The invention relates to the technical field of
pigment synthesis, in particular to a production process of
pigment yellow 139, which comprises the following steps: 1) adding water into
barbituric acid, fully dissolving at the temperature of 30-70 DEG C, adjusting the pH value to be less than or equal to 1.8 to form a supersaturated solution, keeping the temperature unchanged, adding 1, 3-diimino
isoindoline solid or a
mixed solution of the 1, 3-diimino
isoindoline solid and the water for multiple times, and reacting the
barbituric acid with the 1, 3-diimino
isoindoline solid to obtain a mixture; the
molar ratio of the 2, 3-diimino isoindoline to the 2, 3-diimino isoindoline is (2.5-4.5): 1, keeping the pH value of the
system to be less than 7 in the adding process, and then keeping the temperature at 40-70 DEG 2) crude product separation: after the heat preservation reaction is finished, keeping the temperature of the
mixed solution in the step 1) at 50 DEG C or above, and carrying out hot
filtration to separate a
pigment crude product; 3) pigmentation: adding water into the pigment crude product, preserving heat at 105-130 DEG C for pigmentation within 4-10 hours to obtain a pigment yellow 139 product; and 4) carrying out heating reduced pressure
distillation treatment on the filtrate obtained by hot
filtration separation in the step 2) to obtain a
barbituric acid aqueous solution and
ammonia water. The
raw material utilization rate is improved.