710 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



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83 g. were then remelted and allowed to partly crystallize, and from the 

 second, half-melted mass 42 g. were taken out. After three more sim- 

 ilar fractional crystallizations, 8 g. were finally obtained, which became 

 viscous at— 130°, crystallized at —98°, and melted at —72° (—80°, corr.). 

 This product reacted quickly and violently with water, and left no oil. 



A gravimetric analysis gave : S, 

 27.66 ; CI, 30.32 (Calculated: 27.52 

 and 30.43). When cooled below 

 —85°, crystallization was not set up 

 by addition of crystals of either sul- 

 phuryl chloride or pyrosulphuryl 

 chloride. On stirring or upon addi- 

 tion of crystals of chlorsulphonic 

 acid, the separation was immediate. 



Now, as we had satisfied ourselves 

 by experiment that small amounts of 

 both sulphuryl chloride and p}Tosul- 

 phuryl chloride would alter the 

 melting point appreciably ; as both 

 of these substances gave a residual 

 oil with water, even when present in 

 small quantity, and, finally, as the 

 method of preparation precluded 

 even traces of either substance, we 

 could not but conclude that this 

 preparation of chlorsulphonic acid 

 was very pure, and that the true 

 melting point must be in the region of —80°. It remained, therefore, to 

 repeat the fractional crystallization in such a manner that access of 

 moisture to the avid chlorsulphonic acid should be avoided as far as 

 possible. 



For this purpose, the apparatus shown in Figure 3 was devised, which 

 consists of the glass separator, F, and test tube, E. The construction 

 is clear from the figure, except that P is a perforated platinum cone 

 fitting snugly into the lower part of F. F, in this case of 50 c. c. cap- 

 acity, can be placed in a liquid air container. The outlet tubes at A 

 and D are connected with drying tubes of phosphorus pentoxide. 

 Through B may be passed a stirrer. By closing B and applying suction 

 at A, the liquid is drawn from E into F. When the liquid has been 

 partly solidified in F by immersion in the cooler, the residual melted 

 portion is drawn back into a fresh test tube in place of E, while the 

 crystals are held back by the platinum cone. The crystals are then 

 melted in F and drawn into a third test tube at E. 



Figure 3. 



