Passive isothermalisation of an exothermic reaction in flow using a novel “Heat Pipe Oscillatory Baffled Reactor (HPOBR)”

Abstract

In this study, a heat pipe was integrated with a mesoscale oscillatory baffled reactor for the passive temperature control of an exothermic reaction. The thermal/chemical performance of this new Heat Pipe Oscillatory Baffled Reactor (HPOBR) was compared to a conventional jacketed OBR (JOBR) using central composite experiment designs for an imination reaction between benzaldehyde and n-butylamine, in the absence of solvent. The variables in the experimental designs were reactant net flow rate (Ren=4–20), fluid oscillation intensity (Reo=123–491) and heat pipe fill ratio (FR=11.5–26.5; methanol working fluid). In the JOBR, the fill ratio factor was replaced with jacket temperature (4–20°C). Both reactors were able to reduce the maximum reaction temperature below the butylamine boiling point in all experiments. Overall, a 20-fold reduction in reactant volume and 13-fold improvement in reaction rate were obtained in the HPOBR for this imination reaction, compared with the same reaction using a solvent. Advantages of the HPOBR demonstrated here are isothermal operation and passive thermal control. Both reactors offer accelerated reaction rates and the potential for screening exothermic reactions. The HPOBR is a novel reactor design that provides a new approach for achieving green chemistry through solventless operation.