Reductive amination of levulinic acid to N-substituted pyrrolidones over RuCl3 metal ion anchored in ionic liquid immobilized on graphene oxide

Abstract

Reductive amination of biomass derived Levulinic acid (LA) for the synthesis of N-substituted pyrrolidones is one of the highly attractive routes for biomass valorization. The supported homogeneous metal precursor into the solid surface is an important context in the field of catalysis because these types of catalysts provide the heterogeneous nature and meet the needs of recyclability. Herein, we have reported a synthesis of catalyst with ruthenium ion supported on ionic liquid immobilized into graphene oxide (Ru@GOIL) and its application for reductive amination reaction. Synthesized catalyst is characterized using different analytical techniques such as FT-IR, XRD, XPS, TGA, FEG-SEM, TEM and EXAFS analysis. The prepared Ru@GOIL found to be highly effective for reductive amination of LA and under these optimized conditions various N-substituted pyrrolidones derivatives were synthesized in excellent yield (78–93%). Ru@GOIL catalyst demonstrated great catalytic performance for reductive amination reaction of LA giving good turnover frequency (TOF = 62 h−1) value in comparison with other catalysts. The Ru@GOIL catalyst was recycled for six reaction runs with slight drop-in activity after 4th cycle. Practical applicability of the developed catalyst was successfully demonstrated by direct transformation of biomass waste (rice husk and wheat straw) derived LA to N-substituted pyrrolidones.