SANGER-RIEGEL. — PYROSULPH. CHLORIDE-CHLORSULPH. ACID. 707 



of sulphuric acid, which was suggested by the specific gravity and boil- 

 ing point of Preparation 11, the subsequent preparations were distilled 

 with hydrochloric acid, as described above. 



Preparation 12 boiled from 147° to 151°, became viscous at —138- 

 130°, and had a specific gravity of 1.745 at 20°. Distilled at low pres- 

 sure, it boiled from 77° to 81° (24-31 mm.), softened at —130-125°, 

 with specific gravity of 1.765. Three more distillations at low pressure 

 did not essentially change these properties, and the preparation was 

 evidently as pure as this treatment was likely to make it. 29 grams 

 boiled at 145-150.5° for the first half; 150.5-152° (762 mm.) for the 

 second. The presence of white fumes of sulphur trioxide towards the 

 end emphasized the decomposition, and about half a gram of residue 

 was left, which was mainly sulphuric acid. A vapor density determi- 

 nation in aniline (184°) gave 2.6 and 2.4 (theory, 4.04). A volumetric 

 analysis gave : chlorine, 30.00 ; sulphur, 28.02 (required, 30.43 and 

 27.52). 



We did not study the decomposition in the course of these distilla- 

 tions by means of the liquid air tube (Figure 1) as in the subsequent 

 trials. The product was probably more impure than would appear 

 from the properties, for the impurities compensated each other to a 

 certain extent. But the specific gravity and decomposition pointed to 

 the presence of sulphur trioxide at least. 



The study of the portion of Preparation 1 (46 g.), which had been 

 recovered from its sodium salt, is now of interest. This was viscous at 

 —128-125°, with specific gravity of 1.767 at 20°, and boiled at 78- 

 87° (23 mm.). On distillation at atmospheric pressure, a few drops 

 came over at 148-149°, but the greater part at 151-152°. There 

 was some decomposition and a few drops of sulphuric acid were left. 

 On distilling again, one fifth came over from 147° to 149°, the rest 

 chiefly at 150-152°. A third distillation increased the amount from 

 146° to 150° to one half, the rest mainly from 150° to 153°. Little resi- 

 due was left in the last two cases. The product now became viscous 

 at —136-127°, but at —85° crystals appeared, which melted at —69°. 

 The specific gravity was 1.755 at 20°. Two more distillations carried 

 the beginning to 140°, a third to 100°, whence came a rapid rise to 

 144°, and two more distillations brought much under 100°. Sulphuric 

 acid in small quantity was left in the flask each time, and there was 

 evidence of chlorine. The melting point of the product was —126"; 

 then crystals separated, melting at —70°. The specific gravity was 

 1.756. On distilling again, a few drops were collected below 100°. 

 These gave an oil with water, dissolving quietly. The melting point 

 was —51° (corr., — 60°). This was evidently sulphuryl chloride and 



