508 M. Rieth on Acetylene. 



heated, it decomposes at a comparatively low temperature, in ac- 

 cordance with the equation 



€ 9 H 10 O 2 =€ 8 H 10 + €O 2 . 



This new hydrocarbon, which Fittig calls isoxylole, is easily ob- 

 tained quite pure. Its nitro-derivatives exhibit the greatest 

 analogy to the nitro-derivatives of the xylole from coal-tar. 

 Yet when isoxylole is oxidized, its behaviour is totally dif- 

 ferent. Xylole is easily oxidized by nitric acid to toluylic acid ; 

 isoxylole is scarcely, if at all, acted on by this agent; while sul- 

 phuric acid and bichromate of potassium, which rapidly oxidize 

 xylole to terephthalic acid, slowly oxidize isoxylole to an acid iden- 

 tical in composition with phthalic and terephthalic acids, but quite 

 different in properties. This acid he names isophthalic acid. The 

 difference is also met with in the salts of the acid. 



In order to prepare a compound which should be analogous to 

 silicon-methyle, or ethyle,FriedelandLadenburg* tried the action 

 of chloride of carbon, G CI 4 , on zincethyle, but were as unsuc- 

 cessful in obtaining definite results as had been Rieth and Beil- 

 stein before them. By acting upon zincethyle, however, with 

 methylchloracetolet, G 3 H 6 CI 2 , a better result was obtained. 

 The reaction, which does not occur at ordinary temperatures, is 

 extremely violent when once commenced, and requires great care 

 to control it. The residual mass, containing much zincethyle, is 

 treated with a large quantity of water, and, after acidifying with 

 hydrochloric acid, the supernatant liquid is removed, appropriately 

 purified, and rectified. It boils between 85° and 90°, and was 

 found, on analysis, to have the formula G 7 H 16 ; from this and 



r CH 3 



C 2 H 5 

 its mode of formation it must have the constitution G< £, 2 tjs • 



^€H 3 



Rieth % describes a method of preparing acetylene, in which an 

 accident that not unfrequently happens in a Bunsen's burner, 

 namely the striking down of the flame, is turned to account. 



The light of a Bunsen's burner is caused to strike down, 

 and then the supply of gas is increased ; over the burner is sus- 

 pended a glass funnel, and by means of an aspirator the products 

 of combustiou are drawn off: they are rich in acetylene; and on 

 allowing the gases to bubble through four Woulfe's bottles con- 

 taining ammoniacal solution of silver, even the last gave a copious 



* L'Institut, No. 1716. 



t Phil. Mag. S. 4. vol. xxix. p. 306. 



X Zeitschrlft fiir Chemie, vol. iii. p. 598. 



