SANGER-RIEGEL. — PYROSULPH. CHLORIDE-CHLORSULPH. ACID. 679 



boiling point is given for this product, and Armstrong's opinion is over- 

 looked, that the reaction gives a mixture of the two bodies. In a sec- 

 ond paper ^2 Ogier determines the vapor density of what was probably 

 the same or a similar preparation of pyrosulphuryl chloride. As his 

 analyses convinced him of the purity of his product, the deviation of 

 the density (3.70) from the theoretical (7.49), together with his ina- 

 bility to synthesize pyrosulphuryl chloride from sulphur trioxide and 

 sulphuryl chloride, causes him to find here an exception to Avogadro's 

 Kule! 



In contrast to the previous confusion, the work of Konovalofi"'^ in 

 1882 is clear. This author prepared pyrosulphuryl chloride by the 

 method of Schiitzenberger,!® using twice distilled sulphur trioxide, in 

 which, however, the actual amount of moisture was not determined. 

 During the reaction and subsequent distillation, moisture was excluded 

 and connections were of glass. The product boiled at 153° (752 mm.) ; 

 another preparation at 152.5° (740 mm.). The specific gravity was 

 1.872 at 0°. Water acted slowly. The analyses were good, and the 

 vapor density (in aniline, 7.31 ; in nitrobenzene, 7.27) showed that 

 Avogadro's Rule was not in immediate danger of overthrow. Konova- 

 loff notes that the boiling point of his product was much higher than 

 that of previous observers, notably that of Ogier, and considers that 

 previous preparations may have been contaminated with chlorsulphonic 

 acid, which dissociates easily. On mixing equal parts of his product 

 with chlorsulphonic acid prepared by the Williamson ^^ method, a boil- 

 ing point of 140-146° was obtained, with vapor density of 4.10 at 210°. 

 From four parts of water and one hundred parts of his product, he 

 obtained a liquid boiling at 139-140°, with vapor density of 4.07. 

 Ogier, 34 in reply, admitted the possibility of a small amount of chlor- 

 sulphonic acid in his product, but not enough to lower the vapor den- 

 sity to 3.70. 



Heumann and Kochlin ^'^ in 1883 were unable to synthesize pyrosul- 

 phuryl chloride from sulphur trioxide and sulphuryl chloride. Using 

 the method of Rose,* they obtained a product which they did not think 

 could contain chlorsulphonic acid, since it was " unchanged " by distil- 

 lation with phosphorus pentoxide. Yet it boiled at 145-147°, with 

 vapor densities from 5.84 in aniline to 2.58 in sulphur, and gave in- 

 conclusive figures on analysis. They think that dissociation of pyro- 

 sulphuryl chloride takes place into sulphur trioxide, sulpliur dioxide, 

 and chlorine, and is nearly complete at the boiling point of sulphur. 



32 Compt. rend., 94, 217 (1882). " ibij., ge, 66 (ISS:?). 



" Ibid., 95, 1284 (1882). ss Ber., 16, 479 (1883). 



