384 



REPORT — 1893. 



mere contiguity of an amido- or hydroxyl-group does not condition insta- 

 bility. The special properties of the /3-sulphonic derivatives of naphthalene 

 are doubtless a consequence of a structural peculiarity of the cycloid. It is 

 especially from this last point of view that observations such as are here 

 alluded to are of particular interest, and it may be permitted to draw atten- 

 tion to them as illustrating the circumstance that facts which in themselves 

 are of no special value may become of more than usual interest when con- 

 sidered in connection with the larger problems underlying all investigations 

 of details. 



In the course of the further study of the action of bromine on 

 beta-naphthol derivatives interesting results have been obtained which 

 may be here mentioned. If an aqueous solution of potassium 2 : 2' beta- 

 naphthol-sulphonate be subjected to the action of even a large excess of 

 bromine, potassium bromohydroxynaphthaquinone sulphonate is pro- 

 duced, together with a very small proportion of dibromohydroxynaphtha- 

 quinone; but if an aqueous solution of this quinone sulphonate be 

 warmed with bi'omine it becomes oxidised to a brominated sulphophthalic 

 acid ; apparently, in the former case, the presence of hydrogen bromide 

 in excess prevents the bromine acting as an oxidising agent. It is easy 

 to obtain a monobromosulphonate and the quinone sulphonate by the 

 action of bromine on an aqueous solution of Schaeffer's salt, but the 

 preparation of the intermediate di- and tri-bromosulphonates is very 

 difficult. If, however, the salt be suspended in muriatic acid it is easy to 

 convert it wholly into tribromosulphonate and to avoid the production of 

 quinone sulphonate. Recently it has been ascertained that if 2 : 3' beta- 

 naphtholsulphonic acid be dissolved in muriatic acid it is wholly con- 

 verted into tetra-bromo-beta-naphthol by the mere addition of an excess 

 of bromine ; as the product of the action of an excess of bromine on 

 beta-naphthol is a mixture of the tri- and tetra-bromo-derivative, which 

 are separated only with difficulty, this observation affords a welcome 

 method of preparing tetra-bromo-beta-naphthol. The readiness with which 

 bromine, in presence of muriatic acid, displaces the sulphonic radicle- 

 from the acid, but not from the salt, is calculated to excite surprise. 



o- Chloro-derivatives 



CI 



s/\/\ 



CI ^ \/\/ 



/\/\ NO, 



S /\/\ NO^ 



\y\/ 



Cl 



Cl 



77° 

 Cl 



ci/\/\ 



75° 



Cl 



