Highly Efficient Oxidation of 5‐Hydroxymethylfurfural to 2, 5‐Furandicarboxylic Acid with Heteropoly Acids and Ionic Liquids. Issue 12 (20th May 2019) - Chen, Ruru
Abstract: 2, 5‐Furandicarboxylic acid (FDCA) is regarded as an important bioderived substitute for petrochemically derived terephthalic acid (PTA), which is widely applied in the polymer industry. This work delineates the base‐free oxidation of 5‐hydroxymethylfurfural (HMF) to FDCA in an ionic liquid/heteropoly acid (IL–HPA) catalytic system. HPAs displayed high activity for selective oxidation; their active center (Mo/V) was activated by O2 and transformed from oxygen single and double bonds to epoxy groups, resulting in an FDCA yield of 89 % for HPMV6 (HPM=H3 PMo12 O40 ) in the presence of [Bmim]Cl (1‐butyl‐3‐methylimidazolium chloride) under optimized reaction conditions. The high solubility of imidazole ILs for FDCA improved the affinity of HMF and the active centers of the catalyst and protected the furan ring from oxidative cleavage. Furthermore, multiple hydrogen bonds simultaneously formed between the electronegative anions and hydroxy protons of HMF, as well as the hydrogen atoms of the imidazole rings and hydroxy groups, promoting the transformation to aldehyde groups. Various starting materials were studied, and a moderate FDCA yield was obtained from glucose. This work provides an interesting IL–HPA catalytic system for the base‐free synthesis of FDCA from accessible monosaccharides and illustrates the great potential of FDCA production from renewable carbohydrates. Abstract : 2, 5‐Furandicarboxylic acid (FDCA), an important bioderived substitute for petrochemically derived terephthalic acid, is produced from 5‐hydroxymethylfurfural (HMF) through base‐free oxidation in an ionic liquid/heteropoly acid catalytic system. Over 99 % HMF conversion and 89 % FDCA yield are achieved at 140 °C in 6 h.