Ethylene

Ethylene

Names
IUPAC name Ethene
Systematic IUPAC name Ethene
Identifiers
Jmol-3D images	Image
SMILES C=C
Properties
Chemical formula	C2H4 H2C=CH2
Molar mass	28.05 g/mol
Appearance	Colorless gas
Odor	Sweet
Density	1.178 kg/m3 (15 °C)
Melting point	−169.2 °C (−272.6 °F; 104.0 K)
Boiling point	−103.7 °C (−154.7 °F; 169.5 K)
Solubility in water	2.9 mg/L
Solubility	Soluble in acetone, benzene, diethyl ether
Solubility in ethanol	4.22 mg/L
Vapor pressure	5.21·104 mmHg (25 °C)
Acidity (pKa)	44
Thermochemistry
Std molar entropy (So298)	219.32 J·K−1·mol−1
Std enthalpy of formation (ΔfHo298)	52.47 kJ/mol
Hazards
Safety data sheet	Praxair
Flash point	−136 °C (−213 °F; 137 K)
Related compounds
Related compounds	Ethane Acetylene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ethylene or ethene is a hydrocarbon which has the formula C₂H₄ or H₂C=CH₂. It is the simplest alkene.

Properties

Chemical

Ethylene is extremely flammable and will burn in an oxygen atmosphere.

C₂H₄ + 3 O₂ → 2 CO₂ + 2 H₂O

Hydration of ethene yields ethanol.

Oxidation with peracids gives ethylene oxide.

Physical

Ethylene is a colorless gas at standard conditions, lighter than air, with a sweet odor and taste.

Availability

Ethylene is sold by gas companies in gas cylinders, as compressed gas.

Preparation

Ethylene can be prepared by dehydrating ethanol in the gas phase using aluminium oxide as the catalyst.

CH₃CH₂OH → C₂H₄ + H₂O

A more accessible way is to heat ethanol with concentrated sulfuric or phosphoric acid above 180 °C. Diethyl ether appears as a side product if the temperature is too low.

Destructive distillation of HDPE will produce lots of alkanes and alkenes, including ethylene.

Projects

• Make ethylbenzene
• Make ethylene oxide
• Make polyethylene
• Plant hormone for the ripening of fruits

Handling

Safety

Ethylene is very flammable and mixtures with air can be explosive. High concentrations in closed chambers pose an asphyxiating hazard, though being lighter than air, ethylene will not build-up in closed chambers easily.

Ethylene has anesthetic effects at high concentrations.

Storage

Ethylene tanks must be kept in a cold place, away from light, heat, and corrosive vapors.

Disposal

Ethylene can be burned or released in the air.

References

Relevant Sciencemadness threads

• Preparation of ethylene
• Gamma Alumina Dehydration Of Ethanol To Ethylene
• Production of Ethene- destructive distillation of HD/LDPE
• Ethylene explorations