Aerobic oxidation of 5-(hydroxymethyl)furfural into 2,5-diformylfuran catalyzed by starch supported aluminum nitrate

The untold story of starch as a catalyst for organic reactions

Starch is one of the members of the polysaccharide family. This biopolymer has shown many potential applications in different fields such as catalytic reactions, water treatment, packaging, and food industries. In recent years, using starch as a catalyst has attracted much attention. From a catalytic point of view, starch can be used in organic chemistry reactions as a catalyst or catalyst support. Reports show that as a catalyst, simple starch can promote many heterocyclic compound reactions. On the other hand, functionalized starch is not only capable of advancing the synthesis of heterocycles but also is a good candidate catalyst for other reactions including oxidation and coupling reactions. This review tries to provide a fair survey of published organic reactions which include using starch as a catalyst or a part of the main catalyst. Therefore, the other types of starch applications are not the subject of this review.

Recent Approaches in the Catalytic Transformation of Biomass-Derived 5-Hydroxymethylfurfural into 2,5-Diformylfuran

The conversion of biomass into a great variety of valuable chemicals, polymers, and fuels gives a sustainable alternative for the insufficiency of non-renewable fossil fuel resources and reduces environmental pollution. 5-Hydroxymethylfurfural (HMF), converted from sustainable carbohydrates, is a significant building block chemical, and the selective oxidation of HMF into 2,5-diformylfuran (DFF) presents an ongoing challenge. DFF is a versatile platform molecule derived from biomass and has promising application in pharmaceuticals and polymers. This Review provides an overview of the latest developments of efficient catalytic systems for the sustainable conversion of HMF to DFF.

Advances of Ionic Liquids and Deep Eutectic Solvents in Green Processes of Biomass-Derived 5-Hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF) is identified as an important bio-based platform chemical to bridge petroleum-based and biomass-based resources. It can be obtained through dehydration of various carbohydrates as well as converted to value-added fuels and chemicals. As designer solvents, ionic liquids (ILs) and deep eutectic solvents (DESs) have been widely used in catalytic transformation of biomass derivatives to various chemicals. This Review summarizes recent progress in experimental and theoretical studies on dehydration of carbohydrates such as fructose, glucose, sucrose, cellobiose, chitosan, cellulose, inulin, and even raw biomass to generate HMF using ILs and DESs as catalysts/cocatalysts and/or solvents/cosolvents. It also gives an overview of IL and DES-involved catalytic transformation of HMF to downstream products via oxidation, reduction, esterification, decarboxylation, and so forth. Challenges and prospects of ILs and DESs are also proposed for further production of HMF and HMF derivatives from biomass in green and sustainable processes.

Production of the 2,5-Furandicarboxylic Acid Bio-Monomer From 5-Hydroxymethylfurfural Over a Molybdenum-Vanadium Oxide Catalyst

2, 5-Furandicarboxylic acid (FDCA) is an important bio-monomer that can potentially replace terephthalic acid to synthesize degradable polyesters. Efficient selective oxidation of biomass-based 5-hydroxymethylfurfural (HMF) to FDCA has been a significant but challenging work in the past decades. In this study, a novel molybdenum-vanadium oxide (Mo-V-O) catalyst was prepared by a simple method and showed excellent catalytic activity for converting HMF to FDCA. A high FDCA selectivity of 94.5 and 98.2% conversion of HMF were achieved under the optimal conditions with tert-butyl hydroperoxide as the oxidant. FT-IR, SEM, XRD and TG were applied to investigate the properties of Mo-V-O catalyst. After fitting experimental data with the first-order kinetics equation, the evaluated apparent activation energies of HMF oxidation were obtained. The experimental design and study were carried out by response surface methodology (RSM) to test the effects of reaction conditions on the catalytic process.

Novel cellulose supported 1,2-bis(4-aminophenylthio)ethane Ni(ii) complex (NiII(BAPTE)(NO3)2-Cell) as an efficient nanocatalyst for the synthesis of spirooxindole derivatives

Cellulose was used as a support for immobilizing a Ni(ii) complex of 1,2-bis(4-aminophenylthio)ethane to prepare NiII(BAPTE)(NO3)2-Cell as a new organo-inorganic hybrid nanocatalyst. The properties of the prepared catalyst were studied using various analyses such as FT-IR, XRD, SEM, TGA and EDX. NiII(BAPTE)(NO3)2-Cell was employed as a reusable catalyst for the synthesis of spirooxindole derivatives via a three-component condensation of isatin, malononitrile and reactive methylene compounds. The nanocatalyst can be readily and quickly separated from the reaction mixture and can be reused for at least eight successive reaction cycles without a significant reduction in efficiency. The facile accessibility to the starting materials, use of green solvents and conducting the reactions in eco-friendly and cost-effective conditions have made this protocol a suitable method for preparing spirooxindole derivatives.

Ultrafine Copper Oxide Particles Dispersed on Nitrogen-Doped Hollow Carbon Nanospheres for Oxidative Esterification of Biomass-Derived 5-Hydroxymethylfurfural

One-pot synthesis of furan-2,5-dimethylcarboxylate (FDMC) from 5-hydroxymethylfurfural (HMF) is highly demanding for the commercial production of polyethylene furanoate (PEF). Herein, a direct synthesis of FDMC is reported from oxidative esterification of HMF using ultrafine CuO particles dispersed on nitrogen-doped hollow carbon nanospheres (CuO/N-C-HNSs) as a catalyst and tert-butyl hydroperoxide (TBHP) as an oxidizing and methylating reagent. The CuO/N-C-HNSs was prepared through a template protection-sacrifice strategy using SiO₂ as a sacrificial template and histidine as the precursor for N and C. N-doping facilitated a strong interaction between the support and copper species, affording formation of CuO nanoparticles of less than 10 nm in size. By virtue of the highly dispersed CuO nanoparticles and a high BET surface area 373 m² /g, the CuO/N-C-HNSsshows excellent catalytic performance in the selective conversion of HMF into FDMC affording 93 % yield of the desired product with a TON value of 49. Furthermore, the oxidative esterification involving SP³ C-H bond functionalization is also demonstrated using the same catalyst.

A gram scale selective oxidation of 5-hydroxymethylfurfural to diformylfuran in the presence of oxone and catalyzed by 2-iodobenzenesulfonic acid

In the present work, an alternative system of 5-hydroxymethylfurfural (HMF) oxidation was studied, in an attempt to avoid the use of expensive metal catalysts, polluting systems and high pressures.