Production of 5-Hydroxymethyl-2-furan Carboxylic Acid Using Biobased Silver Nanoparticles in Deep Eutectic Substrate Reaction Mixtures

Abstract

Recently, the green synthesis of metal nanoparticles (NPs) using plant constituents and extracts has attracted much attention. Biologically active substances with antioxidant/reducing, nontoxic, low-cost properties and stabilizing agents are highly sought after. Among these substances, Stevia is a potentially interesting raw material for the preparation of biologically active extracts and the green synthesis of colloidal NPs. In our work, the synthesis of Ag NP colloids using Stevia plant leaf extracts was optimized. The synthesized Ag NPs were characterized by XRD, FE-SEM, TEM, HR-TEM, DLS, UV−vis, and XPS, and their performance as a cheap, biological, and available catalyst was evaluated for the selective synthesis of 5-hydroxymethyl-2-furan carboxylic acid (HMFCA) from the platform molecule 5hydroxymethylfurfural (5-HMF). In order to have a more sustainable process, this catalytic oxidation was carried out in various deep eutectic mixtures as a cool, green, and environmentally friendly reaction medium. The target molecule was obtained in an impressive 98% yield of HMFCA (45 min, 50 °C) and the Stevia-derived catalyst is easily removed from the reaction mixture and recycled up to six times without loss of activity.

Ag/GO/Fe3O4/γ-Fe2O3 Nanocomposite for Green-Light-Driven Photocatalytic Oxidation of 5-Hydroxymethylfurfural to 5-Hydroxymethyl-2-furancarboxylic Acid

“…By selective oxidation of the hydroxyl part, 2,5-diformylfuran (DFF) is obtained, and, by selective oxidation of the aldehyde part, 5-hydroxymethyl-2furancarboxylic acid (HMFCA), DFF, and 5-formyl acid-2furancarboxylic acid (FFCA) are formed. 44 There are only a few reports on the synthesis of HMFCA from the oxidation of HMF. In most cases, metal catalysts such as Pt/C, MnO 2 , and Au−Pd were used, and it often leads to low selectivity and consequently poor product yields.…”

“…As shown in Scheme , 5-HMF has a hydroxyl and aldehyde moiety. By selective oxidation of the hydroxyl part, 2,5-diformylfuran (DFF) is obtained, and, by selective oxidation of the aldehyde part, 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), DFF, and 5-formyl acid-2-furancarboxylic acid (FFCA) are formed …”