Ethylene dichloride (EDC) and ethylidene chloride (EDC) are two distinct chemical compounds commonly used in various industrial applications. Although their names are similar, their properties and uses vary significantly. Understanding these differences is crucial for professionals in the chemical industry and other sectors relying on these substances.
Ethylene dichloride is primarily used in the production of vinyl chloride monomer (VCM), the precursor to polyvinyl chloride (PVC). Ethylidene chloride, on the other hand, is used as an intermediate in organic synthesis. The main difference between ethylene dichloride and ethylidene chloride lies in their chemical structure and reactivity, which determines their specific applications.
In the industrial context, choosing the right chemical can impact the efficiency and safety of manufacturing processes. Ethylene dichloride is valued for its role in PVC production, while ethylidene chloride is essential for creating various organic compounds. Both chemicals have distinct physical and chemical properties that influence their handling, storage, and usage requirements.
Chemical Structure
Ethylene Dichloride Structure
Molecular Formula and Structure
Ethylene dichloride, also known as 1,2-dichloroethane, has the molecular formula C2H4Cl2. This means it consists of two carbon atoms, four hydrogen atoms, and two chlorine atoms. The structure of ethylene dichloride is simple: the two carbon atoms are connected by a single bond, and each carbon atom is also bonded to two hydrogen atoms and one chlorine atom. This forms a linear, symmetrical molecule.
Chemical Properties
Ethylene dichloride is a volatile and flammable liquid with a sweet odor. It is slightly soluble in water but mixes well with most organic solvents. Its chemical properties are influenced by the presence of chlorine atoms, which make it a good solvent for fats, oils, waxes, resins, and various organic compounds. Ethylene dichloride can undergo reactions such as hydrolysis, oxidation, and substitution.
Ethylidene Chloride Structure
Molecular Formula and Structure
Ethylidene chloride, also known as 1,1-dichloroethane, has the molecular formula C2H4Cl2. Similar to ethylene dichloride, it contains two carbon atoms, four hydrogen atoms, and two chlorine atoms. However, its structure differs. In ethylidene chloride, both chlorine atoms are attached to the same carbon atom. This gives the molecule a different shape and chemical behavior compared to ethylene dichloride.
Chemical Properties
Ethylidene chloride is a colorless, volatile liquid with a chloroform-like odor. It is less dense than water and insoluble in it but soluble in organic solvents. The presence of both chlorine atoms on one carbon makes ethylidene chloride more reactive in certain chemical processes. It can participate in reactions like dehydrohalogenation, reduction, and addition reactions.
Production Methods
Ethylene Dichloride Production
Industrial Synthesis Methods
Ethylene dichloride is primarily produced through the chlorination of ethylene. This is an industrial process where ethylene reacts with chlorine gas:
- Direct Chlorination: Ethylene reacts with chlorine in the presence of an iron chloride catalyst, producing ethylene dichloride directly.
- Oxychlorination: Ethylene reacts with hydrogen chloride and oxygen, also yielding ethylene dichloride. This method is used when chlorine gas is not readily available.
Both methods are highly efficient and widely used in the chemical industry.
Raw Materials and Catalysts
The primary raw materials for producing ethylene dichloride are ethylene and chlorine. Catalysts such as iron chloride or copper chloride are used to speed up the reactions. In oxychlorination, oxygen and hydrogen chloride are also required. The choice of method depends on the availability of these raw materials and the specific needs of the production facility.
Ethylidene Chloride Production
Industrial Synthesis Methods
Ethylidene chloride is produced by the chlorination of ethane or by the hydrochlorination of acetylene. The processes are as follows:
- Chlorination of Ethane: Ethane reacts with chlorine, yielding ethylidene chloride along with other chlorinated hydrocarbons.
- Hydrochlorination of Acetylene: Acetylene reacts with hydrogen chloride, forming ethylidene chloride.
These methods are chosen based on the desired purity and specific industrial requirements.
Raw Materials and Catalysts
For producing ethylidene chloride, the main raw materials are ethane or acetylene and chlorine. Catalysts such as aluminum chloride or mercuric chloride may be used to facilitate the reactions. The choice of catalyst affects the yield and purity of the final product.
Physical Properties
Ethylene Dichloride Properties
Boiling Point, Melting Point, Density
Ethylene dichloride is a liquid at room temperature. It has the following physical properties:
- Boiling Point: 83.5°C (182.3°F)
- Melting Point: -35.7°C (-32.3°F)
- Density: 1.253 g/cm³ at 20°C
These properties make it suitable for use as a solvent in various industrial processes.
Solubility and Stability
Ethylene dichloride is slightly soluble in water but highly soluble in organic solvents like ethanol and ether. It is a stable compound under normal conditions but can decompose when exposed to high temperatures or strong acids, releasing toxic gases like hydrogen chloride and phosgene.
Ethylidene Chloride Properties
Boiling Point, Melting Point, Density
Ethylidene chloride also exists as a liquid at room temperature with these properties:
- Boiling Point: 57.3°C (135.1°F)
- Melting Point: -97.3°C (-143.1°F)
- Density: 1.176 g/cm³ at 20°C
Its lower boiling point compared to ethylene dichloride makes it more volatile.
Solubility and Stability
Ethylidene chloride is insoluble in water but dissolves readily in organic solvents. It is relatively stable but can react with strong bases and oxidizing agents. Upon decomposition, it produces harmful substances such as hydrochloric acid and phosgene.
Chemical Properties
Ethylene Dichloride Reactivity
Common Reactions and Uses
Ethylene dichloride is versatile in its reactivity:
- Hydrolysis: Reacts with water to form ethylene glycol and hydrogen chloride.
- Oxidation: Oxidizes to produce vinyl chloride, a precursor for PVC.
- Substitution: Undergoes substitution reactions with various nucleophiles.
It is widely used as a solvent and in the production of PVC, agrochemicals, and other organic compounds.
Reactivity with Other Chemicals
Ethylene dichloride reacts with a range of chemicals, including:
- Strong Bases: Reacts to form ethylene and chlorides.
- Acids: Can decompose to release hydrogen chloride.
- Metals: Reacts with metals like sodium, producing ethylene and metal chlorides.
Ethylidene Chloride Reactivity
Common Reactions and Uses
Ethylidene chloride is known for its reactivity in:
- Dehydrohalogenation: Forms vinyl chloride when treated with a strong base.
- Reduction: Converts to ethylene when reduced with hydrogen.
- Addition Reactions: Adds to various nucleophiles in organic synthesis.
Its primary use is in organic synthesis, creating intermediates for pharmaceuticals and agrochemicals.
Reactivity with Other Chemicals
Ethylidene chloride reacts with:
- Strong Bases: Undergoes dehydrohalogenation to form ethylene.
- Oxidizing Agents: Can be oxidized to produce acetaldehyde.
- Reducing Agents: Reduces to form ethane.
Industrial Uses
Ethylene Dichloride Applications
Usage in PVC Production
Ethylene dichloride (EDC) is a key raw material in the production of polyvinyl chloride (PVC). PVC is one of the most widely produced plastics globally. Here’s how EDC is used in PVC production:
- Vinyl Chloride Monomer (VCM) Production: EDC is converted to VCM through a process of pyrolysis. VCM is the primary building block for PVC.
- Polymerization: VCM undergoes polymerization to form PVC, which is then processed into various products.
PVC has diverse applications, including pipes, cables, and packaging materials. The demand for PVC drives the production of EDC.
Other Industrial Applications
Besides PVC production, EDC has other important industrial uses:
- Solvent: EDC is a good solvent for fats, oils, waxes, resins, and other organic substances.
- Degreasing Agent: It is used in cleaning and degreasing metals and machinery.
- Intermediate in Chemical Synthesis: EDC serves as an intermediate in the production of other chemicals, such as ethylene glycol and tetrachloroethylene.
Ethylidene Chloride Applications
Usage in Chemical Synthesis
Ethylidene chloride, or 1,1-dichloroethane, is mainly used in organic synthesis. Its reactivity makes it valuable for producing various organic compounds:
- Pharmaceuticals: It is used in synthesizing intermediates for drug development.
- Agrochemicals: It helps in producing pesticides and herbicides.
- Plastics and Resins: Ethylidene chloride is used in the synthesis of plasticizers and other additives.
Other Industrial Applications
Ethylidene chloride also finds use in several other industrial applications:
- Solvent: It acts as a solvent in chemical reactions and processes.
- Extraction Agent: It is used to extract specific compounds from mixtures due to its selective solubility properties.
- Laboratory Reagent: It is used in research and development for its chemical properties.
Health and Safety
Ethylene Dichloride Hazards
Toxicity and Exposure Risks
Ethylene dichloride poses significant health hazards:
- Inhalation: Exposure can cause respiratory issues, dizziness, and nausea.
- Skin Contact: Direct contact can lead to skin irritation and burns.
- Ingestion: Ingesting EDC can cause severe internal damage and is potentially fatal.
Long-term exposure can affect the liver, kidneys, and central nervous system. It is classified as a potential carcinogen.
Safety Measures and Handling
To ensure safety while handling EDC, follow these measures:
- Protective Gear: Use gloves, goggles, and protective clothing.
- Ventilation: Ensure proper ventilation in areas where EDC is used.
- Storage: Store in tightly closed containers in a cool, well-ventilated area.
- Emergency Procedures: Have protocols in place for spills and exposure incidents.
Ethylidene Chloride Hazards
Toxicity and Exposure Risks
Ethylidene chloride also poses health risks:
- Inhalation: Can cause respiratory problems, headaches, and dizziness.
- Skin Contact: May cause irritation or burns upon contact.
- Ingestion: Can lead to severe gastrointestinal damage and is potentially lethal.
Chronic exposure may lead to liver and kidney damage. It is considered a possible carcinogen.
Safety Measures and Handling
When handling ethylidene chloride, follow these safety precautions:
- Personal Protective Equipment (PPE): Use appropriate PPE like gloves and safety glasses.
- Proper Ventilation: Ensure good ventilation to avoid inhalation of fumes.
- Storage: Keep in a well-sealed container in a cool, dry place.
- Emergency Protocols: Establish procedures for dealing with spills and exposure.
Environmental Impact
Ethylene Dichloride Impact
Environmental Release and Degradation
EDC can have significant environmental impacts if released:
- Air: EDC can evaporate and contribute to air pollution.
- Water: It can contaminate water sources, affecting aquatic life.
- Soil: Spills can lead to soil contamination, affecting plants and microorganisms.
EDC is persistent in the environment and does not break down easily, leading to long-term pollution.
Mitigation Measures
To mitigate the environmental impact of EDC:
- Spill Containment: Use barriers and absorbents to contain spills.
- Waste Management: Dispose of EDC waste according to regulatory guidelines.
- Emission Controls: Use scrubbers and filters to reduce emissions during production and use.
Ethylidene Chloride Impact
Environmental Release and Degradation
Ethylidene chloride also impacts the environment:
- Air: It can volatilize and contribute to air pollution.
- Water: Spillage can contaminate water bodies, posing risks to aquatic organisms.
- Soil: Can lead to soil contamination, affecting local ecosystems.
It is less persistent than EDC but still poses environmental risks.
Mitigation Measures
To reduce the environmental impact of ethylidene chloride:
- Spill Response: Have a plan for containing and cleaning up spills.
- Proper Disposal: Follow regulations for disposing of chemical waste.
- Emission Reduction: Implement measures to reduce emissions during production and use.
Regulatory Aspects
Ethylene Dichloride Regulations
International Guidelines and Restrictions
Ethylene dichloride is regulated globally due to its toxicity:
- EPA: The Environmental Protection Agency (EPA) in the US has strict guidelines for its use and disposal.
- OSHA: The Occupational Safety and Health Administration (OSHA) sets exposure limits to protect workers.
- REACH: In Europe, the REACH regulation controls its manufacture and use.
These regulations aim to protect human health and the environment.
Compliance Requirements
Industries using EDC must comply with:
- Safety Data Sheets (SDS): Provide detailed information on handling and hazards.
- Exposure Monitoring: Regularly monitor and record worker exposure levels.
- Waste Management: Follow guidelines for safe disposal and recycling.
Ethylidene Chloride Regulations
International Guidelines and Restrictions
Ethylidene chloride is also subject to stringent regulations:
- EPA: It is regulated under the Toxic Substances Control Act (TSCA) in the US.
- OSHA: Exposure limits are set to protect workers from health risks.
- REACH: In Europe, its use is controlled to minimize environmental and health impacts.
These guidelines help ensure safe handling and usage.
Compliance Requirements
To comply with regulations:
- SDS: Maintain and provide safety data sheets for all users.
- Exposure Limits: Monitor and control exposure levels in the workplace.
- Waste Disposal: Adhere to regulatory requirements for safe disposal.
Comparative Analysis
Key Differences
Structural Differences
The primary difference between ethylene dichloride and ethylidene chloride lies in their chemical structure:
- Ethylene Dichloride: Chlorine atoms are attached to two adjacent carbon atoms.
- Ethylidene Chloride: Both chlorine atoms are attached to the same carbon atom.
This structural difference leads to variations in their chemical behavior and applications.
Differences in Physical and Chemical Properties
Ethylene dichloride and ethylidene chloride differ in several properties:
- Boiling Point: Ethylene dichloride has a higher boiling point (83.5°C) than ethylidene chloride (57.3°C).
- Density: Ethylene dichloride is denser (1.253 g/cm³) than ethylidene chloride (1.176 g/cm³).
- Reactivity: Ethylidene chloride is more reactive in certain chemical processes due to its structure.
These differences impact their suitability for various industrial applications.
Industrial Preference
Factors Influencing Choice
Several factors influence the choice between ethylene dichloride and ethylidene chloride:
- Application: EDC is preferred for PVC production, while ethylidene chloride is used in organic synthesis.
- Reactivity: Ethylidene chloride’s reactivity makes it suitable for specific chemical reactions.
- Regulations: Regulatory compliance may dictate the use of one compound over the other.
Cost Implications and Availability
Cost and availability also play a crucial role:
- Production Costs: The cost of raw materials and production processes can affect the choice.
- Market Availability: The availability of the chemicals in the market can influence industrial decisions.
- Environmental and Health Costs: Consideration of potential environmental and health costs is also important.
FAQs
What are the primary uses of ethylene dichloride?
Ethylene dichloride is mainly used to produce vinyl chloride monomer (VCM), a key ingredient in polyvinyl chloride (PVC) production. It is also used as an intermediate in organic synthesis and as a solvent in the extraction process for various chemicals. Its applications span industries like plastics, pharmaceuticals, and agriculture.
How does the chemical structure of ethylene dichloride differ from ethylidene chloride?
Ethylene dichloride has a structure of C2H4Cl2, featuring two chlorine atoms attached to adjacent carbon atoms. Ethylidene chloride (C2H4Cl2) differs in that its chlorine atoms are bonded to the same carbon atom. This structural difference leads to variations in their chemical properties and industrial uses.
What are the health hazards associated with ethylene dichloride?
Ethylene dichloride is toxic and can cause serious health issues if inhaled, ingested, or absorbed through the skin. It can affect the central nervous system, liver, and kidneys, and prolonged exposure may lead to more severe health conditions. Proper handling and safety measures are essential when working with this chemical.
Why is ethylidene chloride used in organic synthesis?
Ethylidene chloride is valued in organic synthesis due to its reactivity, which allows it to act as an intermediate in producing various organic compounds. Its ability to form carbon-carbon bonds makes it a useful reagent in creating complex molecules in pharmaceuticals and agrochemicals.
Conclusion
Understanding the differences between ethylene dichloride and ethylidene chloride is vital for their effective and safe use in industry. These chemicals, though similar in name, have unique properties and applications that cater to different industrial needs.
Choosing the appropriate compound depends on its intended application, chemical properties, and safety considerations. Both ethylene dichloride and ethylidene chloride play significant roles in manufacturing and synthesis, underscoring the importance of informed decision-making in chemical processes.
