Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb2O5-SiO2-coated magnetic nanoparticles

Abstract

A series of Nb (3 wt% or 60 wt% Nb2O5)-based magnetic nanocomposites (Nb-Si@MNP) was prepared by covering the magnetic cores with Nb2O5-SiO2 shells using either co-precipitation or sol-gel followed by precipitation methods. These materials were exhaustively characterized through XRD, Raman spectroscopy, CO2- and NH3-TPD, DRIFT spectroscopy, and TG-DTA, after which the catalytic one-pot conversion of cellulose to valuable α-hydroxy-acids (i.e. lactic and glycolic acids) was investigated. The catalytic performances, expressed in terms of lactic and glycolic acid yields, were directly correlated to the nature of the catalytic sites which, in turn, depended on the niobia content and the preparation route.

Keywords

• cellulose
• composite
• glycolic acid
• lactic acid
• magnetic nanoparticles
• niobia-silica