Electrocatalytic Hydrogenation and Deoxygenation of Glucose on Solid Metal Electrodes

Abstract

This Full Paper addresses the electrocatalytic hydrogenation of glucose to sorbitol or 2-deoxysorbitol on solid metal electrodes in neutral media. Combining voltammetry and online product analysis with high-performance liquid chromatography (HPLC), provides both qualitative and quantitative information regarding the reaction products as a function of potential. Three groups of catalysts clearly show affinities toward: (1) hydrogen formation [on early transition metals (Ti, V, Cr, Mn, Zr, Nb, Mo, Hf, Ta, We, and Re) and platinum group metals (Ru, Rh, Ir, and Pt)], (2) sorbitol formation [on late transition metals (Fe, Co, Ni, Cu, Pd, Au, and Ag) and Al (sp metal)], and (3) sorbitol and 2-deoxysorbitol formation [on post-transition metals (In, Sn, Sb, Pb, and Bi), as well as Zn and Cd (d metals)]. Ni shows the lowest overpotential for the onset of sorbitol formation (-0.25 V) whereas Pb generates sorbitol with the highest yield (<0.7 mM cm(-2) ). Different from a smooth Pt electrode, a large-surface-area Pt/C electrode hydrogenates glucose to sorbitol from -0.21 V with relatively low current. This emphasizes the importance of the active sites and the surface area of the catalyst. The mechanism to form 2-deoxysorbitol from glucose and/or fructose is discussed according to the observed reaction products. The yield and selectivity of hydrogenated products are highly sensitive to the chemical nature and state of the catalyst surface.

Hydroxyacetone: A Glycerol‐Based Platform for Electrocatalytic Hydrogenation and Hydrodeoxygenation Processes

“…It seems that the hydroxyl group in alpha-hydroxy ketones (such as hydroxyacetone) is alwaysp referred to be reduced at electrodes that would normally reduce the ketone group-a peculiar behaviort hat has already been described by Kwon et al [15] The reduction thus does not lead to 1-propanol butt oa cetone. It seems that the hydroxyl group in alpha-hydroxy ketones (such as hydroxyacetone) is alwaysp referred to be reduced at electrodes that would normally reduce the ketone group-a peculiar behaviort hat has already been described by Kwon et al [15] The reduction thus does not lead to 1-propanol butt oa cetone.…”

“…1-Propanol was detected only in trace amounts. It seems that the hydroxyl group in alpha-hydroxy ketones (such as hydroxyacetone) is alwaysp referred to be reduced at electrodes that would normally reduce the ketone group-a peculiar behaviort hat has already been described by Kwon et al [15] The reduction thus does not lead to 1-propanol butt oa cetone. Trace amountso f1 -propanol are most likely caused by the Lobry de Bruyn-Alberda van Ekenstein transformation [16] (LdB-AvE, Scheme 3) of acetol to 2-hydroxypropanal.…”

Electrochemistry for the Generation of Renewable Chemicals: One‐Pot Electrochemical Deoxygenation of Xylose to δ‐Valerolactone

“…[32][33][34] However,t he direct reduction of an ormal hydroxyl group and ac arboxylic group is electrochemically inaccessible in aqueous media. The exploitation of Clemenson-type cathodic reductions of aldehyde and ketone groups is well documented.…”

“…Also, hydroxyl group(s)a ta-position(s) to ac arbonyl group can be converted to methylene bridges. [32][33][34] However,t he direct reduction of an ormal hydroxyl group and ac arboxylic group is electrochemically inaccessible in aqueous media. Consequently,t he level of deoxygenation that can be achieved for ac arbohydrate substrate by direct cathodic reduction is limited.…”

Electrochemical Hydrogenation of Acetone to Produce Isopropanol Using a Polymer Electrolyte Membrane Reactor

“…ECH has been widely used to upgrade unsaturated compounds to corresponding saturated chemicals, such as furfural [14][15][16][17][18][19][20], aromatic compounds [7,13,[21][22][23][24][25][26][27][28][29], soybean oil [30], edible oil [31,32], levulinic acid [33][34][35], lactic acid [36], acetaldehyde [37], ethanol [37], acetylene [38], bio-oil [39,40], cyclohexane [9], glucose [41], and lignin [42]. In all those cases, reactions take place under mild conditions with temperatures below 100 • C and atmospheric pressure.…”