Acid-base reactions in benzene and other organic solvents: Behavior of bromphthalein magenta with different classes of organic bases

Abstract

Practical and theoretica l aspects of acid-base reactions in benzene and other organic solvents al'e discussed . The synthesis of the indicators bromphtha lein magenta E and B (the ethyl and n-butyl esters of t etrabromopheno lph thale in ) an d of their t etraalkylammonium salts is descri bed. Qualitative and spectrophotometric data concern in g the color reactions of the indicators with primary, seconda ry, and t ertia ry a li phatic amines , s ubstituted guan idines, a nd other n itrogen bases in benz ene and other types of organic solvents are presen ted. An expla nati on off ered for the color phenom ena is also appli cable to ulfon ephthalcins and other indicators.