In-Situ Investigations of Polyoxometalate-Catalysed Biomass Oxidation to Formic Acid by Using Multinuclear High Resolution Flow NMR Spectroscopy

ChemCatChem Supporting Information In-Situ Investigations of Polyoxometalate-Catalysed Biomass Oxidation to Formic Acid by Using Multinuclear High Resolution Flow NMR Spectroscopy Jan-Dominik H. Krueger, Maximilian J. Poller, Catherine Lyall, John Lowe, Ulrich Hintermair,* and Jakob Albert* Wiley VCH Dienstag, 07.05.2024 2499 / 351570 [S. 15/15] 1 In-situ investigations of polyoxometalate-catalysed biomass oxidation to formic acid using multinuclear highresolution FlowNMR Spectroscopy Jan-Dominik H. Krueger1, Maximilian J. Poller1, Catherine Lyall2, John Lowe2, Ulrich Hintermair*2, Jakob Albert*1 1 Institute of Technical and Macromolecular Chemistry, Universität Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany 2 Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, United Kingdom * u.hinterm[email protected], [email protected] Supplementary Information Table of Contents Experimental setup: 10-fold screening plant (UHH) 2 Experimental setup: FlowNMR plant (UB) 2 Catalyst characterization: 3 IR-spectroscopy 3 NMR-spectroscopy 4 Preliminary catalytic experiments in batch mode (10-fold screening plant) 6 Substrate selection 6 Substrate concentration selection 7 Variation of selectivity enhancing additive 7 Variation of rate enhancing additive 8 Catalytic experiments in FlowNMR 9 Aqueous oxidation of GA with HPA-2 (no additives) 9 Aqueous oxidation of GA with HPA-2 with 10 vol.% MeOH added (selectivity enhancing) 10 Aqueous oxidation of GA with HPA-2 with oxalic acid added (rate enhancing) 12 Stability test of internal Standard tert-Butanol: 13 Influence of formic acid on pH value of reaction solution: 13 This document contains 7 Tables and 17 Figures on 14 pages. Experimental setup: 10-fold screening batch plant (UHH) Figure S1: Process flow diagram of the high-pressure tenfold screening plant. Experimental setup: FlowNMR plant (UB) Figure S2: Process flow diagram of the FlowNMR-setup in Bath. [React. Chem. Eng., 2021, 6, 1548-1573] Catalyst characterization: FTIR-spectroscopy Figure S3: IR spectrum of HPA-2. Keggin-Structure type can be confirmed. NMR-spectroscopy Figure S4: 51V-NMR Spectrum of HPA-2. Solvent H2O, T = 298 K, Bruker 500 MHz @Dream facility. Figure S5: 31P-NMR spectrum of HPA-2. Solvent H2O, T = 298 K, Bruker 500 MHz @Dream facility. Figure S6: T1-Delay measurement of used catalyst. Solvent D2O, T = 350 K, Bruker 500 MHz @Dream facility. Figure S7: integrated values for T1-time determination of used catalyst. Integrals corresponding do colours shown in Figure S6. Table S1: T1-time results for different catalyst isomers. Signal Y – H4PVMo11O40 Y1 - α-1,4 Y2 - α-1,4 Y3 – higher substituted species T1 time (ms) 31.5 8.6 10.6 6.3 Preliminary catalytic experiments in batch mode (10-fold screening plant) Substrate selection Table S2: Preliminary experiments for substrate selection in ten-fold screening plant. Conversion (X) and yields (Y) of model substrates screening as determined by HPLC- (liquid phase products) and GC-Analysis (gas phase products). substrate Xsubstrate [%] Yformic acid [%] Ycarbon dioxide [%] ethylene glycol (C2H6O2) 3.0 0.0 2.2 glycol aldehyde (C2H4O2) 33.0 29.2 5.9 glycolic acid (C2H4O3) 13.2 1.5 9.9 glyoxal (C2H2O2) 100 75.0 11.9 glyoxylic acid (C2H2O3) 100 50.0 50.0 Reaction conditions: c(substrate) = 10 mmol/L, c(catalyst) = 10 mmol/L, T = 70 °C, t = 4 h, pO2 = 5 bar, solvent = water. Variation of substrate concentration Table S3: Preliminary experiments for substrate concentration selection in ten-fold screening plant. Conversion (X) and yields (Y) of model substrates screening as determined by HPLC- (liquid phase products) and GC-Analysis (gas phase products). Glycol aldehyde Concentration Catalyst (concentration) Xsubstrate [%] Yformic acid [%] Ycarbon dioxide [%] 100 mmol/L - 2 0 0 300 mmol/L HPA-2 (10 mmol/L) 52 47.0 5.1 100 mmol/L HPA-2 (10 mmol/L) 57 51.0 7.1 50 mmol/L HPA-2 (10 mmol/L) 57 52.0 9.7 10 mmol/L HPA-2 (10 mmol/L) 59 50.0 13.2 Reaction conditions: T = 80 °C, t = 3 h, pO2 = 5 bar, solvent composition = 100 % water. Variation of selectivity enhancing additive Table S4: Preliminary experiments for variation of selectivity enhancing additive in ten-fold screening plant. Conversion (X) and yields (Y) of model substrates screening as determined by HPLC- (substrate conversion), 1H-NMR- (liquid phase products) and GC-Analysis (gas phase products). Variation of solvent additive Xsubstrate [%] YC1 building block [%] Ycarbon dioxide [%] none 57 51.96 9.66 2 vol.% MeOH 40 30.00 2.05 10 vol.% MeOH 30 29.54 1.44 2 vol.% EtOH 40 30.03 2.08 10 vol.% EtOH 40 29.2 1.10 2 vol.% iPrOH 22 20.05 1.04 10 vol.% iPrOH 19 17.5 0.99 none 57 51.96 9.66 Reaction conditions: T = 80 °C, t = 3 h, pO2 = 5 bar, solvent composition = 100 % water or – vol.% as noted, catalyst: HPA ‑ 2 (10 mmol/L), c(glycolaldehyde) = 50 mmol/L. Variation of rate enhancing additive Table S5: Preliminary experiments for variation of rate enhancing additives in ten-fold screening plant. Conversion (X) and yields (Y) of model substrates as determined by HPLC- (substrate conversion), 1H-NMR- (liquid phase products) and GCanalysis (gas phase products). Variation of reactive additive Xsubstrate [%] YCombined formic acid and formate [%] Ycarbon dioxide [%] None (pure water) 79 65.8 9.11 With 10 vol.% MeOH 80 71 1.40 With acetic acid 86 69 10.95 Acetic acid and 10 vol.% MeOH 83 74 0.63 With oxalic acid 97 79.30 14.92 Oxalic acid and 10 vol.% MeOH 100 88 4.85 Reaction conditions: T = 80 °C, t = 3 h, pO2 = 5 bar, solvent composition = 100 % water.