Industrial Chemistry 1 - Chapter 3: Ethylene Chemicals

Industrial Chemistry 1 - Chapter 3: Chemicals Based on Ethylene

• Ethylene is a hydrocarbon with the chemical formula C₂H₄.
• It's a colorless, flammable gas with a sweet, musky odor in its pure form.
• Ethylene has a simple structure and high reactivity.
• It's relatively inexpensive and produces fewer by-products compared to other olefins during reactions.
• Ethylene serves as a raw material for numerous chemicals and polymers, including ethanol and polyethylene.
• It's readily produced from various hydrocarbon sources via steam-cracking.
• Its molecular weight is 28.05 g/mol.
• Its density at 15°C is 1.178 kg/m³, in gaseous state.
• Ethylene boils at -103.7°C (169.5 K) and melts at -169.2 °C (104.0 K).

Major Chemicals and Polymers from Ethylene

• Ethylene is a precursor for many important commercial chemicals like ethylene glycol, ethanolamines, and polyesters.
• Ethylene oxide is a critical derivative, produced by controlled oxidation of ethylene over a silver catalyst.
• The reaction is exothermic.
• The production process uses multi-tubular reactors, controlling oxidation temperature with boiling water.
• Ethylene oxide undergoes a chemical reaction at ~200-300 °C, with a short residence time of about 1 second.
• Acetaldehyde is another significant product derived from ethylene.
• Acetaldehyde is a colorless liquid with a pungent odor.
• It's used primarily in the synthesis of other compounds, especially as a raw material for acetic acid production.
• Acetaldehyde production can use traditional methods like silver or chromium-activated copper catalysis, but modern techniques employ a homogenous catalyst like the Wacker process.
• The Wacker process, involving palladium and copper catalysts, is commonly used for oxidizing ethylene to acetaldehyde at 130 °C.
• The overall reaction is exothermic (with ΔH = -218.6 kJ/mol) in redox reactions for acetaldehyde production.
• Byproducts of ethylene and acetaldehyde reactions can include acetic acid, ethyl chloride, chloroacetaldehyde, and carbon dioxide.
• Ethylene's yield from either production method is approximately 95%.

Conclusion

• Ethylene is a crucial starting material for various petrochemicals and polymers.
• Continuous advancements are vital to boost its production and thus related chemicals.