On continuous, solvent-free synthesis of ionic liquid [BMIM]Br in a microbore tube

Abstract

Synthesis of an imidazolium-based ionic liquid (IL) 1-butyl-3-methylimidazolium bromide, a precursor to hydrophobic ILs having potential applications in nuclear fuel cycle, is carried out in a microbore tube in solvent-free and continuous mode. Product yield increased monotonically with increasing reaction temperature and residence time. Space-time-yield (STY) and production rate decreased with increase in residence time and increased with increase in reaction temperature. Maximum values of STY and production rate achieved are 131.5 g/min l and 278 g/day, respectively. Experimental data suggest that the reaction, when carried out in a microbore tube, is kinetically controlled. Flow patterns inside the microbore tube, observed using a high speed imaging system, also suggest the same.

Liquid–Liquid Two-Phase Flow Patterns in Y-Junction Microchannels

“…There are several advantages of using microchannels for carrying out unit operations and unit processes. High surface to volume ratios of microchannels ensure intensified heat transfer, making microchannels very attractive for carrying out highly exothermic reactions. − Smaller inventories in microchannels make them suitable for processes involving hazardous chemicals. − Also, scale-up of processes based on microchannels is easier due to the numbering-up approach followed for scale-up. − Due to the above advantages, microchannels are being explored for diverse applications in chemical engineering including processes based on multiphase flow . One of such applications is solvent extraction. − The small flow cross-section of a microchannel ensures a large specific interfacial area and large overall volumetric mass transfer coefficient which eventually lead to intensification of mass transfer. − …”

Study on Interfacial Mass Transport and Process Intensification for Ionic Liquid [BMIM]Br Synthesis

“…Motivated by the intensification of interfacial mass transfer during the synthesis of MIM-based ILs, we experimentally investigate the evolution of the droplets during the synthesis of ILs. In the present work, [BMIM]Br was chosen as a representative MIM-based ILs since [BMIM]Br can be regarded as the source of many other ILs 33 and the synthesis reaction of [BMIM]Br has typical characteristics in reaction progress and interfacial mass transfer. Based on the characteristics of the droplet behavior, intensification strategies for the reaction process are proposed.…”

Model-based scale-up and reactor design for solvent-free synthesis of an ionic liquid in a millistructured flow reactor

“…[15][16][17][18] Recently, micro process engineering has been used for synthesis of high-quality ionic liquids with increased spacetime yields and even solvent-free reactor operation. [19][20][21][22][23][24][25] Compared with conventional batch processes, the intensified transfer of heat and mass that occurs in microstructured devices offers two major advantages for solvent-free synthesis: first, the reaction heat of the strongly exothermic alkylation step (reaction enthalpy of approximately 100 kJ mol −1 ) can be rapidly removed. This is crucial because a large and uncontrolled increase in temperature reduces product quality by introducing color.…”

“…20,26 Second, microreactors facilitate handling of a dispersed product phase, which reportedly forms in several solvent-free ionic liquid syntheses. 19,21 In this contribution, we discuss process development for a solvent-free continuous synthesis of 1-butyl-3-methylimidazolium bromide ([BMIM]Br, Scheme 1). We aimed to develop a process with high productivity and maximum material efficiency.…”