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

Abstract

A microbore tube is used to synthesize an imidazolium-based ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIM]Br) in continuous and solvent-free mode to achieve high space-time-yield and production rate while ensuring operation in kinetically controlled regime. Within the range of the experiments, product yield is found to increase with an increase in reaction temperature and residence time. Maximum values of space-time-yield and production rate achieved are 216gm/min-L and 1172gm/day, respectively. The effects of different parameters (design of the microfluidic junction, flow velocity, and the extent of coiling of the microbore tube) on the product yield and production rate are studied. Opposed T-junction is found to be better than cross T-junction. Product yield increases when flow velocity is increased keeping the residence time unchanged. Product yield is found to increase with reduction in coiling diameter. Though the use of a microbore tube ensures kinetically controlled regime, a few experiments are deliberately carried out in mass transfer controlled regime to understand the issues that become important in mass transfer controlled regime.