218 PROCEEDINGS OP THE AMERICAN ACADEMY 



Action of Bromine. 



We have as yet made but few experiments as to the action of bro- 

 mine in aqueous solution upon /3-sulphopyromucic acid. They have 

 only been sufficient to show that oxidation here follows the same course 

 that it does in the case of other derivatives of pyromucic acid, in which 

 the 8-hydrogen atom is unreplaced. At first products are formed which 

 reduce silver energetically in ammoniacal solution ; and only after 

 long warming with an excess of bromine is an acid obtained which re- 

 sembles in its behavior sulphofumaric acid. Three molecules of bro- 

 mine gave an acid whose barium salt was very readily soluble in water, 

 and which reduced silver on heating. This reaction will be studied 

 more carefully hereafter, with the hope of isolating the aldehyde acid 

 which is doubtless formed. 



Action of Fuming Sulphuric Acid upon /3S-Dibrompyro- 



mucic Acid. 



By the action of fuming sulphuric acid upon 8-brompyromucic acid, 

 we obtained a sulphonic acid which of necessity contained its sulpho- 

 group either in the |3 or in the y position. Analogy left little room 

 for doubt that the acid thus formed was in fact a /3-sul phonic acid. It 

 seemed to us not impossible that a y-sulphonic acid could be formed by 

 the action of fuming sulphuric acid upon /33-dibrompyromucic acid, 

 which still retains its -y-hydrogen atom. We found, however, that the 

 reaction takes quite a different course, and that no sulphonic acid is 

 formed. 



Pure dry /35-dihrompyromucic acid, melting at 167-108°, was slowly 

 added to several times its weight of fuming sulphuric acid. No visible 

 reaction took place, and after twenty-four hours standing water pre- 

 cipitated the acid apparently quite unchanged. After the lapse of 

 several days decomposition set in, and carbonic dioxide, bromine, 

 hydrobromic acid, and sulphurous dioxide were evolved. So slow 

 was the reaction that two or three weeks were necessary for its com- 

 pletion at ordinary temperatures. When water gave only a slight 

 flocculent precipitate, the bromine was expelled as far as possible with 

 a current of air, and the whole diluted with water. The small quan- 

 tity of insoluble matter was then removed by filtration, and the aque- 

 ous solution thoroughly extracted with ether. The ether left on 

 distillation a white crystalline acid, which, when pressed and dried, 

 melted at 127-128°. The quantity of the acid thus obtained was 



