| 摘要 |
PURPOSE:To obtain the titled compound useful as a synthetic intermediate for pigment for recording material in high quality and yield, by adding tetramethyl-4,4'-diaminobenzhydrol to an aqueous solution of a mineral acid having a specific pH and containing m-dimethylaminobenzoic acid. CONSTITUTION:Tetramethyl-4,4'-diaminobenzhydrol having an average particle diameter of <=50mu is added as slowly as possible to an aqueous solution of a mineral acid such as hydrochloric acid, sulfuric acid, etc., of 1.5-3.0pH, preferably 2.0-3.0pH containing m-dimethylaminobenzoic acid having an average particle diameter of <=30mu and the components are made to react with each other at 50-100 deg.C to obtain the objective compond. The reaction system is preferably added with a surfactant (e.g. polyoxyethylene alkyl ether) to effect uniform dispersion of the reaction mixture. |
