J922] Keaction of Methane and Also of Acetylene 75 



below the temperature of vaporization. The tetrachloride began to 

 darken at about 400°. About 13 1. of methane were used in a slow 

 stream. After about one-third of the methane had been used no 

 further volatilization of the tetrachloride was observed. When the 

 reaction tube was opened after cooling there was observed a peculiar 

 odor resembling that given off when sulphuric acid through which 

 methane has been bubbled is diluted with water. This may indi- 

 cate the formation of condensation hydrocarbons either in the drying 

 train containing P0O5 or in the reaction tube in the presence of 

 heated ZrCl^. 



The contents of the reaction tube were washed out with water to 

 remove zirconium chlorides and after thorough washing three undis- 

 solved products were distinguished under a magnifying glass as fol- 

 lows: (1) Black particles, (2) lighter brownish particles which were 

 easily blown about by slight air currents, and (3) masses which were 

 largely colorless but held small black particles disseminated through 

 them. The total yield was only a small fraction of a gram, showing 

 that in spite of prolonged heating with an excess of methane the re- 

 actions taking place were quite limited in extent. From two runs of 5 g. 

 ZrCl^ each, 0.51 g. of the black particles were obtained and the sep- 

 aration could not be looked upon as complete. 



Separation of these different particles by flotation in various 

 liquids was attempted but proved unsatisfactory. Various solvents 

 were tried also without success. Concentrated nitric acid reacted 

 upon the mixture, as also did sulphuric acid. After partial separa- 

 tion by flotation followed by picking out the particles as far as 

 possible under a magnifying glass about 0.5 gram of the black par- 

 ticles were secured and analyzed. The percentage of carbon found 

 was 82.09. Later the experiment was repeated with some additional 

 precautions and a sample obtained yielding 28.11 p.c. carbon. From 

 these analyses it was concluded that the black particles contained a 

 considerable admixture of free carbon, since the percentage for ZrC 

 is 11.69 and for ZrC^ 20.95. 



The investigation of the reaction with acetylene showed that it 

 began on gentle heating and was exothermic. Gradations in color 

 from brown-red to black were observed in the product and on wash- 

 ing with water a mixture apparently similar to the above was obtained. 



University of Noeth Carolina, 

 Chapel Hill, N. C. 



