A Polyethylenimine‐Functionalized Protic Ionic Liquid (PolyE‐IL) Catalyst for Conversion of Aqueous 2,3‐Butanediol into Methyl Ethyl Ketone (MEK)

Abstract

AbstractThe dehydration of C6 sugars derived 2, 3‐butane diol (2, 3‐BDO) into Methyl Ethyl Ketone (MEK) is an emerging, and green alternative for production of green platform chemicals. In the present manuscript polyethyleneimine (PEI) functionalized protic ionic liquid (PolyE‐IL) has been integrated as a selective, recyclable, robust and efficient catalyst for dehydration of aqueous 2, 3‐BDO into MEK. The exploration of PolyE‐IL catalyst provides selective dehydration of aqueous 2,3‐BDO with significantly higher yield (>70 %) of MEK and conversion (>80 %) of 2,3‐BDO. PolyE‐ILs with different counter ions were synthesized and tested for 2,3‐BDO dehydration. Of the tested catalyst, PolyE‐IL‐1 with sulfonic acid counter ion ([PEI]+[HSO4]−) showed excellent performance for obtaining high MEK yield (77 %) and 2,3‐BDO conversion (85 %) at 220 °C. Moreover, the [PEI]+[HSO4]− catalyst showed excellent performance in term of TON (4.16) and TOF (0.14) with E‐Factor (0.33) and PMI (28.3). The recyclability study for five consecutive runs showed the consistency in yield (>70 %) and conversion (>80 %). Thus, PolyE‐IL catalyst found to be robust and stable under optimized reaction conditions. The present process provides several environmental and process economical benefits of low operating temperature, pressure, reaction time, and catalyst recycle. The use of PolyE‐IL shall contribute to development of economically and industrially feasible process.