| 摘要 |
PURPOSE:To purify bisazo pigment by simple operation by subjecting a mixture of three couplers and a tetrazonium salt to coupling reaction to give a mixture of bisazo compound and washing the mixture with a cleaning agent containing a compound such as dimethyl sulfoxide and an alkali metallic salt of organic acid. CONSTITUTION:A mixture of three couplers shown by formula I, formula II and formula III and a tetrazonium salt shown by formula IV are subjected to coupling reaction to give bisazo pigment (three compounds shown by formula V, formula VI and formula VII), which is cleaned with a solution containing an alkali metallic salt of organic acid and at least one selected from a group consisting of dimethyl sulfoxide, N,N-dimethylformamide and N- methylpyrrolidone to purify a mixture of bisazo pigment. A solution of the alkali metallic salt of organic acid in dimethyl sulfoxide is preferable as the cleaning solution. 10-200 pts.wt. of the cleaning solution is used based on 1 pt.wt. of the mixture of bisazo pigment and cleaning is carried out once. Bisazo pigment is suitable especially for electrophotographic sensitized material. |
