MER CAFTAN. 76*7 



ceous odour, boiling at 163.4 (73 cent.), and of which the 

 density is 0.825 at 68.* 



HYDROSULPHURET OF THE SULPHURET OF ETHYL, OR MERCAPTAN. 



Its formula is C 4 H 5 S + HS=ES + HS ; or it is alcohol of 

 which the oxygen is replaced by sulphur. This curious com- 

 pound, of which we owe the discovery to Zeise, may be pre- 

 pared like the preceding compound, by transmitting the vapour 

 of hydrochloric ether through a strong solution of potash,, pre- 

 viously saturated with sulphuretted hydrogen gas, or hydro- 

 sulphuret of sulphuret of potassium, KS + HS; but a preferable 

 process is to distil a strong solution of the sulphate of oxide of 

 ethyl and lime, of density 1.28, mixed with a solution of potash 

 of the same density, previously saturated with sulphuretted 

 hydrogen gas. 



KS, SH and (EO + CaO + 2SO 3 )=ES + HS andKO + SO 3 and 



CaO + SO 3 . 



The product must be received in a cool receiver. It contains 

 an excess of sulphuretted hydrogen, alcohol, and water, from 

 which it may be purified by submitting it to a second distilla- 

 tion from a small quantity of red oxide of mercury, and digesting 

 it afterwards with chloride of calcium. 



Mercaptan is a colourless liquid, highly fluid like ether, 

 having a most penetrating and insupportable garlic odour ; its 

 boiling point is about 100, according to my own observation, 

 and the density is said to be 0.835 at 70, and 0.842 at 59. 

 It is miscible with alcohol and ether, but not with water, in 

 which it is very slightly soluble. The sulphuretted hydrogen of 

 mercaptan acts powerfully on metallic oxides, water being 

 formed, and a sulphuret of the metal, which last remains in 

 combination with the sulphuret of ethyl, thus forming a class 

 of sulphur salts. The oxide of mercury is instantly converted 

 by mercaptan into a compound of this class, C 4 H 5 S + HgS,f the 

 mercaptide of mercury 9 which is a white crystalline mass, soft 

 to the touch, without odour, insoluble in water, and fusible like 

 wax by 185 (85 cent.). This mercaptide, when distilled, 

 leaves cinnabar, and affords a volatile liquid, which has not been 



* Regnault, An. de Ch. etc. Ixxi, 387. 



t Hence the name mercaptan, from mercurium cnptans. 



