Continuous-Flow Synthesis of Pigment Red 146 in a Microreactor System

Abstract

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.

Continuous-Flow Synthesis of the Azo Pigment Yellow 14 Using a Three-Stream Micromixing Process

“…The simulation parameters were consistent with the literature. 26 The small scale of the microchannel and the mixing enhanced by the rapid reactions were considered, so the K-Epsilon Model was selected for the simulations. The convergence condition was set as the RMS Res less than 1 × 10 −4 .…”

“…The commercial software Fluent 6.3 was used in this work. The simulation parameters were consistent with the literature . The small scale of the microchannel and the mixing enhanced by the rapid reactions were considered, so the K-Epsilon Model was selected for the simulations.…”

“…Zhang et al investigated the modeling of micromixing performance in micropore dispersion reactors, and the segregation indexes were found to be in the range of 10 –2 to 10 –3 , which indicated that the micropore dispersion reactors had high micromixing. Furthermore, we have used the microsieve pore dispersion reactor to synthesize the pigment red 146, and the conversion of the azo coupling reaction reached more than 99% . Based on the microsieve pore dispersion reactor we have used, the microsieve pore reactor with two micropores (two microsieve pores arranged side by side) was also used in this work.…”

“…Furthermore, we have used the microsieve pore dispersion reactor to synthesize the pigment red 146, and the conversion of the azo coupling reaction reached more than 99%. 26 Based on the microsieve pore dispersion reactor we have used, the microsieve pore reactor with two micropores (two microsieve pores arranged side by side) was also used in this work. The DCB diazonium salt and AAOT alkaline solutions were dispersed into the microchannel by two microsieve pores (in Figure 5, feed pipe 1,3).…”

Revisiting aromatic diazotization and aryl diazonium salts in continuous flow: highlighted research during 2001–2021

“…7). 83,84 Their work shows that reducing the mass transfer distance, increasing the flow rate and improving the concentration distribution are important means of enhancing the mass transfer, and port improvement in the micromixer can prevent clogging.…”