680 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Possibly the work of Konovaloff had escaped their observation. Later 

 in another paper,36 from the vapor density at 184°, they decide that 

 chlorsulphonic acid (2 vols.) at that temperature is completely dis- 

 sociated into sulphur trioxide, sulphur dioxide, chlorine, and water 



(8 vols.). 



Konovaloff 3T in 1883, applying again his entirely correct theory of 

 the necessity for anhydrous reagents, obtained through the Rose reac- 

 tion with sulphur monochloride a pyrosulphuryl chloride boiling at 152- 

 153°, with vapor density of 7.2 at 210°. 



Since 1883, little more concerning the chlorination methods has been 

 published. Erdmann^s in 1893, as did Armstrong earlier, proposes 

 the reaction of Schutzenberger,^' with slight modifications, as an 

 economical method for preparing phosgene. The residue he con- 

 siders a mixture of pyrosulphuryl chloride and chlorsulphonic acid. 

 Moureau ^9 in 1894, by the action of thionyl chloride on sulphuric acid 

 of specific gravity 1.84, obtains a product boiling at 130-157°, which 

 he concludes to be a mixture of the two bodies. Prandtl and Borin- 

 ski ** have used the method of Schiitzenberger in the investigation 

 cited below, and show that both bodies are present in the reaction 

 product. 



Action of Hydrochloric Acid on Sulphur Trioxide. 



As previously mentioned, A. "Williamson, ^^ ^^ 1854 was apparently 

 the first to use this reaction, of which chlorsulphonic acid and not pyro- 

 sulphuryl chloride is the product. The reaction was repeated in 1857 

 in A. Williamson's laboratory by R. Williamson,^* but no details are 

 given. Dewar and Cranston *° in 1869, also, by the " direct action of 

 sulphuric acid on hydrochloric acid," obtain a substance "with all the 

 properties ascribed by Williamson." 



Much more definite is the work of Beckurts and Otto *i in 1878, 

 who advised the use of a fuming sulphuric acid, slightly crystalline at 

 ordinary temperature, " containing from 38 to 39 per cent of sulphur 

 trioxide." *2 Their product boiled between 149° and 152.7°, mainly 

 at 151.7-152.7°, and was apparently fairly pure. Beckurts and Otto 

 consider that, if chlorsulphonic acid and sulphuric acid give pyrosul- 



36 Ber., 16, 602 (1883). 



3' Compt. rend., 96, 1146 (1883). 



38 Ber., 26, 1990 (1893). 



39 Bull. Soc. Cliim. (3), 11, 767 (1894). 

 *« Chem. News, 20, 174 (1869). 



« Ber., 11, 2058 (1878). 



*^ This would mean about 94 per cent actual sulphur trioxide, or about 

 66 per cent available (v. Table II, p. 687). 



