Base-Free Selective Oxidation of Glycerol over LDH Hosted Transition Metal Complexes Using 3% H2O2 as Oxidant

Xiaoli Wang,Hao Liu,Congxiao Shang,Gongde Wu,Xianfeng Liu

doi:10.3390/catal6070101

Abstract

A series of transition metal sulphonato-Schiff base complexes were intercalated into Mg–Al layered-double hydroxides (LDHs). The obtained catalysts were characterized by FTIR, XRD, N2 sorption, SEM and elemental analysis, and then were used in the selective oxidation of glycerol (GLY) using 3% H2O2 as an oxidant. It was found that their catalytic performances were closely related to the loading of active complexes, the Schiff base ligands and the metal centers of the catalysts, as well as the reaction conditions. The optimal conversion of GLY was 85.0%, while the selectivity of 1,3-dihydroxyacetone (DHA) was 56.5%. Moreover, the catalysts could be reused at least 10 times.

Highlights

The use of biorenewable feedstocks to produce commodity chemicals and clean fuels as a substitute for the limited fossil fuel reserves is an essential pathway to sustainable development [1,2].In this context, the biodiesel industry was booming in the past decades
The results of elemental analysis revealed that the molar ratios of N to the transition metal in
layered-double hydroxides (LDHs)‐hosted complexes were in conformance with the calculated values according to

Summary

Introduction

The use of biorenewable feedstocks to produce commodity chemicals and clean fuels as a substitute for the limited fossil fuel reserves is an essential pathway to sustainable development [1,2]. There were many successful reports on the selective oxidation of GLY using noble metal catalysts [5,6,7,8,9,10,11,12]. It was of significance to design highly effective catalysts, especially a low-cost heterogeneous catalyst, for the oxidation reaction of GLY. LDH-hosted chromium complex, which was anwhich activewas catalyst for thecatalyst oxidation of GLY an LDH‐hosted chromium complex, an active for reaction the oxidation to DHA with. LDH-hosted chromium complexes chromium different base ligands, metal centerscomplexes Their catalytic performance was investigated extensively in the oxidation conversion performance was investigated extensively in the oxidation conversion of GLY using 3% H2 O2 asofan. Effect the the composition of the catalysts, and the oxidation reaction the oxidation on the catalytic performance of theincatalysts conditions on thereaction catalyticconditions performance of the catalysts was discussed detail. was discussed in detail

Characterization of Catalysts

Catalytic

Catalyst Preparation

Characterization

Catalytic Test

Conclusions