| 摘要 |
<p>In the present invention there is disclosed a process for preparing isoindoline pigments of the general formula V, in which R represents hydrogen, methyl, ethyl or phenyl group by a two-stage reaction of phthalodinitrile with barbituric acid or derivatives thereof. The proposed preparation process is characterized by reacting in the first stage phthalodinitrile in an inert organic medium that is miscible with water with barbituric acid sodium or potassium salt or derivatives thereof of the general formula VI, wherein R is as specified above in molar ration 1 : 1 at pH value in the range from 8 to 14 and at a temperature ranging from 0 to 80 degC and the obtained monocondensate of the general formula VII, wherein R is as specified above is then reacted in the second stage with excess of barbituric acid or specified derivatives thereof in the presence of water and at pH value ranging from 0.1 to 6.</p> |
