1. Chemical Structure and Properties
Molecular Formula: C₂H₄Cl₂
Structural Formula:
Cl-CH₂-CH₂-Cl – A chlorinated hydrocarbon with two chlorine atoms on adjacent carbons (1,2-dichloroethane).
Physical Properties:
Appearance: Colorless, volatile liquid with a chloroform-like odor.
Boiling Point: 83.5°C; Melting Point: -35°C
Density: 1.253 g/cm³
Solubility: Slightly soluble in water (0.8% w/w at 20°C); miscible with most organic solvents (e.g., ethanol, ether)
Vapor Pressure: 61 mmHg at 20°C
Flash Point: 13°C (flammable)
Chemical Properties:
Reactivity: Undergoes dehydrochlorination to form vinyl chloride under alkaline conditions.
Stability: Stable under neutral conditions; reacts violently with strong oxidizers (e.g., KMnO₄).
Flammability: Forms explosive mixtures with air (LEL: 6.2%, UEL: 16%).
2. Industrial Applications
Chemical Synthesis:
Vinyl Chloride Precursor: Primary intermediate in PVC production via thermal cracking.
Solvent: Used in adhesives, paint strippers, and degreasers.
Pharmaceuticals:
Extraction Agent: Isolates alkaloids and steroids in drug manufacturing.
Agriculture:
Fumigant: Historical use in grain storage (now restricted due to toxicity).
Textiles:
Dye Carrier: Enhances dye solubility in synthetic fiber processing.
3. Safety and Toxicology
Acute Exposure:
Inhalation (≥100 ppm): Causes dizziness, nausea, and CNS depression (TLV-TWA: 10 ppm).
Skin Contact: Irritates skin; absorbed through skin (rabbit LD₅₀: 730 mg/kg).
Ingestion: Highly toxic (oral LD₅₀ rat: 110 mg/kg); liver and kidney damage.
Chronic Effects:
Carcinogenicity: IARC Group 2B (possibly carcinogenic); linked to liver and lung tumors in rodents.
Reproductive Toxicity: Potential teratogen (EU CLP: Repr. 1B).
Protection Measures:
PPE: Butyl rubber gloves, full-face respirators, and chemical-resistant suits.
Storage: Store in sealed containers away from heat and oxidizers.
4. Environmental and Regulatory Compliance
Environmental Impact:
Biodegradability: Slow (OECD 301F: <10% degradation in 28 days).
Aquatic Toxicity:
LC₅₀ (fish, 96h): 10–50 mg/L
EC₅₀ (daphnia, 48h): 5–20 mg/L
Bioaccumulation: Moderate (log Kow: 1.5); persists in soil and groundwater.
Regulatory Frameworks:
EU: REACH: Restricted (Annex XVII); CLP classified as Carc. 2 (H351) and Repr. 1B (H360D).
USA: EPA: Regulated under TSCA; listed as a hazardous air pollutant (HAP).
OSHA: PEL: 1 ppm (8-hour TWA).
China: GB 13690-2009: Classified as Hazardous Chemical (Class 6.1).
Waste Management:
Incinerate in high-temperature facilities with HCl scrubbers; landfill disposal prohibited.
5. Case Studies and Application Insights
Case 1: PVC Production Reformulation (Dow Chemical, 2021)
Challenge: Reduce reliance on 1,2-dichloroethane due to toxicity concerns.
Solution: Transitioned to ethylene dichloride-free PVC processes using bio-based feedstocks.
Result: Cut worker exposure risks by 50% and met EU REACH restrictions.
Case 2: Sustainable Adhesive Development (Henkel, 2022)
Process: Replaced 1,2-dichloroethane with ethyl lactate in industrial adhesives.
Impact: Reduced VOC emissions by 40% and achieved ISO 14001 compliance.
Comparative Analysis:
1,2-Dichloroethane vs. Trichloroethylene:
Pros: Higher solvency for polar resins; lower cost.
Cons: Higher carcinogenicity and environmental persistence.
1,2-Dichloroethane vs. Methylene Chloride:
Pros: Faster evaporation; better compatibility with PVC.
Cons: Methylene chloride has lower acute toxicity but similar carcinogenic risks.
Specifications:
The chemical compound 1,2-dichloroethane, commonly known as ethylene dichloride (EDC), is a chlorinated hydrocarbon. It is a colourless liquid with a chloroform-like odour. The most common use of 1,2-dichloroethane is in the production of vinyl chloride, which is used to make polyvinyl chloride (PVC) pipes, furniture and automobile upholstery, wall coverings, housewares, and automobile parts. 1,2-Dichloroethane is also used generally as an intermediate for other organic chemical compounds, and as a solvent. It forms azeotropes with many other solvents, including water (at a boiling point of 70.5 °C or 158.9 °F or 343.6 K) and other chlorocarbons.