DAINS ET AL.: ARYL ISOTHIOCYANATES. 11 



The ammonium salt crystallized out readily after addition of 

 the amine. The mixture was then brought into solution by the 

 addition of 400 cc. of water and treated as before. The weight of 

 pure o-tolyl mustard oil was 32.8 gms., or 73.27 per cent. 



m-ToLYL ISOTHIOCYANATE. m-C-H^NCS. 



Using the same proportions as before, the solid ammonium salt, 

 which is easily soluble in water, soon formed. From the reaction 

 mixture was isolated 33.5 gms. of oil, or 74.7 per cent yield. 



p-TOLYL ISOTHIOCYANATE. p-C-H-NCS. 



Under the above conditions 32.3 gms. (72.1 per cent) of the 

 p-tolyl mustard oil (b. p. 270) were obtained. 



1, 3, 4,-XyLYL ISOTHIOCYANATE. (CHg) oCeHgNCS. 



1. 3. 4-Xylidine 36.4 gms. 



Carbon bisulphide 27.0 gms. 



Ammonium hydroxide 47.0 gms. 



Lead nitrate 100.0 gms. in 200 cc. of water. 



After three hours' stirring the ammonium salt separated in coarse 

 crystals, which were dissolved in 400 cc. of water before the addi- 

 tion of the lead nitrate. The mustard oil was very slowly volatile 

 with steam, and was obtained partly by this method and partly by 

 extraction of the oily lead sulphide with carbon bisulphide. The 

 separation was not complete, and only 25.5 gms. (52 per cent) of the 

 xylyl isothiocyanate (m. p. 31°) were obtained. 



PsEUDOCrMYL IsOTHIOCY.\NATE. 1, 2, 4, 5, (CHg) aCgH^NCS. 



Pseudocumidine 20.0 gms. 



Carbon bisulphide lo-O gms. 



Ammonium hydroxide 23.0 gms. 



Alcohol 22.0 cc. 



Lead nitrate 49.0 gms. 



The ammonium salt separated after two hours' stirring. It was 

 dissolved in 1,000 cc. of water and treated with the lead nitrate in 

 the same dilution. The isothiocyanate is difficultly volatile with 

 steam, and the yield, 50.2 per cent, could probably have been in- 

 creased by extracting the sulphide residue with some solvent. 



Alpha-Naphthyl Isothiocyanate. A-CioH.NCS. 



Alpha-naphthylamine 20.0 gms. 



Carbon bisulphide 15.0 gms. 



Ammonium hydroxide 22.0 gms. 



Alcohol 20 cc. 



Lead nitrate 46.2 gms. in 200 cc. of water. 



