IOWA ACADEMY OF SCIENCES. 
181 
Since the improvements in the electric furnace have 
rendered the manufacture of calcium carbide commercially 
practicable, the attention of chemists has been directed 
somewhat to the manufacture of the higher organic com- 
pounds from acetylene. The synthesis of ethyl alcohol, 
especially, has been the goal towards which they have striven . 
This has been accomplished in a variety of ways, but none 
of them has produced the final product so cheaply as the 
old fermentation process, and a practical commercial 
method has yet to be discovered. 
Acetylene, whose formula is C 2 H 2 , was first observed 
by Edmund Davy. Berthelot introduced the name 
‘'acetylene” and studied the gas carefully. It belongs to 
the subdivision of the hydrocarbons having the general 
name Acetylenes or Alkines and the formula CnH 2 n- 2 - 
It is therefore an unsaturated compound. Pure acetylene 
is a gas of ethereal odor. It may be liquified at-fl®, 
under a pressure of forty-eight atmospheres. It solidifies 
when rapidly vaporized and then melts at — 81^. It is 
very slightly soluble in water, but in alcohol and ether it 
will dissolve to some extent. It burns with a smoky flame, 
and with nine volumes of air, or two and one-half volumes 
of oxygen, forms an exceedingly explosive mixture. 
The chief impurities in acetylene made from commercial 
calcium carbide are hydrogen sulphide and hydrogen 
phosphene. It may be freed from these in the following 
ways : 
1. By passing the gas through an acid solution of copper 
sulphate and then through a solution of chromic acid. 
2. By passing it through porous chloride of lime. 
3. By washing it with a solution of bromine water. 
The amount of acetylene evolved from calcium carbide 
is not so great as one would expect, only five hundred feet 
of the gas being liberated from one hundred pounds of 
calcium carbide. It is partially due to this fact that no 
process of making ethyl alcohol from acetylene has as yet 
been successful. 
