OF ARTS AND SCIENCES. 283 



XXII. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 

 HARVARD COLLEGE. 



ON CHLORSULPHOPYROMUCIC ACIDS. 

 By Hexry B. Hill and Walter S. Hendrixson. 



Presented February 11, 1891. 



The sulphonic acids which may be formed by the action of fuming 

 sulphuric acids upon the several brompyromucic acids were described 

 nearly three years ago by Hill and Palmer.* The chlorpyromucic 

 acids, which were at that time unknown, were afterwards studied by 

 Plill and Jackson,t and were shown to differ in certain respects quite 

 essentially from the corresponding bromine derivatives. It therefore 

 seemed to us advisable to study also the behavior of these acids toward 

 fuming sulphuric acid. 



/3-Chlor-8-Sulphoptromucic Acid. 



/8-chlorpyromucic acid dissolves readily in fuming sulphuric acid 

 (sp. gr. 1.95), and the corresponding sulphonic acid is rapidly formed 

 without appreciable carbonization. The /3-chlorpyromucic acid itself 

 we prepared by reducing ySy-dichlorpyromucic acid with sodium amal- 

 gam containing one per cent of sodium. Complete reduction could 

 be effected by using one and a half times the calculated amount of 

 amalgam, and about fifty per cent of the theoretical yield of /3-chIor- 

 pyromucic acid was obtained. The ^-chlor-S-sulphopyromucic acid 

 was isolated in the usual way, after neutralizing the diluted acid solu- 

 tion with baric carbonate. The free acid crystallizes in hemispherical 

 masses of indistinct radiating needles, which deliquesce rapidly when 

 exposed to moist air. 



Baric ^-Chlor-h-Sidphopyromucate, BaC.HClSOg . 4H2O. 



This salt is readily soluble in hot water, more sparingly soluble in 

 cold water, and crystallizes in prisms which contam four molecules of 



* These Proceedings, xxiii. 188. t These Proceedings, xxiv 320. 



