Microscale Gas Chemistry
 Ethene Information

A. Appearance
         Ethene is a colorless, flammable gas with a pungent odor.  It occurs naturally in ripening fruit.   Ethene is commonly called ethylene in the industrial sector of the United States.
 

B. Physical Properties of C2H4

Molecular mass:  28.0539 g/mol
melting point   -169 oC
boiling point   -103.7 oC
C. History
     Although ethene was known as a substance for quite some time, its structure (the way in which the atoms are attached) was first correctly proposed in 1864 by Alexander Crum Brown of Scotland.  His structure showed the carbon atoms forming two bonds to each other as follows:

D. Natural Abundance
     Ethene is found at low levels in natural gas deposits.
 

E. Industrial Production
    There are over 500 methods for preparing ethene! (Encyclopedia of Hydrocarbon Compounds, J. E. Faraday).  In this article we describe the preparation of ethene by two different methods.  The most familiar involves the dehydration of ethanol with sulfuric acid. (Gattermann-Wieland, Praxis des organischen Chemikers, 40th ed, Berlin, 1961)

CH3CH2OH(l) + H2SO4(l)  ---->  C2H4(g) + H2SO4.H2O(l)

     An important method by which vast quantities of ethene are produced in the petroleum industry is the cracking process by which high molecular mass hydrocarbons are heated to form shorter hydrocarbons.    We will 'crack' a polyethylene polymer to produce ethene in Method II.

     Ethene also goes by its common name ethylene; the latter is widely used in industry.
 

F. Industrial Uses
     Ethene can be polymerized to form polyethylene, perhaps the most common plastic in use today.
 

G. Gas Density of C2H4
     The density of C2H4(g) 1.1467 g/L at 25 oC and standard pressure, 3% lighter than air.
 

H. Gas Solubility of C2H4
     Ethene is slightly soluble in water.  At 25  oC , 110 mL C2H4 dissolve per L of water.

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