A simple and efficient synthesis protocol for sulfonation of nitrobenzene under solvent-free conditions via a microreactor

Abstract

A simple and efficient method for the sulfonation of nitrobenzene using SO 3 as the sulfonating agent in a microreactor was developed and conducted in this work. The reaction enthalpy was determined using a microreactor-based calorimeter. The effects of molar ratio of reactants, reaction temperature and liquid hourly space velocity (LHSV) on the reaction performance were experimentally studied under solvent-free conditions. Under optimized reaction conditions, 94% conversion of nitrobenzene (NB) and 88% yield of meta-nitrobenzenesulfonic acid (m-NBSA) was obtained even when the residence time was less than 2 s. A microreactor-batch set-up was fabricated and developed to completely convert NB. The process safety has been improved and reaction time has been reduced compared to the batch method. These results demonstrate that the multifunctional integrated microreactor is an extremely useful and highly efficient tool for the sulfonation of NB under solvent-free conditions.

A peculiar segmented flow microfluidics for isoquercitrin biosynthesis based on coupling of reaction and separation

“…As shown in Table 2, the a-helix fraction was relatively lower in 4 than 2 lL/min flow rates in the segmented flow microreactor. This could be due to an accelerated extracted mass transfer and may be attributed to turbulence (Chen et al, 2012), which can induce structural transformations that may affect the enzyme active site. The b-sheet content in the segmented microreactor with the 4 lL/min flow rate was slightly higher than other flow rates, indicating that the tighter structure may have covered the activity center and thereby hindered the reactants from reaching the enzyme active site.…”

Aromatic sulfonation with sulfur trioxide: mechanism and kinetic model

“… 3 – 5 The most commonly used sulfonating agents are sulfur trioxide (SO 3 ), oleum, sulfuric acid and chlorosulfuric acid. 6 …”

Characterization of liquid–liquid mass transfer performance in a capillary microreactor system

“…Many liquid‐liquid heterogeneous processes such as reactive extraction, oxidation, nitration, sulfonation, and emulsion polymerization are kinetically fast and thus their process efficiencies strongly depend on the heat and mass transfer performance in reactors. The hydrodynamics, mass transfer and reaction processes of liquid–liquid heterogeneous systems in microreactors have been widely studied .…”