210 RESEARCHES UPOJiT THE CHEMICAL PROPERTIES OF GASES. 



III. SUBSTITUTION PEODUCTS OF THE ACTION OF CHLORINE UPON METHANE. 



!N^atural gas was used in the following experiment. The gas was collected in 

 June, 1888, from main conveying gas directly from Murraysville to Pittsburgh. A 

 steel cylinder provided with thoroughly tested valves was filled from the gas main 

 under a pressure of eighty pounds. An analysis of the gas showed it to have the 

 following composition : 



Methane 95.40 



Carbon dioxide 0.20 



Carbon monoxide 0. 



Ethylene 0. 



Hydrogen 0. 



Oxygen trace. 



Nitrogen » 4.40 



100.00 



The following is an outline of the process of treatment : 



Chlorine was generated in a lai'ge flask and washed in B before drying in 

 Q. JSTatural gas was freed from carbon dioxide by caustic soda, and then dried by 

 sulphuric acid. Q and C served at the same time to regulate the flow. E is a glass 

 combustion tube which was filled with bone-black previously washed by hydrochloric 

 acid. It was sought to produce the reaction : 



CH^ + 2 CI = CH3CI + HCl. 



The furnace D was kept at the lowest possible temperature necessary to cause 

 the color of the chlorine to disappear. After passing this tube, the gases were con- 

 ducted through several bottles of ferrous chloride solution to remove any excess of 

 chlorine, as well as hydrochloric acid. A reaction occurred at once in E. The chlo- 

 rine disappeared. Too high a temperature caused a pale flame to appear in the com- 

 bustion tube, which invariably led to a deposit of carbon. It was found necessary 

 to maintain a very low temperature in the combustion tube. Slight condensation 

 occurred in O of a clear liquid. Whether an excess of chlorine, or an insufiicient 

 quantity, or the theoretical quantity for the above reaction was used, there was formed 

 continuously the tetrachloride of carbon, which collected in oily drops in F and Gr. 



From experiments in using different proportions of chlorine and methane, em- 

 ploying higher and lower temperatures, and when sand or asbestos was substituted 

 for the bone-black, and in using an empty combustion tube, I am led to the conclu- 

 sion that the tendency is always to form methyl chloride and carbon tetrachloride ; 



