PYROSULPHURYL CHLORIDE AND 

 CHLORSULPHONIC ACID. 



By Charles Robert Sanger and Emile Raymond Riegel. 



Presented October 13, 1909. Received January 11, 1912. 



Contents. 



Historical. 



Action of Metallic Chlorides on Sulphur Trioxide 674 



Action of Non-metalhc Clilorides on Sulphur Trioxide 675 



Action of Hydrochloric Acid on Sulphur Trioxide 680 



Relation of Pyrosulphuryl Chloride and Chlorsulphonic Acid to Each 



Other; their Separation and Purification . 681 



Historical Summary (Table I) 683 



Results of this Investigation. 



General Methods for the Preparation of Pyrosulphuryl Chloride and 



Chlorsulphonic Acid (Table II) 686 



Preparation of Pyrosulphuryl Chloride 690 



Regeneration of Chlorsulphonic Acid 692 



Properties of Pyrosulphuryl Chloride 692 



Preparation of Chlorsulphonic Acid 693 



Properties of Chlorsulphonic Acid 693 



Experimental. 



Preparations 1 to 9; Pyrosulphuryl Chloride 694 



Purification of Pyrosulphuryl Chloride and Determination of Constants 697 



Boiling Point 697 



Specific Gravity 698 



Melting Point 699 



Vapor Density 701 



Analysis 701 



Preparations 10 to 17; Chlorsulphonic Acid 702 



Purification of Chlorsulphonic Acid and Determination of Constants . 703 



Dissociation 703 



Behavior under Distillation 706 



Fractional Crystallization 709 



Melting Point 711 



Specific Gravity 711 



Boiling Point 711 



Vapor Density 711 



Analysis 712 



Properties of Mixtures of Pyrosulphuryl Chloride and Chlorsulphonic 



Acid (Table III) • 712 



Action of Water on Pyrosulphuryl Chloride and Chlorsulphonic Acid 714 



Summary 717 



VOL. XLVII. — 43 



