Efficient conversion of chitin biomass into 5-hydroxymethylfurfural over metal salts catalysts in dimethyl sulfoxide -water mixture under hydrothermal conditions

Progress in Catalytic Conversion of Renewable Chitin Biomass to Furan-Derived Platform Compounds

Chitin is one of the most abundant biopolymers on Earth but under-utilized. The effective conversion of chitin biomass to useful chemicals is a promising strategy to make full use of chitin. Among chitin-derived compounds, some furan derivatives, typically 5-hydroxymethylfurfural and 3-acetamido-5-acetylfuran, have shown great potential as platform compounds in future industries. In this review, different catalytic systems for the synthesis of nitrogen-free 5-hydroxymethylfurfural and nitrogen-containing 3-acetamido-5-acetylfuran from chitin or its derivatives are summarized comparatively. Some efficient technologies for enhancing chitin biomass conversion have been introduced. Last but not least, future challenges are discussed to enable the production of valuable compounds from chitin biomass via greener processes.

Microwave-assisted catalytic conversion of chitin to 5-hydroxymethylfurfural using polyoxometalate as catalyst

The key challenges for converting chitin to 5-hydroxymethylfurfural (5-HMF) include the low 5-HMF yield. Moreover, the disadvantages of traditional acid–base catalysts including complex post-treatment processes, the production of by-products, and severe equipment corrosion also largely limit the large-scale conversion of chitin to 5-HMF. In this view, herein we have demonstrated a microwave aided efficient and green conversion of chitin to 5-HMF while using polyoxometalate (POM) as a catalyst and DMSO/water as solvent. Chitin treated with H₂SO₄ followed by ball-milling (chitin-H₂SO₄-BM) was selected as the starting compound for the conversion process. Four different POMs including H₃[PW₁₂O₄₀], H₃[PMo₁₂O₄₀], H₄[SiW₁₂O₄₀] and H₄[SiMo₁₂O₄₀] were used as catalysts. Various reaction parameters including reaction temperature, amount of catalyst, mass ratios of water/DMSO and reaction time have been investigated to optimize the 5-HMF conversion. The H₄[SiW₁₂O₄₀] catalyst exhibited the highest catalytic performance with 23.1% HMF yield at optimum operating conditions which is the highest among the literature for converting chitin to 5-HMF. Significantly, the disadvantages of the state of the art conversion routes described earlier can be overcome using POM-based catalysts, which makes the process more attractive to meet the ever-increasing energy demands, in addition to helping consume crustacean waste.

We have demonstrated an efficient conversion of chitin to 5-HMF using a microwave aided method while using polyoxometalate (POM) as catalyst and DMSO/water as solvent.

Magnesium Oxide-Catalyzed Conversion of Chitin to Lactic Acid

Although chitin, an N-acetyl-D-glucosamine polysaccharide, can be converted to valuable products by means of homogeneous catalysis, most of the chitin generated by food processing is treated as industrial waste. Thus, a method for converting this abundant source of biomass to useful chemicals, such as lactic acid, would be beneficial. In this study, we determined the catalytic activities of various metal oxides for chitin conversion at 533 K and found that MgO showed the highest activity for lactic acid production. X-ray diffraction analysis and thermogravimetry-differential thermal analysis showed that the MgO was transformed to Mg(OH)2 during chitin conversion. The highest yield of lactic acid (10.8 %) was obtained when the reaction was carried out for 6 h with 0.5 g of the MgO catalyst. The catalyst could be recovered as a solid residue after the reaction and reused twice with no decrease in the lactic acid yield.

Efficient conversion of N-acetyl-D-glucosamine into nitrogen-containing compound 3-acetamido-5-acetylfuran using amino acid ionic liquid as the recyclable catalyst

Chitin is the most widely distributed oceanic biomass resources. Its monomer unit, N-acetyl-_D-glucosamine (NAG), contains precious atomic nitrogen and represents a potential feedstock for the manufacture of regenerative organic nitrogen chemicals. Herein, the conversion of NAG to the platform chemical, 3-acetamido-5-acetylfuran (3A5AF), catalyzed by amino acid ionic liquids, was investigated. The reaction, catalyzed by a very small amount of glycine chloride ionic liquid without any additives, could yield 43.22% 3A5AF in 10 min. By adding CaCl₂, a higher yield up to 52.61% was obtained. This work demonstrated the conversion of chitin biomass to 3A5AF in higher yield without using a boron-based catalyst for the first time. Moreover, the ionic liquid catalyst exhibited excellent recyclability, and afforded 43.22-36.59% yield over during eight cycles. This research provides new and green procedures to convert shellfish fishery waste into value-added platform chemicals.

Use of Ionic Liquids in Chitin Biorefinery: A Systematic Review

Lignocellulosic biomass biorefinery is the most extensively investigated biorefinery model. At the same time, chitin, structurally similar to cellulose and the second most abundant polymer on Earth, represents a unique chemical structure that allows the direct manufacture of nitrogen-containing building blocks and intermediates, a goal not accomplishable using lignocellulosic biomass. However, the recovery, dissolution, and treatment of chitin was fairly challenging until the polymer's easy dissolution in ionic liquids (salts that are liquid at room temperature) was discovered. In this systematic review, we highlight recent developments in the processing of chitin, with a particular emphasis placed on methods conducted with the help of ionic liquids used as solvents, co-solvents, or catalysts. Such use of ionic liquids in the field of chemical transformations of chitin not only allows for shorter times and less harsh reaction conditions, but also results in different outcomes and higher product yields when compared with reactions conducted in "traditional" manner. Valorization of biomass in general, and chitin in particular, is a key enabling strategy of the circular economy, due to the importance of the sustainable production of biomass-based goods and chemicals and full chain resource efficiency. Economics is driven by the production of high-value chemicals or chemical intermediates from various biomasses, and chitinous biomass is a valuable potential resource. A fundamental "paradigm shift" will radically change the balance of oil-based chemicals to biopolymer-based chemicals, and chitin valorization is a necessary step aimed toward its full market competitiveness and flexibility.

Production of 5-Hydroxymethylfurfural from Chitin Biomass: A Review

Chitin biomass, a rich renewable resource, is the second most abundant natural polysaccharide after cellulose. Conversion of chitin biomass to high value-added chemicals can play a significant role in alleviating the global energy crisis and environmental pollution. In this review, the recent achievements in converting chitin biomass to high-value chemicals, such as 5-hydroxymethylfurfural (HMF), under different conditions using chitin, chitosan, glucosamine, and N-acetylglucosamine as raw materials are summarized. Related research on pretreatment technology of chitin biomass is also discussed. New approaches for transformation of chitin biomass to HMF are also proposed. This review promotes the development of industrial technologies for degradation of chitin biomass and preparation of HMF. It also provides insight into a sustainable future in terms of renewable resources.

Simultaneous pretreatment and hydrolysis of hardwood biomass species catalyzed by combination of modified activated carbon and ionic liquid in biphasic system

The study highlights one pot conversion of hardwood biomass into Total reducing sugars (TRS) and 5-Hydroxymethyl Furfural (5-HMF). Synergistic effect of dilute H₂SO₄ and ionic liquid in a reaction time of 60 min at 120 °C was examined. Hydrolysis of Catalpa (Catalpa Bignonioides), Indian Rosewood (Dalbergia Sissoo), Chinaberry (Melia Azedarach) and Babool (Acacia Nilotica) catalyzed by modified activated carbon leads to significant product yield. Maximum yield was obtained using Catalpa wood i.e. 92.67% TRS and 70.36% 5-HMF under optimized conditions. Biomass before and after pretreatment subjected to FT-IR, XRD and compositional analysis determined the structural changes. Further, the effect of electrolytes namely; AlCl₃, MgCl₂, NaCl and KCl were evaluated. Results revealed that using optimized concentration of each electrolyte promoted the conversion to 96.56% (TRS) and 86.23% (5-HMF) using AlCl₃ (4 wt%) for Catalpa wood. Addition of DMSO with optimized electrolyte concentration improves the partition coefficient (3.3) and yield to 88.29% (5-HMF).

Efficient conversion of glucosamine to levulinic acid in a sulfamic acid-catalyzed hydrothermal reaction

Glucosamine is a monomer of chitosan, which is a biopolymer derived from the exoskeletons of crustaceans. This work investigated the conversion of glucosamine into the platform chemical levulinic acid (LA), in a sulfamic acid-catalyzed hydrothermal reaction. The optimized results of LA production showed that the conditions of 200 °C, 125 g L-1 glucosamine, 0.3 M sulfamic acid, and 15 min produced a 33.76 ± 0.19 mol% LA yield. The same conditions produced only 0.14 mol% 5-HMF yield. These results show that glucosamine is a potential bioresource to produce platform chemicals. Also, in the field of biofuels and chemical synthesis processes, the catalytic system using sulfamic acid is significant.