584 PROCEEDINGS OF THE AMERICAN ACADEMY. 



was used. A hard residue which weighed 32 grams, was left in the 

 boihng flask. 



The 76 grams were distilled again. The material condensed by the 

 liquid air was 1.7 percent of the weight taken, the residue in the flask 

 also 1.7 percent. The 72 grams collected were distilled once more; 

 70.7 grams were obtained. In this third distillation, the more volatile 

 matter was less than 0.15 percent, the hard residue in flask 0.5 percent. 

 The material distilled at 49° to 70° with a pressure of 17 mm.; the 

 highest temperature of the bath was 120°, the time thirty minutes. 

 The distillations showed that the 76 grams contained no silicon tetra- 

 chloride, no sulphur trioxide, and no considerable amount of dissolved 

 or suspended silica; an analysis showed the presence of 17.2 % S and 

 49.3% CI; the silica was not determined. No crystals could be 

 formed, but the material congealed at —120°. This behavior sug- 

 gested impure chlorsulphonic acid; so in order to determine whether it 

 was present or not, 65 grams of the substance were treated with 40 

 grams of common salt.-^^ (22 grams would have been required if all 

 the sulphur found by analysis had been present as chlorsulphonic acid, 

 hence the enormous excess would be expected to retain mechanically 

 a great deal of the liquid). On adding the salt, no bubbling of hydro- 

 chloric acid gas occurred, as is always the case with chlorsulphonic 

 acid; a distillation at low pressure gave 43.5 grams of distillate. In 

 the liquid air condenser there were 3 grams of a liquid which were 

 undoubtedly uncondensed distillate and hydrochloric acid. The large 

 distillate, accompanied by the insignificant amount of hydrochloric 

 acid,-^^ established the absence of chlorsulphonic acid as an essential 

 part of the liquid. The composition was 



s Si ci 



(1) 16.9% 9.4% 53.3% 



not markedly different from that of the liquid before treatment with 

 salt. Nevertheless in subsequent mixtures a distillation from salt 

 was frequently performed, in order to remove even the smallest amount 

 of chlorsulphonic acid that might have been formed. 



The 43.5 grams were distilled twice more, at low pressure, in an 

 effort to obtain a constant boiling-point, but in neither case was the 

 temperature steady; the best result was the second fraction in the 



16 For this method of removing chlorsulphonic acid, see also Sanger and 

 Riegel, These Proceedings, 47, 689. 



17 A portion of this hydrochloric acid was formed by the action of the vapors 

 on the rubber corks and connections. 



