In this study, a continuous-flow coupling reaction method has been developed for the synthesis of Pigment Red 146 (C.I. PR 146). A computational fluid dynamics simulation was used to evaluate the effects of the micromixer structures on the mixing process. After the optimization of the microreactor structures and the reaction conditions, the conversion of the coupling reaction reached more than 99% using a microsieve pore dispersion reactor (two microsieve pores arranged side by side) and a smaller particle size and narrower particle-size distribution were obtained than were obtained in conventional batch reactors. Furthermore, the lightness and the green and the blue hues of these pigment products were more intense than those of the C.I. PR 146 standard. The largest conformity of the hue of the pigment products compared with the C.I. PR 146 standard was obtained using a microsieve pore dispersion reactor under the optimized reaction conditions. Finally, a scaling-up study of the pigment synthesis process in the microreactor system was initially explored. In conclusion, the microreactor system led to an improvement of the pigment products, and this method has a good industrial value.

In this study, a continuous-flow synthesis of the azo pigment Yellow 14 protocol has been developed using a three-stream micromixing process. This method controlled the pH of the azo coupling reaction process accurately and conveniently. After the optimization of the reaction conditions, the pigment products had a high purity and a good chromatic light. Compared with the two-stream micromixing process, the purity of the pigment products synthesized by the three-stream micromixing process increased by 9.41%, and the color differences between pigment products and Yellow 14 standard decreased obviously. Furthermore, the transparency numbers of pigment products synthesized by the microreactor system increased by 93−99% compared with that of the Yellow 14 standard. For the chromatic light, the red and blue hues of the pigment products were more intense than those of the Yellow 14 standard. Overall, the three-stream micromixing process led to an improvement of the pigment products, and this method also has good potential in industrial applications.

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