825 



Sn- From the increase in solubilitj of rhombic sulphur in toluene 

 after heating, the quantity of Sir formed can be calculated. 



In the first place it now appeared that the equilibrium tS-. ~^ S^ 

 sets in much more slowlj in toluene than in sulphur chloride. In 

 toluene it is about six hours at 140° before the equilibrium has been 

 established, whereas in sulphur chloride at the same temperature 

 only a few minutes are required for it. (First communication, p. 

 265). In view of this 140° was chosen as lowest temperature at 

 which determinations were made. Determinations were also carried 

 out at 150° and 160° to study the influence of the temperature on 

 the equilibrium. 



The determination of the solubility of sulphur in toluene after 

 heating took place as follows: A mixture of toluene and sulphur of 

 known concentration was heated for six hours at 140°, for four 

 hours at 150° or for two hours at 160°, and then rapidly cooled, 

 in which part of the sulphur separated. After addition of a small 

 quantity of rhombic sulphur the mixture was stirred for an hour at 

 0'^. Then a sample was taken from the solution, and the sulphur 

 content was determined by evaporation of the toluene. 



The results are given in Table I. In figure 1 the solubility of the 

 sulphur after heating, is graphically i-epresented as function of the 

 concentration of the mixture. 



TABLE I. 



The lines for 140°, 150°, and 160° stop at about 36, 41, 477. 

 sulphur, mixtures of a higher sulphur content not being homogeneous 

 at these temperatures. ^) 



1) Kruyt. Zeitschr. f. physik. Chemie 65, 502, (1909). 



