Section III, 1922 [307] Trans. R.S.C. 



Solubility of Cyclohexane in Liquid Sulphur Dioxide 



By W. F. Sever, Ph.D., and V. Dunbar 



Presented by E. H. Archibald, F. R.S.C. 



(Read May Meeting, 1922) 



In 1918, in the Metallurgical and Chemical Engineering Journal, 

 there appeared an article by G. J. Moore, J. Morrell and Gustave 

 Eglpfï on the solubility of paraffins, aromatics, naphthenes and olefins 

 in liquid SO2. They claimed, in the course of this investigation, to 

 have obtained evidence pointing to compound formation between 

 cyclohexane and liquid SO2. These evidences, however, seemed to be 

 of a questionable nature, in as much as statements such as these 

 occur in the article. "The present work, however, indicates that 

 naphthenes vary in solubility from to 100 per cent, depending upon 

 the temperature and cowcew/ra/ioM 0/ the liquid SO2." • • . "Below 49 

 per cent. SO2, that is, nearly an equal volume, there is no solubility 

 at 18°C., and only 3 per cent at 4.5°. With about 70 per cent SO2, 

 however, the solubility shows a marked increase. One marked peculiarity 

 of the naphthene action with SO2 is that as the concentration of the 

 SO2 reached a point between 83 and 87 per cent, white crystals 

 appeared in the oils, remaining upon the addition of more SO2." 



"This peculiarity of behaviour, together with the marked in- 

 crease in solubility at about 70 per cent., seems to point to some 

 compound between the SO2 and the naphthenes." 



In carrying out their solubility measurements the above men- 

 tioned investigators used a graduated burette stoppered at both ends. 

 A certain amount of cyclohexane was run in and then the liquid SOo. 

 In this article they appear to confuse concentration of the SO2 with 

 the amount present in the burette, which are two very different 

 things as the two liquids are only slightly soluble in each other over 

 the range of temperature that they worked. In view of the above 

 statements and the fact that Messrs. Moore, Morrell and Egloff based 

 a method of separation of paraffins and naphthenes on these dis- 

 coveries, it was thought worth while to re-determine the solubility 

 of cyclohexane in liquid SO2. 



The cyclohexane used was obtained from the Eastman Kodak 

 Co. It had a boiling point of 79°, freezing point of 6.4°, and showed 

 no signs of unsaturation. It was dried by refluxing over sodium. 



