10 THE UNIVERSITY SCIENCE BULLETIN. 



and carbon bisulphide and then stirred for an additional hour. The 

 odor of hydrogen sulphide became noticeable, showing decomposi- 

 tion. The zinc hydroxide formed by the addition of the sodium 

 hydroxide to the zinc chloride was now added and the mixture 

 allowed to stand overnight. On distillation with steam, 15.2 gms. of 

 mustard oil, or 37.4 per cent, was isolated. 



Calcium Salt. (C,H5NHCSS),Ca. 



Parallel experiments were now made, substituting calcium for 

 barium hydroxide, the other conditions remaining the same. Very 

 little phenyl isothiocyanate was obtained, the main product being 

 thiocarbanilide. 



In the report on "The Manufacture of War Gases in Germany,"^ 

 it is stated that Kalle & Co. made the phenyl mustard oil used in 

 the preparation of phenyl iminophosgene from the calcium phenyl 

 dithiocarbamate, w^iich was then desulphurized with a mixture of 

 zinc chloride and sodium hydroxide. 



That calcium phenyl dithiocarbamate was formed from the carbon 

 bisulphide and calcium hydroxide was shown in the following ex- 

 periment : 



Aniline 28 . gms. 



Carbon bisulphide 27.2 gms. 



Calcium hydroxide 12.0 gms. in 26 cc. of water. 



Lead nitrate 100.0 gms. in 300 cc. of water. 



On the addition of the aniline there was a tendency for the mass 

 to collect in a gummy paste. This was prevented by the addition 

 of a little alcohol and stirring the mixture for 24 hours. After 

 desulphurization wdth lead nitrate 15.6 gms. of oil were isolated, 

 which corresponded to a yield of 38.4 per cent. The increase in 

 mustard oil is doubtless due to longer stirring and the more efficient 

 desulphurizing agent, lead nitrate. 



PREPARATION OF OTHER ARYL ISOTHIOCYANATES. 



The following experiments were carried out in order to ascertain 

 wiiether the method was suitable for the preparation of other aryl 

 isothiocyanates: 



o-ToLYL Isothiocyanate. o-C-H^NCS. 



o-Toluidine 32.2 gms. 



Carbon bisulphide 27.0 gms. 



Ammonia water 47.0 gms. 



Alcohol 20.0 cc. 



Lead nitrate 100.0 gms. in 200 cc. water. 



9. J. F. Norris, J. Ind. Eng. Chem. 11, 827 (1919). 



