Damaged starch derived carbon foam-supported heteropolyacid for catalytic conversion of cellulose: Improved catalytic performance and efficient reusability

Effects of the addition of cassava starch and the size of water clusters on physicochemical and cooking properties of rice noodles

It is meaningful to explore the addition of additives and the structural characteristics of water on the quality of rice noodles. Herein, the effects of the addition of cassava starch and the size of water clusters on physicochemical and cooking properties of rice noodles were systematically studied. The addition of 25 % cassava starch effectively enhanced the swelling performance and textural properties of rice noodles. In comparison to non-activated water with large water clusters (LW), activated water with small water clusters (SW) significantly affected the interaction between water and starch molecules. Compared with LW-RN-25CS (rice noodles made with LW and 25 % cassava starch), SW-RN-25CS (rice noodles made with SW and 25 % cassava starch) presented better textural properties, including hardness, springiness, and adhesiveness. The rehydration time of SW-RN-25CS decreased from 12.31 ± 0.25 min (LW-RN-25CS) to 10.92 ± 0.46 min. This study provides reliable strategy and technology to produce high-quality rice noodles.

Recent Progress on Functionalized Nanoporous Heteropoly Acids: From Synthesis to Applications

Functionalized nanoporous heteropoly acids (HPAs) have garnered significant attention in recent years due to their enhanced surface area and porosity, as well as their potential for low-cost regeneration compared to bulk materials. This review aims to provide an overview of the recent advancements in the synthesis and applications of functionalized HPAs. We begin by introducing the fundamental properties of HPAs and their unique structure, followed by a comprehensive overview of the various approaches employed for the synthesis of functionalized HPAs, including salts, anchoring onto supports, and implementing mesoporous silica sieves. The potential applications of functionalized HPAs in various fields are also discussed, highlighting their boosted performance in a wide range of applications. Finally, we address the current challenges and present future prospects in the development of functionalized HPAs, particularly in the context of mesoporous HPAs. This review aims to provide a comprehensive summary of the recent progress in the field, highlighting the significant advancements made in the synthesis and applications of functionalized HPAs.

In Situ Self-Assembly of Nitrogen-Doped 3D Flower-like Hierarchical Porous Carbon and Its Application for Supercapacitors

The hierarchical porous carbon-based materials derived from biomass are beneficial for the enhancement of electrochemical performances in supercapacitors. Herein, we report the fabrication of nitrogen-doped 3D flower-like hierarchical porous carbon (NPC) assembled by nanosheets using a mixture of urea, ZnCl2, and starch via a low-temperature hydrothermal reaction and high-temperature carbonization process. As a consequence, the optimized mass ratio for the mixture is 2:2:2 and the temperature is 700 °C. The NPC structures are capable of electron transport and ion diffusion owing to their high specific surface area (1498.4 m2 g-1) and rich heteroatoms. Thereby, the resultant NPC electrodes display excellent capacitive performance, with a high specific capacitance of 249.7 F g-1 at 1.0 A g-1 and good cycling stability. Remarkably, this implies a superior energy density of 42.98 Wh kg-1 with a power density of 7500 W kg-1 in organic electrolyte for the symmetrical supercapacitor. This result verifies the good performance of as-synthesized carbon materials in capacitive energy storage applications, which is inseparable from the hierarchical porous features of the materials.

Insights into Preparation Methods and Functions of Carbon-Based Solid Acids

With the growing emphasis on green chemistry and the ecological environment, researchers are increasingly paying attention to greening materials through the use of carbon-based solid acids. The diverse characteristics of carbon-based solid acids can be produced through different preparation conditions and modification methods. This paper presents a comprehensive summary of the current research progress on carbon-based solid acids, encompassing common carbonization methods, such as one-step, two-step, hydrothermal, and template methods. The composition of carbon source material may be the main factor affecting its carbonization method and carbonization temperature. Additionally, acidification types including sulfonating agent, phosphoric acid, heteropoly acid, and nitric acid are explored. Furthermore, the functions of carbon-based solid acids in esterification, hydrolysis, condensation, and alkylation are thoroughly analyzed. This study concludes by addressing the existing drawbacks and outlining potential future development prospects for carbon-based solid acids in the context of their important role in sustainable chemistry and environmental preservation.

Synthesis and catalytic performance of wood cellulose nanofibers grafted with polylactic acid in rare-earth complexes based on tetrazole carboxylic acids

Stannous octanoate [Sn(Oct)2] and 4-dimethylamino pyridine (DMAP) were used to catalyze the synthesis of amphiphilic cellulose-based graft copolymers, but the acute toxicity of tin ions and DMAP prompts the need for the application of less harmful catalysts. Herein, green catalyst complexes 1-3 [M(H0.5L)2(H2O)5]·2(H2O) (M = Sm, 1; M = Nd, 2; M = Eu, 3; H2L = 4-(3-(tetrazol-5-yl)pyridin-5-yl)benzoic acid) were synthesized, and their properties were systematically investigated. Single-crystal X-ray diffraction showed that the complexes possessed a zero-dimensional structure, while the thermogravimetry and scanning electron microscopy results confirmed their stability after heating at 110 °C for 10 h. Using complexes 1-3 and DMAP as the catalysts, CNFs were grafted with l-lactide via homogeneous ring-opening polymerization to form wood cellulose nanofibers grafted with l-lactide (WGLAs), and the effects of the ratio of wood cellulose nanofibers (WCNFs) to l-lactide ([AGU]/[LA]) and catalyst dosage were studied. The polymerization followed the coordination-insertion mechanism. Under comparable reaction conditions, the grafting ratio of WGLA-1 reached 84.7 %, and the grafting ratio of complex 1 was found to be higher than those achieved using DMAP. WGLAs demonstrated good thermal stability without cytotoxicity, and the residual catalysts in the WGLAs exhibited fluorescence characteristics. Overall, amphiphilic cellulose-based materials with fluorescence emission offered a promising modification strategy to prepare high-performance polymer composites for agriculture and biomedical application.

Direct and efficient conversion of cellulose to levulinic acid catalyzed by carbon foam-supported heteropolyacid with Brønsted-Lewis dual-acidic sites

This study aimed to produce bio-based levulinic acid (LA) via direct and efficient conversion of cellulose catalyzed by a sustainable solid acid. A carbon foam (CF)-supported aluminotungstic acid (HAlW/CF) catalyst with Brønsted-Lewis dual-acidic sites was creatively engineered by a hydrothermal impregnation method. The activity of the HAlW/CF catalyst was determined via the hydrolysis and conversion of cellulose to prepare LA in aqueous system. The cooperative effect of Brønsted and Lewis acids in HAlW/CF resulted in high cellulose conversion (89.4%) and LA yield (60.9%) at 180 °C for 4 h, which were greater than the combined catalytic efficiencies of single HAlW and CF under the same conditions. The HAlW/CF catalyst in block form exhibited superior catalytic activity, facile separation from reaction system, and favorable reusability. This work offers novel perspectives for the development of recyclable dual-acidic catalysts to achieve one-pot catalytic conversion of biomass to value-added chemicals.

Porous and Stable Zn-Series Metal-Organic Frameworks as Efficient Catalysts for Grafting Wood Nanofibers with Polycaprolactone via a Copolymerization Approach

A hydrothermal method was used to synthesize two highly stable Zn(II) metal-organic frameworks (MOFs), namely, [Zn₂(L)₂(HIPA)]_n (1) and [Zn₉(L)₆(BTEC)₃(H₂O)₄·6H₂O]_n (2) (HL = 3-amino-1H-1,2,4-triazole, H₂HIPA = 5-hydroxyisophthalic acid, H₄BTEC = benzene-1,2,4,5-tetracarboxylic acid). The physicochemical properties of 1 and 2 were characterized using a range of analytical techniques. The scanning electron microscopy images confirmed the stability of the MOFs under heating at 120 °C for 12 h. Following their preparation, the two MOFs were used as catalysts in the grafting of poly(ε-caprolactone) on wood nanofibers (WNFs) by means of a homogeneous ring-opening polymerization protocol in an ionic liquid. The grafting ratio achieved using catalyst 1 was higher than that achieved for catalyst 2, wherein a maximum of 92.43% was obtained using the former. Under comparable reaction conditions, the grafting ratio of 1 was found to be significantly higher than those achieved using 4-dimethylamino pyridine, Sn(Oct)₂, and UiO-67 catalysts. In addition, fluorescence emission was detected from the residual catalysts present in the products. The calculated electrostatic potentials and average local ionization energies indicated that the grafting of ε-caprolactone on the WNFs follows a "coordination-insertion" mechanism. Overall, these two new and efficient MOF catalysts have the potential to replace highly toxic traditional catalysts in polymerization reactions. The grafted cellulose material with fluorescence emission may also be suitable for use in biomedical applications.

Highland Barley Starch: Structures, Properties, and Applications

Highland barley (HB) is a nutritious crop with excellent health benefits, and shows promise as an economically important crop with diverse applications. Starch is the main component of HB and has great application potential owing to its unique structural and functional properties. This review details the latest status of research on the isolation, chemical composition, structure, properties, and applications of highland barley starch (HBS). Suggestions regarding how to better comprehend and utilize starches are proposed. The amylopectin content of HBS ranged from 74% to 78%, and can reach 100% in some varieties. Milling and air classification of barley, followed by wet extraction, can yield high-purity HBS. The surface of HBS granules is smooth, and most are oval and disc-shaped. Normal, waxy, and high-amylose HBS have an A-type crystalline. Due to its superb freeze-thaw stability, outstanding stability, and high solubility, HBS is widely used in the food and non-food industries. The digestibility of starch in different HB whole grain products varies widely. Therefore, the suitable HB variety can be selected to achieve the desired glycemic index. Further physicochemical modifications can be applied to expand the variability in starch structures and properties. The findings provide a thorough reference for future research on the utilization of HBS.

Effects of different low temperature pretreatments on properties of corn stover biochar for precursors of sulfonated solid acid catalysts

In this study, the effects of different pretreatment methods including phosphoric acid (PA), freeze drying (FD) and phosphoric acid-freeze drying combined (PA-FD) pretreatment on corn stover characteristics and pyrolysis of corn stover samples was investigated. The results demonstrated that the physiochemical properties of biochars varied significantly. In comparison, PA pretreatment could effectively remove a large portion of inorganics and improve the fuel characteristics. PA-CSB-600 had a greater HHV, lower O/C and H/C ratios, and a lower biochar energy yield (Y_e), indicating the possibility for an attractive fuel source. PA-FD pretreatment would significantly affected cell volume and caused mechanical damage to corn stover structure. As a sulfonated solid acid catalyst precursor, the results of cellulose catalytic hydrolysis indicated that the density of -SO₃H in FD-CSA was much higher than PA-FD-CSA, but lower surface special area. Specifically, PA-FD-CSB prepared at 600 °C resulted in the maximum increase of cellulose conversion by 34.7-81.3%.

Direct conversion of cellulose to ethyl levulinate catalysed by modified fibrous mesoporous silica nanospheres in a co-solvent system

A KCC-1/Al–SO₃H catalyst with Si/Al = 5 was prepared to directly catalyse the synthesis of ethyl levulinate from cellulose in an ethanol/toluene co-solvent system. A reaction yield of 28.8 mol% was achieved after 6 h at 200 °C.

Heteropoly Acid-Based Catalysts for Hydrolytic Depolymerization of Cellulosic Biomass

Cellulose is the most abundant source of biomass, which can be converted into monosaccharide or other chemical platform molecules for the sustainable production of chemicals and fuels. Acid catalysts can promote hydrolytic degradation of cellulose into valuable platform molecules, which is of great significance in the development of chemicals and biofuels. However, there are still some shortcomings and limitations of the catalysts for the hydrolytic degradation of cellulosic biomass. Heteropoly acid (HPA), as a green catalyst, seems to be more conducive to the degradation of cellulosic biomass due to its extreme acidity. HPAs can be designed in homogeneous and heterogeneous systems. Moreover, they can be easily separated from the products in both systems by a simple extraction process. According to the unique properties of HPAs (e.g., good solubility, high thermal stability, and strong acidity), using heteropoly acid-based catalysts to depolymerize and convert cellulose into value-added chemicals and biofuels has become one of the most remarkable processes in chemistry for sustainability. In this review, the characteristics, advantages, and applications of HPAs in different categories for cellulose degradation, especially hydrolysis hydrolytic degradation, are summarized. Moreover, the mechanisms of HPAs catalysts in the effective degradation of cellulosic biomass are discussed. This review provides more avenues for the development of renewed and robust HPAs for cellulose degradation in the future.

The effect of physical morphology and the chemical state of Ru on the catalytic properties of Ru–carbon for cellulose hydrolytic hydrogenation

Ru–carbon catalysts with different physical morphologies and chemical states of Ru were prepared by different methods and used to catalyze the hydrolytic hydrogenation of cellulose at high temperatures.