Potassium hydroxide

Copper (II) acetate monohydrate (98%, Komponent-Reaktiv, Moscow, Russia), Copper (II) sulfate pentahydrate (98%, Ruskhim, Moscow, Russia) and Copper (II) chloride dihydrate (98%, Komponent-Reaktiv, Moscow, Russia) were used as precursors for ultrafine copper particle formation without any further purification. Potassium hydroxide (98%, Chimmed, Moscow, Russia), glycerol (≥99.3%, Komponent-Reaktiv, Moscow, Russia) and distilled water were used as reaction feeds. In addition, 1,2-Butanediol (98%, abcr, Karlsruhe, Germany) was used as the inner standard, and 1,2-propanediol (>99%, Carl Roth, Karlsruhe, Germany), ethylene glycol (≥99.5%, Komponent-Reaktiv, Moscow, Russia), DL-lactic acid in aqueous solution (80%, Komponent-Reaktiv, Moscow, Russia) and hydroxyacetol (technical, Acros organics, Austria) were used for the GC quantification method. Trimethylsilylating reagent TMS-HT (hexamethyldisilazane + trimethylchlorosilane in anhydrous pyridine; abcr, Karlsruhe, Germany) was used for derivatization. For all hydrogenation processes, hydrogen gas (grade A in accordance with GOST 3022-80, MGPZ, Moscow, Russia) was used. For comparison purposes, a commercial copper chromite catalyst, VNH-103 (Vniineftekhim-103), that contained approximately 56% copper was used. The catalyst was reduced in hydrogen flow (10 vol % H₂/Ar, 6 h at 300 °C) before use.

The following materials and reagents were used: Nafion^® 212 membrane (equivalent weight 1100, The Chemours Company, Wilmington, DE, USA), N-methyl-2-pyrrolidone (Merck, Darmstadt, Germany), N,N-dimethylformamide (special purity, Chimmed, Moscow, Russia), ethylene glycol (special purity, Chimmed, Moscow, Russia), isopropyl alcohol (special purity, Chimmed, Moscow, Russia), lithium hydroxide (LiOH, ≥99.0%, Sigma-Aldrich, St. Louis, MO, USA), hydrochloric acid (special purity, 35–38%, Chimmed, Moscow, Russia), potassium chloride (reagent grade, Chimmed, Moscow, Russia), potassium hydroxide (reagent grade, Chimmed, Moscow, Russia); deionized water (resistance 18.2 MOhm).

The following reagents were used: N-methyl-2-pyrollidone (NMP) (Merck, Darmstadt, Germany), isopropyl alcohol (IPA) (special purity, Chimmed, Moscow, Russia), lithium hydroxide (≥99.0%, Sigma Aldrich, St. Louis, MO, USA), hydrochloric acid (special purity, 35–38%, Chimmed, Moscow, Russia), nitric acid (special purity, 60%, Chimmed, Moscow, Russia), hydrogen peroxide special (purity, 30%, Chimmed, Moscow, Russia), potassium chloride (reagent grade, Chimmed, Moscow, Russia), potassium hydroxide (reagent grade, Chimmed, Moscow, Russia), sodium chloride (reagent grade, Chimmed, Moscow, Russia), calcium chloride (reagent grade, Chimmed, Moscow, Russia), sodium bicarbonate (reagent grade, Chimmed, Moscow, Russia), N-acetyl-L-methionine (AM) (99%, J&K Scientific, San Jose, CA, USA), L-carnitine (CT) (>98%, Alfa Aesar, Haverhill, MA, USA), L-lysine (LS) (>99%, Alfa Aesar, Haverhill, MA, USA), deionized water (resistance 18.2 MOhm).
The membranes used were Nafion^® 212 (The Chemours Company, Wilmington, DE, USA) and Aquivion E87-05S (Solway, Brussels, Belgium). Nafion^® 212 film (The Chemours Company, Wilmington, DE, USA) and Aquivion PW79S powder (Solway, Brussels, Belgium) were used to obtain PFSA polymer dispersions. The main characteristics of the materials used are shown in Table 1.