108 The Philippine Journal of Science i9i4 



DITHIOPHTHALIMIDE 



c=s 



C6H4<^NH 

 C-S 



This new and especially interesting sulphur derivative was 

 prepared from phthalimide and phosphorous pentasulphide. 

 Five grams of powdered sulphide were added to 5 grams of 

 imide dissolved in 75 cubic centimeters of boiling xylol, and 

 the heating was continued for about three hours. The solution 

 rapidly turns red with the deposition of black and purple 

 decomposition products. These are removed by decantation, and 

 the solution is allowed to cool until the greater part of unchanged 

 imide crystalhzes out. This is also removed by decantation and 

 the xylol distilled off in a current of steam. The residue was 

 alternately recrystallized from benzol and alcohol, after boiling 

 with bone black. The dithiophthalimide obtained in this manner 

 formed brilliant red needles decomposing at 180° (corrected) ; 

 yield, about 20 per cent. The compound decomposes readily, and 

 is difficult to separate from traces of phthalimide. 



Analyses of dithiophthalimide. 



Substance. ^^^'He"'' Sulphur. 



Gram. Gram. Per cent. 



0.1045 0.2475 32.54 



0.0773 0.1986 35.30 



Calculated for CsH.S^N 85.79 



Substance. '^^"^VVcTd":' Nitrogen. 



Gram. cc. Per cent. 



0.2236 12.56 7.87 



0.1515 8.76 8.10 



Calculated for CsHsS^N 7.82 



Dithiophthalimide in alcohol solution gave a complicated spec- 

 trum with a well-marked absorption band heading at - = 2020 



A 



and appearing at high concentration. A rapid extension of 

 general absorption was evident between - = 2400 and - = 2700 



A A 



and two ultra-violet absorption bands heading at - = 3020 



1 1 



and - = 3460. Incipient benzene absorption at - = 3720 was 



A. \ 



clearly indicated on the photographic plates, but the limits were 



