Selective Production of Glycolic Acid from Cellulose Promoted by Acidic/Redox Polyoxometalates via Oxidative Hydrolysis

ACS Catalysis, vol. 13, pp. 4575–4586

Abstract

The direct conversion of cellulose to glycolic acid (GA) with a high yield of up to 75% is realized using acidic/redox polyoxometalates (POMs) as catalysts in a one-pot reaction. Analysis of the reaction pathway and mechanism for the three POMs H 3 PMo 12 O 40 (H 3 PMo), H 3 PW 12 O 40 (H 3 PW), and H 5 PMo 10 V 2 O 40 (H 5 PMoV 2 ) by density functional theory calculations and experiments shows that H 3 PMo is especially promising. Activation of O 2 to • O 2 – and 1 O 2 via one-electron transfer assists the depolymerization process of cellulose by acidic/redox H 3 PMo. The reduced form [PMo 10 VI Mo 2 V O 39 ] 5– plays a crucial role in GA production due to its high activity and ability to stabilize the intermediates of the retro-aldol reaction. H 3 PMo was furthermore complexed by the ionic liquid 1-(3-sulfonic group) propyl-3-methyl imidazolium (MIMPS), which enables easy recovery from the reaction solution due to temperature-responsive properties of the complexes. [MIMPS]H 2 PMo provides an outstanding GA selectivity of 61% under aerobic conditions and is comparable to the homogeneous H 3 PMo. Activity and selectivity to GA could be improved to 100 and 75%, respectively, by performing the reaction in the microwave at 190 °C for 2 min. The work deepens the insight on cellulosic biomass transformation over POMs by acidic/oxidative synergetic catalysis and contributes to the effort of designing highly active, selective, and multifunctional catalysts.

Authors 8

1. Zonghang Li

   Northeast Normal University

   Affiliation as printed

   Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China

2. Qiwen Wang

   Northeast Normal University

   Affiliation as printed

   Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China

3. Yiming Li

   Northeast Normal University

   Affiliation as printed

   Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China

4. Diantao Li

   Beihua University

   Affiliation as printed

   Department of Chemistry, Faculty of Science, Beihua University, Jilin City 132013, P. R. China

5. Regina Palkovits Aachen Institute of Technical and Macromolecular Chemistry

   RWTH Aachen University · Max Planck Institute for Chemical Energy Conversion

   Affiliation as printed

   Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, Aachen 52074, Germany

   Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany

6. Anna Katharina Beine corresponding

   Max Planck Institute for Chemical Energy Conversion

   Affiliation as printed

   Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany

7. Chun‐Guang Liu corresponding

   Beihua University

   Affiliation as printed

   Department of Chemistry, Faculty of Science, Beihua University, Jilin City 132013, P. R. China

8. Xiaohong Wang corresponding

   Northeast Normal University

   Affiliation as printed

   Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China