Chitin-derived NC support vanadia as highly efficient catalyst for the oxidation of ethyl lactate to ethyl pyruvate

Abstract

Designing and synthesizing bio-based catalysts for the catalytic conversion of biomass to high-value chemicals is a green and promising route in the field of sustainable chemistry. Herein, V_xO_y/NC_P catalyst was synthesized by a simple impregnation-pyrolysis method using green and cheap bio-chitin or chitosan as the N-doped carbon (NC) precursor and was applied to the aerobic oxidation of ethyl lactate (EL) to ethyl pyruvate (EP). These catalysts were characterized by XRD, N₂ adsorption-desorption, SEM, TEM, XPS, and H₂-TPR. When chitin was used as the NC precursor (V_xO_y/NC_chitin), the catalyst activity was significantly higher than that of chitosan as the NC precursor (V_xO_y/NC_chitosan). Correlation between catalytic performance and characterization results showed that the high surface area, abundant pyridinic-N, and low valence vanadium species (V³⁺ and V⁴⁺) played an important role in catalyst activity. A 97.3 % EL conversion with 97.8 % EP selectivity was obtained over V_xO_y/NC_chitin at 120 °C for 2 h, and no significant deactivation after five cycles. Moreover, this catalyst also showed a high activity in the selective oxidation of other alcohols to their corresponding aldehydes.