200 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 



condenser and was heated over a small flame. The gas as it escaped was passed 

 through a long glass tube containing cotton coated with red oxide of mercury, 

 which absorbs any possible traces of hydrogen sulphide and some of the mercaptan. 

 The gas was passed through broken ice. As the reaction above mentioned is rather 

 incomplete, the gas contains much unaltered methyl chloride. The same is true 

 when the bromide and iodide are used. Methyl chloride is the best suited to the 

 purpose, since it may be conducted into the liquid as a gas. The iodide, being a 

 very volatile liquid, is not easily added without danger of tumultuous boiling. 

 Formation of diflBcultly soluble potassium chloride or iodide causes clogging and 

 greatly interferes with the process, even when large delivery tubes are used. 



(2) Methyl sodium sulphate and potassium hydrosulphide, on being brought 

 together and warmed, yield the following reaction : 



NaCHsSO, + KHS = KNaSO^ + CH3SH. 



The reaction may be carried out in aqueous solution by the very excellent 

 method of Klason {Ber., 1887, p. 3407). 



Klason directs as follows : 



800 gm. potassium hydroxide are dissolved in water ; the solution is saturated 

 by sulphuretted hydrogen. It is placed in a large flask and sodium methyl sulphate, 

 made from 500 c.c. methyl alcohol, added in small portions. On gently warming, a 

 mixture of the vapors of (CH3)2S and CHgSH is evolved. The vapors are passed 

 through an empty bottle and then into a second bottle containing soda solution, 

 which should be cooled. The methyl hydrosulphide is completely absorbed by the 

 soda forming I^aCHsS, The sodium mercaptide so produced is very stable. Methyl 

 sulphide condenses to a liquid which floats on the soda solution, but does not combine 

 with the soda. A separation is, therefore, easily eflected. The methyl sulphide may 

 be driven off by warming the bottle containing the soda solution, the CHsS^tiTa being 

 unaffected by the heat. The methyl sulphide may thus be used in vapor form to 

 produce its reactions. After expulsion of the methyl sulphide, the soda solution 

 may be placed in a flask and decomposed by dilute sulphuric acid and CH3SH then 

 expelled as a gas. Some lead acetate is added to the solution in order to bind sul- 

 phuretted hydrogen during the decomposition of the sodium mercaptide by acid. 



Klason advises a further purification ; but, by the process described, the two 

 sulphur compounds may be obtained of sufiicient purity for the study of their reac- 

 tions. Methyl hydrosulphide is a gas above 6° C, (Klason). It is remarkable for its 

 penetrating odor, which adheres most tenaciously to all surfaces, glass not excepted, 

 for months. All work with the gas should be done out of doors. It is somewhat 

 soluble in water, to which it imparts its properties. 



