Experimental and CFD-assisted evaluation of isopropyl palmitate synthesis in a static-element microreactor

Isopropyl palmitate (IPP) is an ester widely used in personal care formulations. This study investigated its catalyst-free synthesis from palmitoyl chloride and isopropanol using computational fluid dynamics (CFD) and experiments in a 3D-printed PLA microreactor containing periodically arranged static elements. The CFD model represented a section of the complete 2632 μ L device and was used to assess hydrodynamics, species redistribution, reaction progress, volumetric productivity, and hydraulic demand. Reactive simulations were performed at 65 °C using a literature-derived second-order rate constant. Hydrogen chloride was represented as a pseudo-dissolved numerical species to close the stoichiometric mass balance, whereas gas–liquid partitioning was not modeled. Experimentally, temperature and nominal space time were evaluated using a 2² factorial design with triplicate center points. The CFD results showed repeated stream redistribution around the static elements and progressive attenuation of palmitoyl chloride-rich regions along the modeled section. Increasing the prescribed CFD space time increased predicted conversion and reduced pressure drop and hydraulic power, whereas the associated decrease in flow rate reduced volumetric productivity. At 65 °C and a nominal experimental space time of 15 min, the microreactor achieved an apparent conversion of 76.3%, compared with 56.1 ± 3.2% in the batch system, corresponding to approximately 36% on a relative basis. Although the unreplicated microreactor condition and the hydrodynamic differences between the reduced CFD domain and the complete reactor prevented statistical inference and formal numerical–experimental validation, the combined results showed how static elements redistribute the reactant streams and identified the trade-off among conversion, productivity, and hydraulic demand. This integrated assessment provides a mechanistic basis for reaction-specific reactor optimization and supports continuous-flow processing with static elements as a promising catalyst-free route to IPP.