678 PROCEEDINGS OF THE AMERICAN ACADEMY. 



and the product "pure" chlorsulphonic acid. It boiled at 158.4° and 

 had a specific gravity of 1.776 at 18°. No sulphuryl chloride was 

 formed by the action of phosphorus pentachloride on either sulphur 

 trioxide or chlorsulphonic acid, as Williamson ^^ and Schifif ^^ had 

 stated, nor, according to Odling ^3^ by treating plumbic sulphate with 

 phosphorus oxychloride. While Michaelis did not obtain pure pro- 

 ducts, he at least brought out the association of the two bodies in the 

 chlorination product, and his results show the influence of hydration of 

 the sulphur trioxide. In another paper,^* in 1871, he obtains chlor- 

 sulphonic acid from sulphuryl chloride and water and from sulphuryl 

 chloride and sulphuric acid. The Carius ^^ reaction of phosphorus 

 pentachloride on plumbic sulphate gave neither body. In a third 

 paper 26 in 1873 he makes chlorsulphonic acid from concentrated sul- 

 phuric acid and phosphorus trichloride in a current of chlorine. Geu- 

 ther 27 had tried this without chlorine. 



Miiller^s in 1873 prepares "chlorsulphonic acid" with phosphorus 

 pentachloride and " moderately fuming " sulphuric acid. He also dis- 

 tils a mixture of fuming sulphuric acid and phosphorus pentoxide in a 

 current of hydrochloric acid gas, and considers the product identical 

 with that made by the action of hydrochloric acid on sulphur trioxide. 

 There are no data by which the quality of these preparations may be 

 judged, and they were probably quite impure. Clausnizer 29 in 1878 

 prepares chlorsulphonic acid according to Michaelis by action of phos- 

 phorus trichloride on sulphuric acid in a current of chlorine, obtaining 

 a boiling point of 150-151° at 726 mm. Thorpe 30 hi 1880 uses the 

 Rose reaction with sulphur monochloride to prepare " pyrosulphuryl 

 chloride," which boils at 139.59°, corr., with specific gravity 1.85846 at 

 0° referred to water at 4°. By action of phosphorus oxychloride on 

 " the strongest oil of vitriol," he prepares " chlorsulphonic acid," boil- 

 ing at 155.3°, corr., with specific gravity of 1.78474. He finds that 

 chlorsulphonic acid is completely converted to sulphuryl chloride and 

 sulphuric acid by heating for some hours at 200°. 



Ogier^i in 1882, during a thermochemical study of the oxychlorides 

 of sulphur, prepared pyrosulphuryl chloride by the first method of 

 Rose; the product boiling at 140.5° and reacting quietly with water. 

 A preparation of " chlorsulphonic acid " by the Armstrong reaction of 

 sulphur trioxide and chloroform showed violent action with water. No 



23 Gmelin, Handbuch, 1, 169. 28 Ibid., 6, 227 (1873). 



2* Jena Zeitschr., 6, 293 (1871). 29 ibid., H, 2007 (1878). 



25 Ann., 106. 307 (1858). »<» J. Chem. Soc, 37, 3.58 (1880). 



26 Ibid., 170, 1 (1873). 3i Compt. rend., 94, 82 (1882). 



27 Ber., 5, 924 (1872). 



