Continuous flow rare earth phenolates catalyzed chemoselective ring-opening polymerization

Continuous Differential Microemulsion Polymerization to Prepare Nanosized Polymer Latices in Microreactors

Microreactors are a promising platform for continuous synthesis of polymer latices when combined with emulsion polymerization. However, this application has long been haunted by fouling and clogging problems. In this work, we proposed the strategy of conducting differential microemulsion polymerization in microreactors within a biphasic slug flow and achieved rapid and stable preparation of nanosized PMMA latices (polymeric content as high as 15.7% with average particle size smaller than 20 nm). We started by exploring the temperature thresholds with thermal and redox initiation, the effect of initiator concentration, and the kinetic characteristics of microemulsion polymerization at different temperatures. Then, as for the differential microemulsion polymerization, extensive investigation was made into the effects of the volumetric flow ratio, the prepolymerization time, the initiator concentration, and the solid content of the initial microemulsion. Finally, we compared the differential microemulsion polymerization with the soap-free emulsion polymerization in the slug flow. The striking advantages in the polymerization rate, the average particle diameter, and the size distribution reflected higher density of particle nuclei, larger specific surface area of particles, and the pivotal effect of the persistent particle nucleation in the microemulsion polymerization.

An application of continuous flow microreactor in the synthesis and extraction of rabeprazole

The oxidation of rabeprazole sulfide is a key step in the synthesis of rabeprazole, a drug for the treatment of stomach acid-related disorders. The current rabeprazole production process adopts one pot batch process, which has low reaction efficiency and poor stability. A continuous process can greatly improve the production efficiency and solve the above problems. Therefore, the reaction parameters of rabeprazole in microreactor were explored through laboratory experiments to explore the possibility of continuous production of rabeprazole. Rabeprazole sodium was synthesized by using rabeprazole thioether as a raw material and sodium hypochlorite solution as the oxidant. Oxidation, quenching, acid-base regulation and extraction were completed continuously in the microreactor. Rabeprazole solution with a purity of 98.78% (±0.13%) can be obtained continuously in 56 s, whereas intermittent production lasted for at least 2 h. Thus, the microreactor can effectively improve the oxidation synthesis efficiency of rabeprazole, and provide reference for the realization of other reactions in the microreactor.

Protecting-group-free synthesis of thiol-functionalized degradable polyesters

Protecting-group-free synthesis of thiol-functionalized degradable polyesters has been developed by using chemoselective catalysis and microflow technology.