386 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE. 



The time necessary for the establishment of equilibrium varied from 2.5 

 hours at 20° to less than 10 minutes at 70°; observations could not be com- 

 pleted in less than 5 minutes. This speed of reaction proves unnecessary 

 and even undesirable the much longer time and higher temperature generally 

 recommended for the preparation of ethyl-sulphuric acid and its salts. 



Above 70° there was found to be after the first 10 minutes a very slow 

 but steady increase of acidity with lapse of time, probably due to the forma- 

 tion of ether, the odor of which was observed, according to the equation 



C2H5HSO4 + C2H5OH = ^ CaHsOCoHs + H:S04 (G) 



It is evident that there would be a doubling of the acidity of the ethyl- 

 sulphuric acid, or a return to the acidity of the original sulphuric acid, if 

 the formation of ether were complete. To determine how rapidly this pro- 

 ceeded, the usual mixture of alcohol and sulphuric acid was kept at 140°; 

 the titrations ranged from 15.2 cc alkali at the end of 5 minutes to 23.0 ce at 

 the end of an hoiu-. The original acidity would have corresponded to 19.7 cc 

 if there had been no change in volume, but loss of ether would increase the 

 concentration of other substances, so the increase in acidity was due in part 

 to this loss of ether. The odor of ether was observed at as low a temperature 

 as 70°, though the ether reaction is general! \- lliought to begin at much higher 

 temperatures — about 130°. 



When the original mixture of alcohol and sulphuric acid was allowed 

 to stand at room temperature for a considerable time, after the rapid decrease 

 in acidity due to the formation of ethyl-sulphuric acid, practically reaching 

 equilibrium in 2.5 hours, there was a very slow further decrease in acidity, 

 the titration figure changing from 13.9 to 13.8 cc in 2 days, 13.6 cc in 7 days, 

 13.4 cc in 2 weeks, and 13.3 ce in 3 weeks. This was probably due to the 

 formation of ethyl sulphate according to equation (D), or possibly that of 

 isethionic acid or ethionic acid by reactions (K) and (Pj. This i)()int might 

 well receive further attention. 



