| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new compound useful as a pigment for optically recording medium for CD-R, DVD-R, etc., having good solubility to solvents and light resistance, etc. and capable of recycling. SOLUTION: This diaminium compound is represented by the formula [R1 is butyl; A<2-> is a divalent organic anion], e.g. naphthalene-1,5disulfonic acid N,N,N',N'-tetrakis(p-dibutylaminophenyl)-pphenylenediaminium. The compound of the formula is obtained by a method, etc., oxidizing a phenylenediamine derivative such as N,N,N',N'-tetrakis(p-dibutylaminophenyl)-p-phenyldiamine with an oxidizing agent such as silver nitrate equimolar to the phenylenediamine derivative, preferably in an organic solvent such as dimethylformamide at 5-70 deg.C and adding an acid of a divalent organic anion or its salt, e.g. disodium naphthalene-1,5-disulfonate dissolved in the organic solvent such as dimethylformamide to the reaction solution and further diluting the reaction solution with water. |
