-Dichloroethane (EDC)?
1,2-Dichloroethane, also known as ethylene dichloride or EDC, is a chlorinated hydrocarbon with the molecular formula C2H4Cl2 and the CAS number 107-06-2. It is a colourless, oily liquid with a sweet, chloroform-like odour and a molecular weight of 98.96 g/mol. The compound has a boiling point of about 83.5 °C and a density of approximately 1.25 g/cm3 at 20 °C, so it is noticeably heavier than water. EDC is produced in very large volumes worldwide because it is the principal feedstock for vinyl chloride monomer, which is in turn polymerised into PVC.
Is EDC Soluble in Water?
No, only slightly. 1,2-Dichloroethane has low solubility in water, about 8.7 g/L at 20 °C. In practice this means that when EDC contacts water it forms a separate, dense organic phase rather than dissolving completely, and because it is heavier than water the organic layer settles below the aqueous layer. EDC is, however, miscible with most common organic solvents, which is why it has been used in extraction and processing operations where a non-aqueous medium is needed.
Water: low solubility, about 8.7 g/L at 20 °C; forms a separate organic phase
Most organic solvents: miscible
Density: about 1.25 g/cm3 at 20 °C, so the organic layer sinks below water
Vapour: heavier than air and tends to collect in low-lying areas
Boiling point: about 83.5 °C
Because the two phases separate readily, water is not an effective medium for dissolving or diluting EDC, and any water that does absorb the compound must be treated as contaminated process water rather than discharged.
Main Use: Feedstock for Vinyl Chloride Monomer and PVC
The dominant use of EDC is as the feedstock for vinyl chloride monomer, abbreviated VCM. EDC is thermally cracked at high temperature to yield VCM and hydrogen chloride; the hydrogen chloride is normally recycled through oxychlorination to make additional EDC, and the VCM is then polymerised into PVC. Because of this route, EDC production capacity and demand track global PVC consumption in construction, piping, profiles, flooring and packaging. The chlorine balance of the process means that EDC plants are usually integrated with caustic chlorine and PVC units rather than operated as standalone facilities.
Other Industrial and Historical Uses
In the past EDC was used as a degreasing and extraction solvent and as a lead scavenger in leaded petrol, a use that has been phased out worldwide as leaded fuel was banned. Today the direct solvent applications of EDC are limited and are managed under strict exposure controls. The compound remains an intermediate in the manufacture of other chemicals, including ethylenediamine, which is used in chelating agents, resins and pharmaceutical intermediates, and in the production of vinylidene chloride copolymers used in barrier packaging and coatings. The correct CAS number for 1,2-dichloroethane is 107-06-2.
Safety, Health and Environmental Controls
EDC is classified as a hazardous substance. It is flammable, its vapours are heavier than air and can travel to distant ignition sources, and prolonged inhalation of high vapour concentrations can affect the nervous system and the liver. The compound is also regarded as a possible carcinogen under prolonged occupational exposure. Handling therefore follows a closed-system philosophy.
| Control point | Practical requirement |
|---|---|
| Engineering | Closed transfer, local exhaust ventilation, no open handling |
| Personal protection | Chemical-resistant gloves, goggles, suitable clothing and respiratory protection where required |
| Storage | Cool, ventilated area away from ignition sources, oxidisers and reactive metals |
| Spill response | Contain liquid, prevent entry to drains, soil and surface water |
| Waste and emissions | Recover or destroy under permitted controls; never discharge to water |
Always consult the safety data sheet and the applicable local regulations before storing, transferring or using EDC, and verify the exposure limits that apply at the point of use.
Frequently Asked Questions
Q: Is EDC chemical soluble in water?
Only slightly. 1,2-Dichloroethane dissolves to about 8.7 g/L at 20 °C and forms a separate dense organic phase rather than mixing with water.
Q: What is the CAS number of 1,2-dichloroethane?
The CAS registry number of 1,2-dichloroethane is 107-06-2; the abbreviation EDC stands for ethylene dichloride.
Q: What is EDC used for?
It is mainly used as feedstock for vinyl chloride monomer and PVC production, and as an intermediate in the synthesis of other chemicals such as ethylenediamine.
Q: What is the molecular formula of EDC?
The molecular formula of 1,2-dichloroethane is C2H4Cl2, with a molecular weight of 98.96 g/mol.
Q: Is EDC still used in gasoline?
No. Its former use as a lead scavenger in leaded gasoline has been phased out globally.
Q: Is EDC hazardous?
Yes. It is flammable, can affect the nervous system and liver after prolonged exposure, and is regulated as a hazardous substance requiring closed handling.