Effect of distribution of phase transfer catalysts in the microreactor shells on the catalytic oxidation of dibenzothiophene

• The main virtue of microreactors is high surface area and loaded amount of catalyst.
• The microreactors have porous microgels core and phase transfer catalysts shell.
• The core stores oxidant (H2O2), and the shell is amphiphilic and catalytic.
• The microreactors make integration of reactor and extractor into one system.
• The catalyst showed good catalytic performance and reusability.

Two kinds of microreactors using the porous and imperforate poly(acrylamide-co-methacrylic acid) (P(AM-co-MAA)) microgels as cores and the phase transfer catalysts (the complex between 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride (AEM) and K2{W(O)(O2)2 (H2O)}2 (W2)) as shell, were respectively prepared. The prepared microreactors were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and energy-dispersive X-ray spectrophotometer (EDX). The results indicated that the P(AM-co-MAA)/AEM/W2 microreactor with porous core has the turtle shell-like surface but that with imperforate core has smooth surface. The following results regarding the oxidation of dibenzothiophene (DBT) catalyzed by the two kinds of microreactors were obtained. Although amount of phase transfer catalysts loaded in the microreactors with the turtle shell-like surface is obviously higher than that of the microreactors with smooth surface, the catalytic efficiency of the microreactors with the turtle shell-like surface is obviously lower than that of the microreactors with smooth surface. The results imply that the effect of the distribution of phase transfer catalysts in the core–shell microreactors on the catalytic efficiency is more remarkable than that of the loaded amount of catalysts.

SEM images of P(AM-co-MAA) microspheres (a), P(AM-co-MAA)/AEM/W2 microreactors (b) and fourth run recovered microreactors (c). Step I: P(AM-co-MAA)/AEM/W2 microreactors were prepared by hydrolysis- condensation and ion-exchange reaction. Step II: the recovered microreactors were easily obtained by washing and drying.Figure optionsDownload as PowerPoint slide