Polymeric Ionic Liquid: An Efficient Homogeneous Catalyst for Production of 5‐HMF in a Plug Flow Reactor

ABSTRACT 5‐Hydroxymethylfurfural (5‐HMF) is an impending molecule that can be produced from biomass‐derived hexose sugars and has several potential applications. The present manuscript demonstrates the exploration of the polyethyleneimine‐functionalized polymeric protic ionic liquid‐1 (PolyE‐IL‐1) catalyst for fructose dehydration into 5‐HMF in the presence of isopropyl alcohol (IPA) as a green solvent with high yield efficiency and selectivity in a continuous reactor system. The advantages of using this specific catalyst, such as high 5‐HMF yield and selectivity, easy catalyst separation, reusability, and recyclability, make it a promising option for various applications that utilize 5‐HMF as a platform molecule. A continuous reactor system, plug flow recycle reactor (PFRR), was designed and fabricated with a reactor volume of ≈54 mL. Further, process intensification studies were conducted to obtain the maximum yield, conversion, and selectivity. Approximately four recycle passes are required to achieve maximum conversion (≈82%), with (≈75%) 5‐HMF yield and (≈91%) selectivity at the optimized volumetric flow rate of 6 mL min −1 and residence time of 208 min (≈3.5 h). As a result, the optimized process offers high yields (75%), conversion (82%), and selectivity (91%) in PFRR, making it a promising and sustainable method for production of 5‐HMF from bio‐based hexose sugars.