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PROCEEDINGS OF THE AMERICAN ACADEMY 



of 160° ; it is insoluble in water, very slightly soluble in ether, benzole, 

 carbonic disulphide, glacial acetic acid, and cold alcohol ; more readily, 

 but still not very freely, soluble in hot alcohol. It is decomposed by 

 sulphuretted hydrogen into mercuric sulphide and the mercaptan. 



Parachlorbenzyldisulphide, (C 6 H 4 C1CH 2 ) 2 S 2 . 



This substance was made in several different ways : — (1.) When 

 parachlorbenzylbromide was boiled for two or more clays with an 

 alcoholic solution of potassic sulphydrate, on evaporating off the 

 alcohol a mixture of the oily mercaptan with needles of the disulphide 

 was obtained, which was exposed to the air for some time to oxidize 

 the mercaptan. (2.) The parachlorbenzylmercaptan was treated with 

 the calculated amount of bromine dissolved in ether ; the reaction is 

 as follows : — 



2C 7 H 6 C1SH + Br 2 = (C ? H 6 C1) 2 S 2 + 2HBr. 



When a large excess of bromine was added, the product was an oil 

 with an aromatic smell, the study of which is postponed for the pres- 

 ent. (3.) Parachlorbenzylbromide was warmed with an alcoholic 

 solution of sodic disulphide (Na 2 S 2 ) obtained by dissolving the calcu- 

 lated amount of flowers of sulphur in an alcoholic solution of sodic 

 sulphide (Na 2 S). The products of all these methods had the same 

 melting-point and properties. 



For analysis, a specimen prepared according to the first method 

 was purified by crystallization from alcohol and dried in vacuo. 



0.3925 gr. of the substance gave on combustion 0.7615 gr. of C0 2 

 and 0.1475 gr. of II 2 0. 



0.2540 gr. gave, according to the method of Carius, 0.3780 gr. 

 of BaS0 4 . 



Calculated for (C 7 H 6 C1) 2 S 2 . Found. 



Carbon 53.34 52.91 



Hydrogen 3.81 4.17 



Sulphur 20.32 20.44 



It forms flattened white needles with a disagreeable smell, somewhat 

 like that of the mercaptan, but much less nauseating ; melting-point 

 59° ; insoluble in water, readily soluble in alcohol, glacial acetic acid, 

 and ligroine, very soluble in ether, benzole, and carbonic disulphide. 

 Neither mercuric oxide nor mercuric chloride has any action upon it. 

 Nascent hydrogen made from zinc and dilute sulphuric acid converts 

 it into the mercaptan. 





