Ethylene

From Sciencemadness Wiki
Jump to: navigation, search
Ethylene
Names
IUPAC name
Ethene
Systematic IUPAC name
Ethene
Properties
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)
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
219.32 J·K−1·mol−1
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 gas phase using aluminium oxide as 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 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 air.

References

Relevant Sciencemadness threads